Use of Bioenergy in the Baltic Sea Region

Conference Proceedings

2nd International Baltic Bioenergy Conference 02. – 04. Nov. 2006, Stralsund, Germany

Editor: Mirko Barz, Matthias Ahlhaus Fachhochschule Stralsund - University of Applied Sciences

Organizer: Fachhochschule Stralsund - University of Applied Sciences, Laboratory for Integrated Energy Systems

Patronage: Ministry of Food, Agriculture, Forestry and Fisheries – Mecklenburg Vorpommern

Sponsor: German Federal Environmental Foundation - Deutsche Bundesstiftung Umwelt DBU

The 2nd IBBC was a follow-up of the conference “Contribution of Agriculture to Energy Production“ held in Tallinn, Estonia, in 2005.

Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

The aim of the conference was to foster and to develop the know-how transfer between Baltic Sea states as well as international partners in the field of different bioenergy technologies in order to achieve a higher share of bioenergy in total energy consumption. Scientists and governmental representatives as well as biomass producers, technology producers and bioenergy consumers presented their specific expertise and demands in plenary presentations, in workshops or on posters.

The participants of the conference were invited to sign a letter of intent for closer contacts and intensive cooperation in individual projects within the framework of the Baltic BioEnergy Net (BaBEt),

Scientific Committee:

Prof. Dr. Ahlhaus, Stralsund Prof. Dr. Gerath , Wismar Prof. Dr. Gienapp, Gülzow Prof. Dr. Popp, Neubrandenburg Dr. Schlegel, Rostock, Mr. Krüger, Schwerin Dr. Halm, Schwerin

Organization Committee:

Fachhochschule Stralsund University of Applied Sciences Dr. Mirko Barz Dr. Rudi Wendorf Zur Schwedenschanze 15 D-18435 Stralsund GERMANY

Copyright © 2006 by Fachhochschule Stralsund - University of Applied Sciences

Published by Fachhochschule Stralsund - University of Applied Sciences

Printed by: Landesamt für innere Verwaltung (LAiV) Mecklenburg Vorpommern, Schwerin, 2006

All rights reserved. No part of the publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means without the prior written permission of the copyright owner.

ISBN: 3-9809953-3-X

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Contents

Preface 6 Matthias Ahlhaus

Energetic Use of Biomass: State of the Art 8 Steffen Daebeler

Enhancing the Use of Bio-energy in Estonia 16 Ruve Schank

Development of Bioenergy Utitisation, Experience of a Federal State 20 Michael Dörffel

Bioenergy in the State Mecklenburg-Vorpommern – Use and Prospects 27 Andreas Gurgel

Remote Sensing and Modeling: A tool to provide the spatial information 35 for biomass production potential Günther, K. P. *; Borg, E.; Wißkirchen, K.; Schroedter-Homscheidt, M.; Fichtelmann, B.

Prediction of Potential Productivity of Perennial C4 Grasses in Poland by 48 Means of Physiological Model (concepts and methodology) Robert Maciorowski*, Katarzyna Kołtoniak

Solid Biofuels from the Plantation on the Fallow Soil 54 Michał Jasiulewicz

Lignocellulosic energy crops – four years’ experiences from National 62 Centre for Renewable Energy in Grimstad, Norway Henrik Kofoed Nielsen*, Martin Kunze, Matthias Ahlhaus

Optimized Cropping Systems for the Agricultural Production of Energy 68 Crops in Mecklenburg-Vorpommern Jana Peters

Biomass for Energy from Rewetted Peatlands 72 Dr. Wendelin Wichtmann

Biomass Conditioning for Solid Biofuel Compositions 83 Eriks Kronbergs, Aivars Kakitis, Mareks Smits, Imants Nulle*

Monitoring of the Field-Test of Two Wood Log-Boilers/Stirling Engine 93 Combinations Ulrich Bemmann, Bodo Groß*

Investigation to the Energy Production Potential of Biomass in 99 Proportion to Energy Demand of the Administrative District of Güstrow Mathias Schlegel*, Torsten Rehl, Norbert Kanswohl

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107 Development of Unutilized Biomass Potentials in Forestry and Landscape Conservation: Logistical Challenges and Potential Uses of Innovative Telematics Technologies and Services Ina Ehrhardt *, Mike Wäsche

Potential and limiting factors of biomass energy – Estonian experience 116 of Short Rotation Forests Andres Koppel, Katrin Heinsoo*

Biomass Potential for Heating and Electricity Purposes in Pomeranian 119 Region Dariusz Mikielewicz*, Jan Wajs, Edmund Wach

Biogas to Energy – Applications, Market Development and future 129 Opportunities Frank Scholwin, Elmar Fischer*

Treatment of Digested Substrates for Nitrogen Removal and Emission 138 Decrease Ute Bauermeister*, Herbert Spindler, Anja Wild

The Potential of Production and Use of Liquid Biofuels in Latvia 148 Ruslans Smigins

Cultivation of Cereals for Starch and Bio-Ethanol Production in 156 Saxony-Anhalt Lothar Boese

Overview and Opportunities of Biodiesel Production in Kaliningrad 165 Region Aizenberg Genady, Tsipukhovskiy Andrey *

Energetic Utilization of Common Reed for Combined Heat and Power 168 Generation Mirko Barz *, Matthias Ahlhaus, Wendelin Wichtmann

Yield of Woody Biomass from Southern Norway and their Suitability for 176 Combustion and Gasification Purposes Depending on the Harvest Frequency Martin Kunze, Henrik Kofoed Nielsen*, Matthias Ahlhaus

Towards an Ecologically Sustainable Energy Production Based on 186 Forest Biomass – Forest Fertilization with Nutrient Rich Organic Waste Matter Kenneth Sahlén *, Nina Åkerback

Mixed Cropping Systems for Fermentation Gas Production on Sandy 188 Soils Matthias Dietze

Energy Maize – The Influence of Production Technique on the Yield of 190 Biomass and Biogas I. Klostermann

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State and Perspectives of Biogas Production Using Agricultural Raw 195 Materials in Mecklenburg-Vorpommern Wolfgang Schumann

The Ecological Cost of the Use of Biomass of Plants for Energy 200 Production Bohdan Deptuła

Optimisation of the fuel supply for the biomass plant Demmin 202 Simon Zielonka, Mathias Schlegel*, Norbert Kanswohl

Heat Transfer in Tube Bundles – as the Critical Link – by Taking Over 206 Energy from Biomass Furnace to Drive a Stirling Engine Tadeusz Bes

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Preface

The actual situation in our world can shortly characterized by growing population and increasing energy demand, mainly covered by fossil fuels. This results in environmental as well as climate change problems. Renewable energies offer many opportunities to overcome these problems – they can provide heat and electricity as well as automotive fuels in environmentally friendly systems and thus contribute to lower the fossil fuels dependency. Biomass as the oldest renewable energy of mankind is still playing a dominant role as an energy carrier in some African and Asian regions, where biofuels are still used in traditional ways – mainly for cooking. On the other hand biomass has a huge potential to become a more important energy resource even in industrialized countries. All over the world the opportunities of biomass are accepted and biomass has become a common term in politics resulting in new strategic analyses, political documents, legislative actions and funding programs. A lot of modern and new high-tech solutions for bioenergy systems are already developed and others are under research. Aims of the actual developments are new bioenergy systems on the basis of regional biomass potentials in rural regions. The Baltic Sea Region offers a high potential to produce biofuels for different applications to fit the growing demand of heat, electricity and fuels. In combination with its industry and engineering skills the Baltic Sea Region is predestinated as a nucleus for further development and demonstration of advanced bioenergy solutions.

In the result of the conference “Contribution of Agriculture to Energy Production“, held in Tallinn, Estonia in October 2005 representatives from policy, economy and science identified a high potential and demand for bioenergy solutions and realized the necessity of establishment of an international network (Baltic Bioenergy Net – BaBEt) for information and know-how transfer between the Baltic States to foster the energetic use of biomass. Further activities to establish a Baltic Bioenergy Net lead to this follow-up conference, renamed as 2nd International Baltic Bioenergy Conference, held in the medieval world heritage Hanseatic town Stralsund, Germany, 3 Nov. 2006. This

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2IBBC under patronage of the Minister of Food, Agriculture, Forestry and Fisheries Mecklenburg-Vorpommern is funded by Deutsche Bundesstiftung Umwelt. Aim of the conference is information and know-how transfer between Baltic Sea states as well as international partners in the field of bioenergy technologies. Plenary presentations will focus on the actual situation of bioenergy in the European Community and selected countries and areas. In three workshops the specific situation in the field of solid and liquid biofuels and biogas is presented and discussed and completed by excursions. Furthermore the representatives of all Baltic states are invited to sign a letter of intend as the next step to create the Baltic Bioenergy Net as the future basis for closer contacts and intensive cooperation in research and demonstration projects in order to achieve a higher share of bioenergy in total energy consumption. This will be our common contribution for the renewable energy future in the Baltic Sea Region.

Matthias Ahlhaus

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ENERGETIC USE OF BIOMASS IN GERMANY: STATE OF THE ART

Dr. Steffen Daebeler Fachagentur Nachwachsende Rohstoffe e.V., Germany

ABSTRACT

In 2005, 3.1 % of the primary energy demand of Germany was provided by biomass, which counted for nearly 70 % of the energy contribution of all renewable energies together. More than 90 % of “renewable” heat and 100 % of “renewable” fuels were biomass based. Biomass has a key role in reaching the ambitious climate protection and renewable energy objectives for 2005, 2010 and 2020. The paper describes past developments, the current state of the different routes for bioenergy and strategies for accelerating market penetration in the future.

Keywords: bio-energy policy, bio-energy strategy, R&D policy

1 INTRODUCTION

Germany has ambitious objectives with regard to climate protection and renewable energies, both on a national level and in line with EU and international obligations. Between 1990 and

2005, CO2 emissions have to be reduced by 25 %, a target which has not been met. The six greenhouse gases of the Kyoto protocol must be reduced by 21 % until 2008/2012, in comparison with 1990. By 2010, renewable energies shall double in relation to 2000 and contribute 12.5 % to electricity production. By 2020, 10 % of the primary energy consumption and 20 % of the electricity shall be provided by renewable energies, and the long term objective is to provide 50 % of all energies from renewable sources [1]. For transport fuels, the EU directive 2003/30/EC of 17 May 2003 stipulates a minimum share of biofuels in the market of 2 % in 2005 and 5.75 % in 2010.

In 2005, 3.1 % of the primary energy demand of Germany was provided by biomass, which counted for nearly 70 % of the energy contribution of all renewable energies together. More than 90 % of “renewable” heat and 100 % of “renewable” fuels were biomass based. 11,394 GWh electricity were produced (including 3,064 GWh from landfill gas and sewage sludge), compared with 222 GWh in 1991. Heat production amounted to 76,014 GWh, and 1.8 million tons of biodiesel, 226,000 tons of bioethanol and 196,000 tons of vegetable oils, equivalent

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to 22,330 GWh, were consumed compared with 2 GWh in 1991 (1). The annual turnover in 2005 of biomass related industries was 3.4 billion €, and more than 60,000 persons were, directly or indirectly, employed in this sector. The bioenergy share is still low in comparison to some other EU countries, but a significant increase in comparison with the situation some decades ago.

2 DEVELOPMENTS UNTIL 2006

2.1 The role of bioenergy in the German energy system

- For decades, bioenergy played only a minor role in the German energy system. Its use was limited to traditional applications. - In the mid seventies of the last century, three events changed the attitude towards renewable energies in general and specifically towards biomass: - in 1972, the Club of Rome report “Beyond the limits” of a team around Dennis Meadows highlighted the risks of economic growth, - the oil shock in 1973 demonstrated the vulnerability of energy supply, - increasing agricultural surpluses caused considerations of alternatives.

Considering later criticism, it is rather surprising that bioenergy activities in the late 70s started with liquid biofuels. For heat and electricity, studies in the 80s concluded that the potential contribution of biomass was too small to be economically interesting [5].

2.2 Obstacles for bioenergy deployment

- Despite considerable efforts to increase the contribution of biomass to energy provision, several difficulties had to be faced: - Market prices for fossil resources did not develop as predicted, making it difficult for biomass to compete without additional support. - The responsibility for the political framework and R&D funding was with different ministries; the integration of activities turned out to be difficult. - Due to the federal structure of Germany, even R&D funding was allocated to different ministries and programmes. Only in 1992, federal R&D was put under the responsibility of one ministry and one agency. Funding was and is also provided by the German Laender and other bodies, and continuous efforts are required to co- ordinate research activities. - R&D priorities and budgets fluctuated heavily. Although the federal ministry of research spent more than 1.5 billion € for research on renewable energy sources (RES) and rational use of energy between 1974 and 1992, only 2 % or 33 million €

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were devoted to biomass, and this only from 1989 to 1992 (2). Since 1993, federal R&D bioenergy support varied between 1 and 7.5 million € per year. This made it difficult to finance huge research programmes; for research groups it is not without risk to focus exclusively on bioenergy. - For decades, agriculture was the main political promoter of renewable biological resources and bioenergy. Environmental policy discovered the potential of bioenergy rather late. - A market which relies heavily on the political frame conditions is not too attractive for industry. Big energy companies tend to focus on their classical business; smaller ones sometimes do not survive the ups and downs of political support. Industrial interest was limited and so was the market uptake of R&D results.

Besides these similarities, also differences can be highlighted for the different energy applications.

2.3 Liquid biofuels

For liquid biofuels, until 1990 huge efforts were made to develop bioethanol as a fuel. However, the conclusion in the late 80s was that it was not possible to install an economically viable ethanol production in Germany. This statement given, also political efforts to promote biofuels were limited. Until 2003 only pure, unblended biofuels were exempted from the mineral oil excise duty. So in practice the only biofuel coming on the market was biodiesel, increasing its market share to 2 % of the diesel market, or 650,000 tons, in 2003. Since 2004, also blended biofuels were exempted from the mineral oil tax, opening the market for bioethanol and pure vegetable oils and leading to a consumption of more than 2,2 million tons in 2005. However, biodiesel still is the major driver.

2.4 Electricity from biomass

For electricity from biomass, already the electricity feed-in act of 1991 (Stromeinspeisungsgesetz) set minimum prices for electricity from renewable feedstocks. But a first boom was only caused by the renewable energy act (EEG) and the related biomass ordinance issued in 2001. A major revision became effective in August 2004. Electricity from biomass is eligible for minimum purchase prices of up to 21.9 ct/kWh. Guaranteed electricity prices depend on the capacity of the plant, biomass quality, technologies applied and whether also the heat is used. If dedicated energy crops or manure are used as feedstock, a premium of up to 6 ct/kWh is applied. Prices are going to be guaranteed for 20 years, with an annual price decrease for new installations of 1.5 %

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starting 1 Jan 2005. From a government point of view, the EEG has the additional appeal that it is budget neutral, i.e. the costs are paid by the electricity consumer. By the end of 2005, 130 solid biomass fed plants with an installed electrical capacity of 790 MW were in operation [4]. Most plants have between 10 and 20 MW electrical capacity, as 20 MW is the maximum eligible capacity for the guaranteed price. In 2003, around 3.5 million tons of waste wood and only very limited amounts of “virgin” biomass were used, as waste wood is cheaper and feedstock logistics are easier. According to estimates, 50 % of the waste wood potential, but only 8 % of the total biomass potential are being used so far [5]. Heat is only used to a limited extent, and the conversion technologies for electricity from biomass implemented in the market are well established. The 2,700 biogas plants operational by the end of 2005 in Germany have an electrical capacity of 665 MW [4] and produced, according to the Working Group on Renewable Energies/Statistics (AGEE-Stat), 2,500 GWh electricity [1]. More electricity from biomass in a broader sense is produced from landfill and sewage gas, as well as the biodegradable part of municipal solid waste (MSW). In 2005, this amounted to 5,114 GWh [1]. Both for solid and gaseous biomass, the waste streams are already well exploited. Therefore a mobilisation of new potentials is needed to increase the electricity production further.

2.5 Heat from biomass

For heat from biomass, the statistical assessment is difficult. For 2005 the final energy use is estimated to be around 76,014 GWh [6]. More than 90 % are wood based. The main use takes place in boilers between 15 and 1000 kW capacity [7]. A rather new development are pellet boilers with 44,000 installations by the end of 2005; pellet boiler manufacturers forecast 26,000 new installations for 2006 alone [10]. Investment aids on the federal and Laender level have given some impetus. However, the use of biomass is still mainly focused on southern Germany and users with a direct link to forestry, and despite a huge potential, market growth has been slower than for electricity and transport fuels.

3 IMPROVED FRAMEWORK FOR BIOMASS IN 2006

3.1 Objectives and current status

By 2004, CO2-emissions had fallen by 16 % in relation to 1990. In 2005, 4.6 % of the primary energy consumption, 10.2 % of the electricity and 3.6 % of the fuel consumption were “renewable” [6]. The comparison between the actual results and the political targets for 2010 – 4.2 % of primary energy consumption and 12.5 % of electricity provided by renewables; 5.75 % of the fuel consumption by biofuels - shows where political efforts and R&D

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measures are most needed.

Transport is the only economic sector in Germany with increasing CO2-emissions. Besides more energy efficient transport, biofuels are the only option to reduce these emissions. For liquid biofuels, the German 3.6 % biofuels in 2005 were more than the EU target of 2 %. The Biodiesel capacity will be close to 3.6 million tons per year by the end of 2007, if current plans materialize; ETBE is already being produced and blended in Germany. Three dedicated bioethanol plants with a capacity of 500.000 tons are operational and further ethanol plants are under construction. For electricity, there is still some way to go until the 2010 target of 12.5 % will be reached. Besides wind energy, where increases are mainly expected by the repowering of existing wind mills and new off shore wind mills, biomass will have to play a key role. And from an environmental point of view, it is important to use both heat and electricity. Energy crops are already a major feedstock for biogas plants, and the ffed- in of biogas into the natural gas grid is investigated and already implemented in pilot projects, thus converting biogas into electricity and heat in places where demand for both forms of energy exists. As heat provision counts for 50 % of the total contribution of RES and biomass is the main energy source here, it is crucial to intensify the efforts also in this area. The Federal Ministry of Agriculture considers it feasible to double the contribution of biomass to primary energy supply from 1.6 % in 2002 to 3.2 % in 2010. The technical potential of biomass is estimated at 1,230 PJ or 8.5 % of the primary energy consumption [8]. This is based on the assumption of 2 million hectares of energy crops. Recent studies on behalf of the Ministry of Environment forecast a long term potential of 4.5 million hectares of energy crops for Germany [9]. This would increase the potential contribution of biomass significantly.

3.2 Improvement of political framework

To promote renewable energy sources and to increase the use of biomass, several improvements of the political framework have been made recently or are in the final step of approval: - To reach the 2010 biofuel target of 5.75 % of the transport fuel consumption, equivalent to 3.6 million tons of fossil fuels, the government is about to introduce new legislation, which changes the political framework quite drastically again. The the energy taxation act is already amended and a new biofuels quota act will be introduced shortly. Since 1 August 2006, pure and blended biodiesel is taxed with 9 or 15 ct/litre. For pure biodiesel, mineral oil tax will gradually increase to the full diesel rate of 47 ct until 2012. For pure vegetable oils the same changes apply, but start one

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year later. As of 1 January 2007, a mandatory biofuel quota for all taxable transport fuels will be introduced. This starts with 4,4 % for diesel and 2 % for gasoline. By 2010, the overall biofuel quota will be 6 % (measured as energy content), so slightly more than the EU target. Biofuels under the quota act will no longer be exempted from the mineral oil tax. However, special provisions for “2nd generation biofuels”, such as biomass to liquid (BtL), ethanol from lignocellulosics, E85 and biogas will facilitate their market introduction. - For electricity and heat, amendments to the current legislation are under discussion.- In addition to the existing investment aids for biomass boilers, a “renewable heat act” is under consideration and has already been discussed intensely. But as there is no common “bottleneck” in the heat market as for electricity, the practical implementation is complex.

4 SHORT AND MEDIUM TERM RESEARCH TARGETS

4.1 General targets

In general, R&D is needed to unlock so far unexploited biomass potentials, and to develop efficient, ecologically and economically sound and decentral processes for the provision and utilisation of bioenergy carriers. Examples are: - the gasification of biomass,

- decentral CHP based on biomass,

- application of modern energy technologies (fuel cell, micro turbine, gasification),

- the production of synthetic biomass to liquid “BtL” fuels.

Thermochemical gasification is a key technology for bioenergy, both for the provision of combustion gases for gas and steam turbines and fuel cells, and for the provision of synthesis gas for liquid biofuels, methanol for fuel cells and, in the long term, hydrogen. R&D efforts have led to several gasification technologies, but a market breakthrough is still missing. Also, activities have so far mainly been focused on the electricity production. The most promising new biofuel is BtL. BtL can be produced from any kind of biomass in a two step process of first gasification and then either Fischer-Tropsch or methanol synthesis. In comparison to biodiesel and bioethanol, it has several advantages. BtL is not limited to one or two crop species as raw material, thus opening a huge potential biomass production areas with high energy yields per hectare. It is the first really market driven biofuel with strong involvement of the car manufacturers. BtL is compatible with existing diesel or gasoline, and helps to fulfil stricter emission limits even with engines already on the market. However, the technology still needs considerable development and the economic and

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environmental balance needs to be investigated and optimized. For heat and electricity, a key issue is the support of new anaerobic digestion technologies, such as solid state fermentation, and the application of the fuel cell technology. A main focus also lies also on improving technologies and reducing emissions for the utilisation of annual biomass, such as straw, whole crop cereals, and wood. Finally, integrated concepts, e.g. for electricity production and heat utilisation, will be supported. Developments in the areas of BtL and anaerobic digestion call also for R&D on energy crop breeding and cultivation, as well as biomass logistics.

On the federal level in Germany, the Ministry of Food, Agriculture and Consumer Protection is the main promotor of biomass and bioenergy research with an annual budget of more than 50 million €. The Fachagentur Nachwachsende Rohstoffe serves as a focal point for these activities and is in charge of administering and implementing the R&D budget.

5 CONCLUSION

In comparison to the previous decades, the political and economic frame for bioenergy is favourable: - Limited availability, environmental problems and costs of fossil fuels have been widely recognized. - The political conditions for electricity, heat and transport fuels from biomass are positive and reliable. - International co-operation is increasing.

So it is expected that the years to come will see a huge expansion of bioenergy in Germany.

6 LITERATURE

[1] Federal Ministry of Environment (BMU): Renewable Energy Sources in figures, Issue May 2006.

[2] Bundesministerium für Forschung und Technologie: Erneuerbare Energien. 1992.

[3] Institut für Energetik und Umwelt: Fortschreibung der Daten zur Stromerzeugung aus Biomasse. On behalf of AGEE-Stat 2004.

[4] Institut für Energetik und Umwelt: Monitoring zur Wirkung des novellierten Erneuerbare- Energien-Gesetzes (EEG) auf die Entwicklung der Stromerzeugung aus Biomasse. 2. Zwischenbericht, Februar 2006.

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[5] Bundesministerium für Forschung und Technologie: Nachwachsende Rohstoffe. 1986.

[6] Arbeitsgruppe Erneuerbare Energien-Statistik (AGEE-Stat), February 2004.

[7] S. Schneider, D. Falkenberg, M. Kaltschmitt: Erneuerbare Energien in Deutschland – Stand 2003-. BWK 4/2004.

[8] Bundesministerium für Verbraucherschutz, Ernährung und Landwirtschaft. Konzept zur energetischen Nutzung von Biomasse. March 2004.

[9] Oeko-Institut et. al. : Stoffstromanalyse zur nachhaltigen energetischen Nutzung von Biomasse. Study on behalf of the Federal Ministry of Environment, 2004

[10] Press release exhibition/conference „Pellets 2006“, from 24 July 2006

Author Information Dr. Steffen Daebeler Fachagentur Nachwachsende Rohstoffe e.V. Hofplatz 1 18276 Guelzow, Germany Tel. +49-3843-69300 Fax. +49-3843-6930102

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Enhancing the Use of Bio-energy in Estonia

Ruve Schank Ministry of Agriculture of Estonia

Status in Estonia – shares and areas

In 2005 the renewable energy sources made out about 12% of the primary energy supply. This is largely due to the contribution of wood fuel.

Electricity in Estonia is mainly produced from oil shale (95%). However the utilization of renewable energy sources grew intensely during 2005 for electricity production. Totally 22 hydro and 7 wind power plants contributed to the electricity production. In total the electricity production from renewables made out 0,7%. Compared to 2004 the amount of electricity produced from wind power was 7 times larger. At the end of the year the total installed capacity of wind power reached 36,8 MW, and forecasts for 2006 shows potential to reach 60 MW or more.

The largest use of biomass in Estonia has traditionally been for heat purposes. Most of the firewood is consumed in households, while wood waste and wood chips are used for the production of heat on a larger scale. Currently there are 752 heat plants that use wood fuel as their primary supply. The joint production reaches 836 MW, which shows a clear indication of growth compared to the year 2004. Combined heat and power is also being utilized in varying degrees in a number of Estonian towns with a total of16 functioning heat and power plants. However it can be mentioned that the total capacity for combined heat and power in Estonia as well as preferred technology is still a question for debate.

Wood waste from wood processing processes in industry is currently being utilized and pellets and briquettes are being produced in large quantities. The production of pellets and briquettes was 237 000 tons in 2005. Currently however the majority of the domestic production is still being exported to other states (in 2005 230 000 tons or 97 % were exported).

On the basis of the Directive 2003/30/EC Estonia’s objective is to achieve an indicative proportion of biofuels and other renewable fuels for transport purposes of 2% in 2006 and 5,75% in 2011. For transport purposes practically all fuel is still being imported at this time. However, four licenses for biofuel production have currently been issued (three licenses for liquid biofuels and one for solid biofuels) in Estonia. Under the Alcohol, Tobacco and Fuel

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Excise duty Act biofuels are also now exempt from excise duty. Permission to exempt several biofuels from excise duty was granted from the European Commission in a letter dated 27 July 2005. Although it could be assumed that this would have a positive effect on Estonian biofuels production and consumption, it is still to soon to give any specific indication of to what extent this has actually occurred. During 2005 the biofuel produced and released for consumption was still being exported to other member states.

Today energy crops (mainly Rapeseed) are grown within an area that does not exceed 50 thousand hectares. The harvest is about 70 – 80 thousand tonnes, which is not sufficient to produce biodiesel. Cereal production (approximately 600-760 thousand tonnes) does not currently cover domestic demand for fodder, foodstuff, seed and industrial needs. Therefore additional cereal is being imported to cover demand. The acreage covered by fodder crops and permanent pasture is fully utilized for animal feed. There is however a large amount of currently unused agricultural land (approximately 400 thousand hectares) that could be cultivated for energy crop production, but it should be kept in mind that this land is of varying quality and it is unclear how much of it can actually be used for successful crop production.

Biomass potential in Estonia

Estonia holds relatively large natural wood assets, which have developed over the last 80 years when former agricultural land has been abandoned. In total Estonia has an estimated forest area of 2, 27 million hectares. According to the Estonian Forestry Development Plan, which defines the strategies that are essential for Estonian forestry and activities for their implementation, the forestry sector will produce 2 million m3 per year during the next years of low-quality wood that has yet not found a consumer. Also the more effective collection and use of forest residues holds potential.

Though peat is not considered a renewable resource within the European Union, it can be mentioned that the Estonian peat reserve was 1073 million tons in 2004, including the consummation reserve of 301 million tons and extra reserve of 771 million tons. Peat production and consumption faces problems of how to solve and agree on sustainability issues.

Much of the future potential for energy crops depends on how well land resources are utilized and moreover how much of the estimated 400 000 hectares of abandoned arable land can be effectively taken into use. As mentioned earlier mostly oilseed crops currently cover the area used for energy crop production. It has been estimated that the total potential

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area for oilseed in Estonia at this time would be around 50 thousand hectares, which more or less corresponds to the current area actually covered by oilseed crops. However further potential for other crops that could be used for energy production in Estonian conditions (for example sugar beet etc. for bioethanol) are still unclear but are likely to hold greater promise for the future.

Problems defined and corresponding goals to be defined

There has been high hope for bioenergy and its possibilities corresponding to many different problems facing society. Energy dependence has been one central problem receiving a lot of attention lately. The Estonian reserve of oil shale has guaranteed certain independence. However the production of oil shale has historically been quite inefficient and harmful to the environment. More attention is now being turned to renewables and their potential to produce energy.

Bioenergy may also present solutions for rural society as it has often been assumed that bioenergy will generate or preserve employment. Of course this will depend on the kind of biomass or bioenergy being produced and specific technology being used. Similarly the use of the abandoned arable land resources has the potential to create more diversified sources of income for farmers and a more productive and efficient agricultural sector.

The public awareness of bioenergy today is quite low and may present problems for the actual consumption of bioenergy. For this purpose more action is needed to promote the public awareness of bioenergy and to guarantee that necessary information is made available for those interested. This is also connected to a need to generate better statistics on bioenergy and to promote a more coordinated research on bioenergy.

Measures planned

Currently measures are being planned within the framework of the development plan for the use and promotion of biomass and bioenergy for the years 2007-2013. This development plan is currently under preparation and will be completed by the end of the year 2006.

One measure being planned aims at promoting and coordinating research and development. A very important task is to analyze what kind of biomass and bioenergy is the most effective and optimal in the Estonian case. Also the existing scientific competence within the bioenergy sector needs to be identified and analyzed in order to achieve an interdisciplinary

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science as well as a research and teaching standard corresponding to international standards.

Another important measure will aim at analysing the need for different kinds of information on the one hand and gathering, analysing and distributing the information found necessary on the other hand.

Other measures will be targeted towards furthering public awareness, international cooperation and generating necessary standards. Also central to the development plan is developing favourable tax policies, support systems and public procurement rules as well as placing possible obligations on producers or consumers in regard to bioenergy.

International background

In an international context information exchange is of great importance. For such efforts network building is necessary on different levels in order to promote bioenergy production and utilization. Current efforts involve developing a communication network on bioenergy in the Baltic Sea region. Within this framework common research issues and projects may be realized. Also possibilities presented for joint pilot projects and innovation transfer may be realized within international cooperation.

Economic impact

The different support systems used in different countries to promote bioenergy may create situations where production of biomass and bioenergy on the one hand and consumption of it on the other is effected. The need to create a more unified market for energy is clearly an important issue. Questions like waste management may also introduce extra costs or unequal treatment.

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Development of Bioenergy Utitisation, Experience of a Federal State

Michael Dörffel (Head of Department) Ministry for Agriculture and Environment of the Federal State of Saxony-Anhalt, Germany

Importance of renewable energy to Saxony-Anhalt

The Federal State of Saxony-Anhalt considers the expansion of the renewable energy sector to be one of the great options in an attempt to counter both climate change and the growing consumption of limited resources of fossil fuels as well as increasing dependence on their imports. According to EUROSTAT, the Statistical Office of the European Communities, the energy import dependency rate in the European Union reached a percentage of 44% in 2005. In 1995 this rate amounted to only 44%. The objective set out in the 1997 Climate Protection Programme of Saxony-Anhalt of freezing greenhouse gas emissions at the 1994 level has been accomplished. Carbon dioxide savings of 34 million tonnes in Saxony-Anhalt since 1990 amount to 21.8% of the established all-German CO2 reductions, and are an important step towards the fulfilment of Germany's obligations under the Kyoto Protocol.

Hence, there is general consensus in Saxony-Anhalt that the share of renewable energy in the current and heat sectors should be increased. However, renewable energy sources can only be successful in the market if their efficiency is improved such that they can compete with conventional energy sources. Apart from intensified, application-oriented research and development efforts, this requires, in particular, special promotion instruments adapted and designed such that they compel reductions of cost. Otherwise, permanent subsidies exerting a contra-productive effect will be created, which hinder the necessary technical and technological development rather than promoting it.

Legal outline conditions for the renewable energy sector

By adopting the Act on Granting Priority to Renewable Energy Resources in the Electricity Sector (Renewable Energy Sources Act) Germany has set out provisions for efficient incentives for investments in renewable energy installations. They are based on the obligation to purchase electricity from renewable energy sources and against fixed, but graduated prices.

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Incentives for heat generation from renewable energy sources, for feeding biogas, if not intended for power generation, into existing natural gas grids, for treating biogas to use it as fuel or whole crop gassing purposes and subsequent processing of the synthetic gas in biorefineries to produce synthetic fuels or basic chemical substances have not yet reached the stage of those in the electricity sector.

Graduated prices for feeding electricity as set out in the amendment to the Renewable Energy Sources Act of 2004 contribute to the intensified utilisation of biomass potentials. The Renewable Energy Sources Act provides for additional incentives for co-generation as well as innovative technologies. In particular, those installations which exclusively use renewable raw materials get better remuneration. First of all, they include installations processing untreated plants or parts of plants and liquid manure within the meaning of the Regulation (EC) No. 1774/2002. In particular, this has improved the conditions for agricultural biogas installations.

Achievements made in the field of renewable energy resources in Saxony- Anhalt

Still in the mid-nineties renewable energy sources played a rather subordinated role in Saxony-Anhalt. However, their share rapidly increased to enormous 18.4 percent by the end of 2004 and, amounting to about 2.87 thousand million kWh of the overall power production, is higher today compared with the other German federal states, being double as high as the federal German average. The largest portion is wind energy with 87%, followed by biomass with 8.8% and hydropower with about 1.6%.

The wind energy sector in Saxony-Anhalt is further enhanced on a high level even if the zenith was exceeded in 2002 due to lacking areas suitable for wind energy use. By the end of 2005 Saxony-Anhalt had a total of 1,652 wind energy installations with an overall installed capacity of 2,201 MW. Thus, the installed wind capacity is even greater than the capacity of conventional electricity production in Saxony-Anhalt.

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Electricity from renewable energy sources

3,500,000

3,000,000

2,500,000

RE total 2,000,000 Water M Wind W Photovoltaics h Landfill gas/gas from ,.500,000 Biomasspurification plants Others

1,000,000

500,000

0 1996 1997 1998 1999 2000 2001 2002 2003 2004

Over the past years a number of manufacturers of plants for the production of renewable energy have settled in Saxony-Anhalt. Typically, several thousand jobs were created in the wind energy sector. On the other hand, the intensified use of wind energy has led to a situation whereby public grids, in particular in the medium-voltage range, are often overloaded.

This situation is due to the high concentration of wind power installations in wind parks, the highly unsteady power generation by these installations and high supply into the grids at times of low network loading. Since the early nineties Saxony-Anhalt's population has been declining, whereas its economy has been continuously restructured. This also has impacted the supply structures in the energy sector.

Network expansion and upgrade could not cope with the rapid development in the wind energy sector. As a result of problems in securing supplies grid access has become more difficult, in particular for installations of energetic biomass use. As this is an obstacle to the further intensification of the use of bioenergy, the State Government have intervened to help solve this problem, although the Renewable Energy Sources Act does not provide for law enforcement by federal states. The dialogue initiated in 2005 by the State Government with grid operators, investors and associations is aimed at:

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• identifying solutions for all current investment projects affected so as to connect to the grid as soon as possible, • finding an understanding about a preventive strategy of how to avoid problems in future, and • reaching an understanding what the State Government can do to give the concerns and interests of the parties involved more attention in future amendments to existing acts, e.g. to the Renewable Energy Sources Act.

To this end, the Otto-von-Guericke-University of Magdeburg developed a Forecast for Employing Grid Management Measures in Saxony-Anhalt. This study yielded important results for grid management. Moreover, this study, which had been ordered by the two biggest grid operators of Saxony-Anhalt, is an important basis for planning the further extension of the renewable energy sector in Saxony-Anhalt within the meaning of the Coalition Agreement of the State Government. However, this does not mean that all questions and problems have been solved to date.

The dialogue will be continued and additional discussions will be held to identify further solutions to the question how to successfully integrate renewable energy sources in power grids. Saxony-Anhalt would be glad to make its experience available to all interested parties.

For several years the State Government have focussed their efforts on the expansion of the renewable energy sector by including biomass use, the exploration of geothermal energy sources and the use of solar heat.

Biomass use in Saxony-Anhalt

Saxony-Anhalt has most fertile soils and most favourable conditions for crop growing. For several years Saxony-Anhalt has been ranking among the leading federal states in terms of the overall production of renewable raw materials. In 2006 the overall area for the production of renewable raw materials was about 90,400 ha under energy crop and set-aside area allowances. This means that renewable raw materials are produced on about 7.7% of the agricultural area of Saxony-Anhalt.

Another characteristic of Saxony-Anhalt's position is the high level of biomass use. The following figures are proof of that.

• About 50% of the all-German production capacity of bioethanol is presently situated in

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Saxony-Anhalt. Two large companies have a capacity of 265,000 MT/a. Two other installations are at the planning stage and are contemplated to increase the capacity to about 467,000 MT/a.

• About 17% of the all-German production capacity of biodiesel (330,000 MT/a) is produced by six companies in Saxony-Anhalt. Seven other installations have reached the seeking planning permission or approval, increasing the biodiesel production capacity to more than 1 million MT/a.

• The forestry and wood sectors have been strongly expanded for physical and energetic biomass use. Their structures are mainly determined by paper and pulp as well as wood processing companies. Investments of more than 1.5 thousand million euros have been made over the past eight years.

• Currently, about 70 biogas installations are in operation or under construction and another 74 have been approved or are awaiting approval. It is assumed that there are more than 400 cost-effective locations for biogas installations in Saxony-Anhalt.

The increasing number of agricultural biogas installations erected over the past two years decisively contributes to the reduction of ammonia and methane emissions in the agricultural sector by making energetic use of liquid manure.

Under the European National Emission Ceilings Directive (2001/81/EC - also called the NEC Directive) Germany has undertaken not to exceed specified limit values of pollutants. This seems to be rather problematic, in particular under the given emissions in the agricultural sector. Also in the field of methane, where the climate impact is 22 times as high as that of carbon dioxide, much needs to be done. Again, biogas installations utilising liquid manure can make a major contribution.

The agricultural structures in the animal breeding sector of Saxony-Anhalt, which are typical of the east of Germany, facilitate emission-reducing measures at clearly lower cost than structures with small and smallest enterprises. Costly measures for protecting the environment are only reasonable in economic terms if enterprises have a reasonable size. With more than 300 large animal breeding farms Saxony-Anhalt's conditions are especially favourable in this respect.

Exemplary activities in the field of biomass use in Saxony-Anhalt

To support the expansion of biomass use the State Government developed a Biomass Catalogue in 2002 to reveal biomass potentials of the state, identify existing obstacles in

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using such potentials, and inform about the state of technology and requirements for development. The aim of this catalogue is to support potential investors in preparing their investments and reduce investments risks. (also refer to: http://www.sachsen-anhalt.de/LPSA/index.php?id=fldkm0btqqygt)

In 2003 the state established a Coordination Office for Renewable Raw Materials (KoNaRo). This coordination office is a place where all players in the field of renewable raw materials in Saxony-Anhalt can meet and be contacted. It coordinates and bundles projects, organises the exchange of information between the agricultural, industrial, research and administrative sectors and stands for active public relations. (also refer to: http://lsa-st23.sachsen-anhalt.de/llg/konaro/main34_1.htm).

Despite all these favourable conditions, there are still obstacles to overcome in the future. Although a lot of expertise, sophisticated installations and funding models have been developed and know-how in operating them has been made, many investors are still lacking expertise and experience. Therefore, the Ministry for Agriculture and Environment organises specialist events at regular intervals, such as about biogas with a special focus on funding and contracting.

In 2005 Saxony-Anhalt established a biomass information platform named Biomass Guide of Saxony-Anhalt. This guide offers information in the field of energetic and physical biomass use. Moreover, this guide serves to contribute to the networking of various players like manufacturers of installations, planners, research and training institutions, financial institutions, associations, authorities, etc. (Also refer to: http://www.sachsen-anhalt.de/LPSA/index.php?id=13652).

Moreover, the state supports specific projects, such as the project named Energetic Use of Cereals. For the duration of the project, i.e. two years, the state administration will operate a small furnace of a special design for the thermal use of cereals to study the operating and emissions behaviour of the biomass boiler when operated with cereals over two heating seasons and establish whether such installations are eligible for approval.

In the field of bioenergy there is a close cooperation between the state institutions of Saxony-Anhalt, Saxony, and Thuringia. This is reflected, for instance, by

• the annual Mitteldeutscher Bioenergietag and

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• a joint education offer of the three state institutions within the framework of a modular bioenergy education initiative. This education offer with its modular structure starts with the biogas module.

The future-oriented development of using biofuels is enhanced by the state of Saxony- Anhalt providing coordination and promotion, by employing all opportunities and capacities of the industry, training and research institutions, agriculture and forestry.

The first steps in implementing a strategy aimed at providing overall support for biofuels in view of the very favourable prospects of biomass use in the federal state, were the establishment of a Biomass to Liquid Forum (BtL Forum) by the Ministry for Agriculture and Environment of the Federal State of Saxony Anhalt in December 2005 and the performance of the 2006 Biofuel Study. (Also refer to: http://www.sachsen-anhalt.de/LPSA/fileadmin/Elementbibliothek/Master- Bibliothek/Landwirtschaft_und_Umwelt/B/Biomasse/Biokraftstoffstudie_ST.pdf).

The fields of renewable energy with special focus on biomass use and geothermy have been anchored in the programming of the new 2007-2013 EU Structural Funds period.

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Bioenergy in the State Mecklenburg-Vorpommern – Use and Prospects

Dr. Andreas Gurgel State Research Center of Agriculture and Fishery Mecklenburg-Vorpommern, Gülzow, Germany

Summary Fossile energy sources are limited. Furthermore the use of fossile energy damages our environment. That´s why we are looking for alternatives. One of them is bioenergy. It is reneweable and does´nt intensify the green house effect. All nations of Europe try to increase the utilization of bioenergy now, and so does Mecklenburg-Vorpommern. In a study we tried to estimate which part of primary energy consumption we are able to replace by bioenergy. The result is, that it would be possible to reach nearly one quarter in Mecklenburg-Vorpommern. In addition we also will export a respectable amount of bioenergy.

Prevailing Circumstances A lot of effort is made in the state Mecklenburg-Vorpommern as well as in Germany and in the European Community to increase the portion of bioenergy. Why do we do so? We all know that the amounts of petroleum, natural gas and coal are limited. So we have to look for alternatives for energy supply. During the last few years, fossile energy becomes more and more expensive. But the demand on energy is rising constantly. Now it´s the turn of bioenergy to save energy supply for the future. Bioenergy takes an important contribution to reduce the greenhouse effect. Since 2004 the circumstances of bioenergy have crucially improved. In this year started the “Law of reneweable Energies” in Germany. There was determined a defined payment for electric current. This system of guaranteed prices was an important step to get profit by producing bioenergy (Table 2).

The European Community has posed several targets of use of Bioenergy. This targets are specified by each member nation. In Germany a portion of 12.5 % of electricity use is aspirated to be produced by reneweable energy sources in the year 2010. At the field of Biofuels the target is to replace 5.75 % of the fuel consumption by biofuels till 2010. These targets get their realizing step by step. The member states are committed to report about it. For the succeding future there is planned much more, for instance to increase the portion of biofuels up to 8 % in the year 2015.

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The german government pursues several targets by supporting bioenergy production and consumption: • long-term development of energy supply and protection of climate, nature and environment • a portion of reneweable energies on current consumption of 12.5 % • decreasing external costs of energy • declining dependence on fossile resources • development of techniques at the field of reneweable resources.

Nearly for one year there are conflicts between the new government and the branche of biofuels due to the new contract provisions on mineral oil tax. The problems are solved not yet.

The state Mecklenburg-Vorpommern has a conception to support bioenergy. Several projects can be promoted by supporting programmes.

Potentials of bioenergy in the State Mecklenburg-Vorpommern In the ferderal state Mecklenburg-Vorpommern there are about 1.074 Mio hectares of arable Land. It never would be possible to grow only energy crops on all this arable Land. First of all it´s necessary to save the food and feed production. It is estimated that about one third of arable land in Mecklenburg-Vorpommern can be used for growing bioenergy crops. Several crops are useful as bioenergy crops. Choosing the right crops is dependent on the way of conversion and also on the yields under conditions of Mecklenburg-Vorpommern. Our state is a Rape-seed-state number 1 all over Germany. About 230,000 hectares of rape seed are growed every year. 140,000 of them are used to produce biofuels. Since the commencement of the German Reneweable Energies Law the role of maize has increased because maize is the main raw material as a co-substrate in biogas plants. So the area of maize has developed up to 10,000 hectares in the year 2005 in Mecklenburg-Vorpommern. Cereals have developed to an important raw material. Cereals can be used to produce biofuels or as a solid fuel. The straw of cereals also can be used for bioenergy production as well. It is estimated that about 60 % of the straw of cereals can be removed from the arable land for energy production. But bioenergy material is not growed only on arable land. There are also facilities to use greenland grasses, wood and organic wastes to produce bioenergy (table 1).

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Table 1: utilization of energy biomass in 2005 and estimated technical potentials for the year 2020 Utilization in the Estimated Potential Year 2005 for the year 2020 1 agricultural biomass area area hectares hectares crops on arable land co-substrates for biogas plants (maize, cereals, 9,500 60,000 catch crops) Biofuels (rape seed, cereals, sugar beet) 165,000 200,000 solid fuels (wood, cereals, energy grasses) 0 102,000 sum hectares 174,500 362,000

Energy content Energy content Petajoule Petajoule by-products (straw) 0 19.3 wastes (liquid manure, excrements)… 0.6 4.7

2 forestry Biomass quantity quantity tons tons waste wood from forestry and landscape 116,000 166,000 conservation by-products from sawmilling, timber from pulling 530,000 430,000 down sum t 646,000 596,000

3 Sum PJ total 20.2 69.1

The table 1 shows that the federal state Mecklenburg-Vorpommern has a potential to triple bioenergy production, regarding the danger of removing all biomass from the field. The reproduction of organic matter is important for the fertility of the soils. By producing bioenergy crops we want to get high yields from the whole plants. Regarding to reproduction of humus and soil fertility a certain percentage of harvest arrears from the biomass must stay on the field. That´s why only 60 % of the straw can be removed from the field. Together with the straw of rape seed the organic matter is enough to save the content of carbon in our soils.

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Biogas in the state Mecklenburg-Vorpommern The basis for the very fast rising number of biogas plants in Mecklenburg-Vorpommern as well as in Germany is the payment for the electric current which is regulated in the Reneweable Energy Law since 2004. This Payment is guaranteed for a period of 20 years (table 2).

Table 2: Payment for electric current from biogas plants payment category payment in Cent / kWh dependent on the electrical power

up to150 up to 500 up to 5 from 5 MWel. kWel. kWel. MWel. basis payment 11,5 9,9 8,9 8,4 add-on payments Bonus for biomass + 6 + 4 - Bonus for cogeneration of heat and + 2 electricity Bonus for innovative techniques + 2 - duration of guaranteed payment 20 years annual degression decreasing payment by 1.5 % compared with the (from 2005) previous year

There are several models of operating biogas plants. Either the farmer can found a new enterprise or he can sell co-substrates and liquid manure to biogas plants. There are also different models between this two extremes. A very important fact in the biogas production is a bold change in the crop rotations on the field. The percentage of co-substrates especially maize has risen considerably. This diversification is followed by changes in whole agriculture and also in agricultural trading. Higher portions of agricultural products remain in enterprises and this leads to a higher creation of value within agriculture. The number and the installed electrical power of biogas plants is stil rising now. At the end of 2005 there were about 50 biogas plants with an electrical power of 18 MW. It is estimated that 2010 there will be installed about 110 MW. This means an increase of about 600 % in a short period of 5 years. This increase in biogas plants will demand a higher amount of co- substrate crops. In 2010 we will need about 55,000 hectares of arable land for supplying biogas plants with co-substrates. Production of Biogas has become an important part of income from agriculture.

Biofuels in the Federal State Mecklenburg-Vorpommern The portion of rape seed is about 24 % of arable land and so it has reached a limit in crop rotation. About 140,000 hectares of rape seed are used for biodiesel production. It is not

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possible to increase the cultivation area of rape seed in Mecklenburg-Vorpommern. Nevertheless there is a rising demand on vegetable oil fuels. The biodiesel production capacity goes up to more than 400,000 tons at the end of this year (figure 1). This means theoretically that all rape seed yield of the federal state Mecklenburg-Vorpommern could be processed within Mecklenburg-Vorpommern.

Figure 1: Development of Biodiesel production capacity

450

400

350

300

250

200

150

100 Capacityfor biodiesel production (1000 t) 50

0 2000 2001 2002 2003 2004 2005 2006

Biodiesel is not the only biofuel on the basis of vegetable oil. It is also possible to use pure vegetable oils in special engines or mixtures of diesel and vegetable oil in series-production engines. At present about 5,000 tons of vegetable oil are used in Mecklenburg-Vorpommern.

Another biofuel is ethanol. It is made from the starch of cereals or from sugar of sugar beet. In future it will be also possible to produce ethanol from straw or other materials. At the moment Mecklenburg-Vorpommern is not able to produce ethanol fuel in an ethanol plant. But for instance the yield of 25,000 hectares of cereals is exported to Brandenburg. It is also planned to built a bioethanol plant in Rostock, where about 340,000 tons of cereals could be processed. That means an add-on demand of 50,000 hectares of cereals.

The fuel of the Future will be syntetic fuels made from each kind of biomass. Today they are not yet produced in plants but only in laboratories. If petroleum, coal and natural gas are not available any longer it is possible to save the rising demand of fuels with this BtL (Biomass

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to Liquid) and hydrogen fuels. An important advantage of BtL fuels is to process whole plants and not only parts like the grains. In this way it is possible to get higher yields of fuel per hectare. There are also plans to build a BtL plant in Mecklenburg-Vorpommern. It will have a capacity of about 200,000 tons of BtL fuel. Therefore 250,000 tons of wood and 250,000 tons of agricultural biomass will be necessary.

Solid fuels in the State Mecklenburg-Vorpommern Solid fuels are very important for heating houses and factories. There is a bold diversity of solid fuels but the calorific value of dry matter is not very different. The most important solid fuel is wood from forests. Especially waste wood is used as a fuel. About 100,000 tons of wood from forestry can be used every year. But it is also possible to grow wood on arable land. The yields of poplar are higher than the yields of willows under conditions of Mecklenburg-Vorpommern. Also straw of cereals is a valuable fuel. Regarding the demand of animal production and the needs of our soil fertility it would be possible to harvest the cereal straw of about 300,000 hectares. Till now it is not allowed to use the grains of cereals as a fuel. But it is estimated that cereals will take an important role in fuel supply of the future. There are also grasses which can be used as a fuel. Many hectares of green land are not necessary any longer for our animals. On arable land it is possible to grow grasses like miscanthus. We calculated a potential of grasses and similar biomass of about 55,000 hectares for utilization as a fuel.

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Conclusions Related on the year 2020 we have a technical potential of bioenergy production of 69 Petajoule. Nevertheless we will not be able to use up this potential. The rate of realization depends on the prevailing circumstances and on prices in the food sector compared with non food. Besides bold amounts of cereals and rapeseed are precessed and used outside Mecklenburg-Vorpommern. About 40 Petajoule could be really used inside Mecklenburg- Vorpommern to replace fossile energy (table 3).

Table 3: Use of biomass 2005 compared with estimation for 2020 (Petajoule)

Forecast of Kind of use Utilization 2005 utilization in 2020 Biogas 1,6 13 liquid Biofuels Biodiesel 1,7 3,7 vegetable oil fuel 0,2 0,9 Bioethanol 0 1,2 sum of liquid biofuels 1,9 5,8 solid fuels from agriculture 0 5 from forestry 13,2 16,8 sum of solid biofuels 13,2 21,8 sum of bioenergy 16,7 40,6

The production of bioenergy crops competes against production of food and feed. That´s why we estimate that about 345,000 hectares of arable land in Mecklenburg-Vorpommern could be used for energy crops in the year 2020. Furthermore the main part of all arable land will be needed to save nutrition of people and animals. The largest increase we expect in the field of biogas. Favourable conditions of payment because of the reneweable energy law support this development substantially. Compared with this there sure will be an extension of oilseed processing capacity but no increase of oilseed production area in Mecklenburg-Vorpommern. That´s why it is necessary to increase the yields per hectare. An important percentage of bioenergy will be exported and utilized outside of Mecklenburg- Vorpommern. The main parts within export will be biodiesel, cereals for ethanol production and BtL fuels. The percentage of bioenergy on primary energy consumption will rise from 10 % in 2005 up to 24 % in the year 2020 (figure 2).

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Figure 2: Development of portion of bioenergy on primary energy consumption in the state Mecklenburg-Vorpommern 2005 2020 other kinds of primary energy bioenergy

24 % 40,65 PJ

10 % 16,7 PJ

90 % 153,3 PJ

76% 129,35 PJ

furthermore net export 2005: 3,6 PJ furthermore net export 2020: 8,3 PJ

Bioenergy is an important factor of commerce within the state Mecklenburg-Vorpommern which has only little industries. But the raw material production already today plays an important role within german energy production. Compared with other states in Germany Mecklenburg-Vorpommern is able to replace a high part of primary energy by bioenergy.

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Remote Sensing and Modeling: A tool to provide the spatial information for biomass production potential

Günther, K. P. (1); Borg, E. (2); Wißkirchen, K. (1), Schroedter-Homscheidt, M. (1), Fichtelmann, B. (2)

German Aerospace Center (DLR), German Remote Sensing Data Center;(1) D-82237 Wessling, Münchnerstr. 20(2) D-17235 Neustrelitz, Kalkhorstweg 53, Germany

Abstract

Earth observation from space has been successfully demonstrated over a wide range of monitoring activities, mostly with the aim of measuring the spatial and temporal distribution of biophysical and geophysical parameters as e.g. the Normalized Difference Vegetation Index (NDVI), the land surface temperature (LST) or the land use classification (LCC). With the growing need for more reliable information of global biomass activity in the frame of climate change, the identification and quantification of carbon sinks and sources got of importance. The goal of our activities is to use time series of remote sensing data and carbon modeling to assess the biomass of large regions. Future activities will be discussed as reprocessing of archived time series (e.g. 30 years) of remote sensing data, which will be used as input to biomass modeling, improving the spatial resolution of local, historic land use maps by processing archived Landsat data (30m), using an innovative classification processor for deriving actual multi-temporal land use maps based MERIS data (300m) and delivering a biomass equivalent indicator as productivity indicator.

1. Introduction

Since the first oil crisis in 1973 the sustainable and economical use of energy is regarded as one of the most urgent tasks of mankind. Alternative energy resources like solar heating, photovoltaic, wind, water and biomass are taken into consideration besides the more efficient use of fossil energy resources. The use of biomass for heating has a long tradition. But a stable and continuous delivery of biomass for power generation as energy basis of a society needs a reliable spatial information system of the biomass production potential of a region, a country or state. At present statistical data as mean crop yield, timber volume, land use etc. are used to estimate biomass production. In combination with additional data (e.g. transportation net works and user), optimal locations for e.g. biogas plants can be identified. A new way for assessing biomass production potential is the combined use of satellite data and plant growth modeling. Operational utilization of satellite data in supporting an efficient and sustainable biomass production requires

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1. a comprehensive retrospective information basis of regional environmental parameters and 2. the availability of processing and modelling algorithms for assessing and quantifying the regional production potential of a region taking into account the effects of changes in land use.

A basis fulfilling the first requirement is given by the archived remote sensing data allowing the production of value added products of diverse environmental parameters (e.g. land use, leaf area index, fraction of absorbed photosynthetic active radiation) on regional basis, which influence the growing process of biomass. Additionally the second requirement is given by the existing operational semi-automated and automated processing chains for value adding remote sensing data at the German Remote Sensing Data Centre (DFD). To provide management information for existing biomass power stations the monitoring of the seasonal biomass productivity within a region is needed. Methods delivering environmental parameters which indicate the actual state of biomass in terms of seasonal growing status and spatial distribution are available at DFD. Also, automated multi-temporal classification processors are under development at the DFD. Based on this information, transport capacities and transport routes can be planned. Remote sensing can provide the fundamental parameters for the description of biomass growth. However, the essential parameter for the management of the power stations is the actual biomass yield. To derive this parameter, environmental simulation models are required which can assimilate value added remote sensing information for computing the actual biomass. A model fulfilling this requirement is given by the BETHY/DLR (Biosphere Energy Transfer Hydrology Model) [1,2]. The model can be used to analyze the biomass status for production regions of biomass power stations.

2. Remote sensing data

2.1 Land Cover Classification (LCC)

Up-to-date land cover information is needed for a wide range of applications including the estimation of biomass development. Thematic maps, such as land cover maps, can start with crude levels of classification, indicating for example merely the presence of vegetation, but can continue with increasing levels of class delineations.

Until recently, land cover mapping was a tedious manual process, and therefore not performed on a regular basis, or if so, was of very limited thematic and/or spatial accuracy. The use of image data collected with multi-spectral satellite sensors has, however,

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facilitated the timely and accurate production of land use/land cover maps of varying complexity. The complexity depends upon the ultimate application of the map, as well as on resource issues. A global or continental map cannot be as detailed as a map of a small area such as a county or state due, primarily, to the data resources required.

One example of a continental map product has resulted from the COoRdination of INformation on the Environment (CORINE) land cover initiative, described by Heymann [3] and Kiefl et al. [4]. This initiative is a challenging project of the European Commission, set into force in 1985 and updated in 2001 (CORINE 2000). Information on the European land use/land cover was and will continue to be derived by visual interpretation of Landsat TM/ETM+ and SPOT data augmented with ancillary information as e.g. topographic maps. The CORINE dataset currently covers the countries of the European Community (except Great Britain) and contains information on 44 land cover/land use classes (applicable to Europe) that are divided into three hierarchical levels.

Although a good product, the lag between CORINE updates is due to the manual nature of the techniques being utilized. One of the first European land cover/land use map projects based on semi-automatic processing of satellite data is the Pan-European Land Cover Monitoring project (PELCOM) a NOAA-AVHRR based LCLU map of Europe [5]. Multi- temporal AVHRR-NDVI data with a spatial resolution of 1 km were analysed using threshold techniques as well as additional data sources (e.g. Digital Chart of the World) for the identification of urban areas, wetlands and inland waters. 16 different classes are presented in the PELCOM data base. The mean accuracy is 69.2% [5]. In an effort to improve on this, two new classification methodologys for operational processing had been developed at the German Aerospace Center (DLR).

The first classification methodology is based on multi-spectral and multi-temporal MERIS data. In order to test this method, MOS data were applied in a first step. Ten-day maximum- value composites were generated to remove BRDF effects and to improve data quality. Then, an automated supervised maximum likelihood classification was performed on each composite by establishing a spectral database for all classes. These mono-temporal classification results were then merged to a single multi-temporal classification data set using a "voting" procedure. The accuracy of the resulting LCC map of Germany was assessed for using the CORINE land cover data as a reference. It was shown by Arndt et al. [6] that the classification results using this multi-temporal procedure were reliable, and exceeded the best available mono-temporal LCC maps in terms of accuracy and reliability.

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The basic concept of the second approach, which is patented now (Borg et al. 2002) [7], is the calculation of the phenological behaviour of a landscape object dependent on the multi- temporal spectral behaviour, assuming there exist a standardized phenological characteristic (figure 1). A landscape object can change its phenotype also by masking of dynamic processes (e.g. cloud and haze, snow, flood) with regard to its use and / or naturally annual variability.

The annual phenotype can be found out by a time series and contribute to the assessment of the use and use intensity as well as to the classification of the object (figure 2). If different years or different geographical zones are considered, temporal changes of the phenological vegetation circle can be established between the years. The phenotype of a landuse class is assumed to change over a scene in the phenological phenotype because of the geographical situation. It is also considered that changes of the sun position lead to a changed phenotype of the same object caused by the angular-dependent reflection qualities of the object.

R [ % ] λ [ nm ]

SoilVegetation, Clouds Soil, Snow t [ d ] Figure 1: Schematic Presentation of variation of spectral signature of a landscape object for a annual period, which is additionally disturbed by cloud cover and snow cover.

2.2 Vegetation Indices

For estimating biomass development using statistical procedures or modeling approaches, parameters related to the growth (phenology) and health of the plants are needed. The potential for gaining insight into the way vegetation changes over time and space is based on the knowledge of how reflected solar radiation is altered by the vegetation. Thus, sensors that acquire data in the visible and near-infrared (NIR) portions of the spectrum are utilized. Until recently, available remote sensing data sources have been satellite sensors with only a few spectral channels in the visible and NIR wavelengths. With sources such as these, only a rough estimation of plant parameters like the Normalized Difference Vegetation Index

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(NDVI) and more vivid the leaf area index (LAI) and/or fraction of absorbed photosynthetic active radiation (fAPAR) is possible [8]. The algorithms for making these estimations are empirical and rely on a simple relationship between the collected signal and plant parameter of interest. This simplification often leads to low accuracies. For example, an estimate of fAPAR

Remote Sensing Data (multi-temporal-multi-spectral)

Monotemporale Land Cover Classification Data Base Texture Analysis Spectral Analysis

Automatic Segmentation Land Cover Classes Automatic Land Cover Classification - Spectra Computation of the -Texture Classification Automatic Object Identification Accuracy

Multitemporal Data Reconstruction Temporal-Spatial Data Reconstruction

Quality Control

Multi-temporal Landuse Classification

Automatic Landuse Classification Landuse Classen - Spektra Modification of the Temporal Behaviour -Textures - Temporal Behaviour

Landuse Classes Figure 2: Flowchart of the automatically classification procedure used for identifying landuse classes and landuse intensity classes. based on this type of relationship can not distinguish between the absorption by photosynthetically active plant elements and the absorption by other plant material and soil.

However, the newest generation of sensors that have been recently launched as MERIS on ENVISAT with 300m spatial resolution have more spectral channels with better spatial resolution and better radiometric accuracy. With these sensors and the utilization of the different observation geometries of consecutive overpasses it is possible to apply various techniques to invert models describing the radiative transfer in vegetation. The models can consist of coupled leaf and canopy radiative transfer models as is the case with the PROSPECT and SAIL models described by Jacquemoud et al. [9] or of only a canopy

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component as is the model inversion scheme described by Bicheron & Leroy [10]. For the operational inversion of large amounts of data, the most useful techniques will be to apply lookup-tables (LUTs) or neural networks. The derivation of plant parameters by the inversion of radiative transfer models delivers a much more precise description of the vegetation. In addition to LAI, models have been developed which can derive parameters such as leaf angle distribution (LAD), chlorophyll content, and canopy height, as described by Weiss & Baret [11] and Knyazikhin et al. [12]. With this information it is possible to use forward radiative transfer models to calculate fAPAR with much higher accuracy than with the functional relationship described above.

For continental modeling of biomass LAI is processed (figure 3) using the operational NDVI product of DLR-DFD [13] which is calculated from data of NOAA-AVHRR. Spatial resolution of this data is 1.1 km. In order to reduce cloud contamination 10day composites are generated. A land cover based correction of solar zenith angel is applied to the NDVI. As land cover classification the NOAA-AVHRR based PELCOM classification is used [5]. Finally a time series analysis (harmonic analysis) is then applied to the NDVI data set in order to eliminate data gaps and outliers. Based on the smoothed NDVI time series, Fraction of Absorbed Photosynthetically Active Radiation (fapar) and LAI are calculated using the algorithm of Sellers et al. [8]. An example of the resulting LAI maps is given in figure 4.

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Figure 3: Flowchart of data processing for LAI time series.

2.3 Photosynthetically Active Radiation (PAR)

The solar energy reaching the earth within the wavelength region 400nm – 700nm is the driver of plant photosynthesis, and is thus often referred to as photosynthetically active radiation (PAR). In order to accurately model plant development and biomass development, PAR must be known. However, the use of ground truth measurements is often not suitable for an operational application, especially with regard to spatial resolution and temporal coverage. Thus, the use of remote sensing data and radiation transfer models, such as those based on theory described by Kato et al. [14], are being adopted at DLR in order to estimate PAR.

2.4 Land Surface Temperature LST

Among the variables that impact the development and use of biomass and which are taken into account in more sophisticated models, land surface temperature (LST) is one that can be derived from remotely sensed imagery as demonstrated by Becker and Li [15]. For models that do take LST into account, air temperature is often used as a proxy since surface measurements are rarely made on a regular basis. Even if available from a measuring

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station, the act of extending the LST ground truth point over large areas through interpolation introduces error. Using well-calibrated infrared imagery from the AVHRR sensor, DLR makes available an operational daily LST product [16].

Figure 4: Results of LAI calculation for the year 1998, 10day composite from day 18 to 190. Spatial resolution of the dataset is 1.1 km.

3. Modeling

The goal of our activities is to use time series of remote sensing data and carbon modeling to assess the biomass of large regions. At the German Aerospace Center (DLR) the mechanistic vegetation model BETHY/DLR (Biosphere Energy Transfer Hydrology Model) [1,2] is used to perform simulations of carbon exchange over Europe. The model is driven by remote sensing data of leaf area index (LAI) and land cover classification (LCC). Currently daily meteorological forcing data are given by data from the European Center for Medium Range Weather Forecast (ECMWF) in a spatial resolution of 0.5°.

Two versions of the BETHY/DLR model are used for simulations: One for simulations on regional scale with 1.1 km (exactly 1.132 km) resolution and one with reduced resolution (27.83 km) where the spatial resolution is aggregated for simulations on continental scale. The functional scheme of BETHY/DLR with data aggregation is shown in figure 5.

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3.1 Simulations on continental scale

For simulations on continental scale a data aggregation technique (DAG) is used to reduce resolution in order to keep the resolutions of input data compatible and to keep calculation time low. Original land cover and LAI data are aggregated to 25 by 25 pixel, resulting in a resolution of 27.83 km. For each land cover class the fraction of coverage area on the coarse grid is calculated. This information is used to calculate an area weighted average LAI for each class. Information on the coverage area is also used to calculate the overall sum of carbon uptake on each grid cell for each land cover class. Meteorological data from ECMWF are regridded using weighted area interpolation.

As an example results of annual net carbon uptake (NPP) on continental scale for 1998 are shown in figure 6 for coniferous forest and grassland. The most important structures of this land cover types are well identifiable, e.g. the coniferous forest region around Bordeux in France or the black forest and the Bavarian Forest in Germany. The grassland areas in Ireland and in the UK are also covered as well as the areas in the Benelux countries and in northern Germany.

Figure 5: Flowchart of data processing for the simulations with BETHY/DLR-DAG on continental scale.

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3.2 Simulations on regional scale

Data processing for regional simulations is performed by selecting subsets from the original datasets. For the application of the coarser resolved meteorological and soil data (0.5°) a simple tiling approach is used. Regional CO2 fluxes had been simulated for a 100 by 100 km subset around the permanent CO2-flux measurement station of Tharandt near Dresden/Germany (figure 7). The station is a part of the CARBOEUROPE-network [17] for the measurement of CO2 exchange between ecosystems and atmosphere. Data of this network are used for validation of the simulation results. Simulations were carried out for the year 1998. The Tharandt forest is located southwest of Dresden. High values of NPP correspond to forest areas while lesser values are mainly related to agricultural used areas.

3.3 Allocation scheme

The calculated NPP of a plant gives the amount of carbon which is stored by the plant. For quantifying the biomass which might be used as future energy resource a new modeling

Figure 6: NPP (TgC/a) for coniferous forest (left) and grasland ecosystems (right) approach must be taken into account, the resource allocation and growth partitioning. Most plants can modify their canopy architecture, crown shape or root distribution in order to favor their growth depending on the environmental conditions. If a detailed knowledge about nutrient and water supply as well as transport and utilization of resources is available. Yang & Midmore showed by a dynamic model that e.g. growth decision of individual shoot and root subunits depends on their local endogenous nutrient status [18].

From a simple point of view, woody plants can be identified by four tissue or carbon pools: leaf mass, sapwood mass, heartwood mass and fine root mass. Herbaceous plants and crops are treated much more simply by assuming the canopy as a “big leaf” characterized by

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the leaf mass and fine root mass only [19]. Based on the findings of Monteith [20] that there is a strong relation between the cumulative radiation quantity absorbed by the foliage during the cultivation period and the biomass production, Lobell et al. proposed a agro- meteorological model for estimating yield and thus biomass [21]. A sensitive parameter for this estimation is the harvest index which is given by Bastiaanssen & Ali [21] for some crops. As an example, several researches mentioned that the harvest index for cotton varies between 0.06-0.12 [23], 0.08-0.12 [24] and 0.12 [22].

Figure 7: Regional simulation result of NPP (gC/m2/y) for the region around the measurement station of Tharandt, near Dresden/Germany. Resolution is 1.1 km.

4. Conclusion

First results of NPP processing with the mechanistic model BETHY/DLR and satellite data as input are presented. LAI data are processed from NOAA-AVHRR based NDVI data using the algorithm of Sellers et al. (1996). For simulations on continental scale a data aggregation method is used while regional simulations are performed for limited areas in the original resolution of 1.1 km. Geographical distribution of NPP compares well to the distribution of the main land cover types.

Based on the modeling activity as well as on the operational processing of remote sensing data the German Remote Sensing Data Center will develop and improve its tools to quantify the biomass distribution of Europe. Future activities will include the reprocessing of archived time series (e.g. 30 years) of remote sensing data (mainly AVHRR data with 1.1 km spatial

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resolution), which will be used as input to biomass modeling. Also improving the spatial resolution of local, historic land use maps by processing archived Landsat data (30m) will help understanding European land cover change. In addition, using an innovative classification processor for deriving actual multi-temporal land use maps based MERIS data (300m) and delivering a biomass equivalent indicator as productivity indicator is planed for the future.

Acknowledgements

The work presented in this paper summarizes results of method and product development efforts of several years at DFD, partly in cooperation with it’s partners and customers. The authors wish to express special gratitude to the Max Planck Institutes for Meteorology, Hamburg, and BioGeo-Chemistry, Jena for their cooperation in the modeling field.

References

[1] Knorr, W., 1997: Satellitengestützte Fernerkundung und Modellierung des globalen CO2- Austauschs der Landvegetation: Eine Synthese. Dissertation zur Erlangung des Doktorgrades der Naturwissenschaften im Fachbereich Geowissenschaften der Universität Hamburg. [2] Wißkirchen, K., 2005: Modellierung der regionalen CO2-Aufnahme durch Vegetation. Dissertation, Meteorologisches Institut der Rhein. Friedr.-Wilh.-Universität Bonn, 129 S. [3] Heymann, Y. 1994: CORINE Land Cover Technical Guide, Tech. Rep. EUR 12585 EN, European Commission. [4] Kiefl, R., Keil, M., Strunz, G., Mehl, H. & B. Mohaupt-Jahr, B. 2003: CORINE Land Cover 2000 - Stand des Teilprojektes in Deutschland. In: Strobl, J., Blaschke, T. & Griesebner, G. [Hrsg.] (2003): Angewandte Geographische Informationsverarbeitung XV. Beiträge zum AGIT-Symposium Salzburg 2003, Wichmann Verlag, 202-207. [5] Mücher, C.A., Steinnocher, K., Kressler, F., & C. Heunks, 2000: Land cover characterization and change detection for environmental monitoring of pan-Europe. International Journal of Remote Sensing, Vol. 21, Nr. 6 - 7, pp. 1159 -1181. [6] Arndt, M., Guenther, K.P. & S.W. Maier, 2001: Deriving Land Cover Information from multi-temporal MOS Data 4th Berlin Workshop on Ocean Remote Sensing, “5 years of MOS-IRS”, eds. Remote Sensing Technology Institute, DLR, Wissenschaft und Technik Verlag, pp. 205 – 215. [7] Borg, E.; Günther, K.-P.; Maier, S.W.; Fichtelmann, B. (2003): Verfahren und Vorrichtung zur mindestens teilweise automatisierten Auswertung von Fernerkundungsdaten. – Deutsches Patent Nr. 103 58 938.- 12 S. [8] Sellers, P.J. et al., 1996: A revised land surface parametrization (SiB2) for atmospheric GCM’s. Part II: The generation of global fields of terrestrial biophysical parameters from satellite data. Journal of Climate, Vol. 9, pp. 706-737. [9] Jacquemoud, S., Baret, F., Andrieu, B., Danson, F.M. & K. Jaggard, 1995: Extraction of vegetation biophysical parameters by inversion of the PROSPECT+SAIL models on sugar

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beet canopy reflectance data: Application to TM and AVIRIS Sensors. Remote Sensing of the Environment, 52, pp. 163-172. [10] Bicheron, P. & M. Leroy, 1999: A method of biophysical parameter retrieval at global scale by inversion of a vegetation reflectance model. Remote Sensing of the Environment, 67, pp. 251-266. [11] Weiss, M. & F. Baret, 1999: Evaluation of canopy biophysical variable retrieval performances from the accumulation of large swath satellite data, Remote Sensing of the Environment, 70, pp. 293-306. [12] Knyazikhin., Y., Martonchik, J., Diner, D., Myneni, R., Verstraete, M., Pinty, B. & N. Gabron, 1998: Estimation of vegetation canopy leaf area index and fraction of absorbed photosynthetically active radiation from atmosphere-corrected MISR data. Journal of Geophysical Research, 103(D24), pp. 32,239-32,256. [13] Dech, S., Tungalagsaikhan, P., Preusser, C., & R.E. Meisner, 1998: Operational value- adding to AVHRR data over Europe: methods, results, and prospects. Aerospace Science and Technology, 5, pp. 335-346. [14] Kato, S., Ackerman, T.P., Mather, J.H. & E.E. Clothiaux,1999: The k-distribution method and correlated-k approximation for a shortwave radiative transfer model. Journal of Quantitative Spectroscopy & Radiative Transfer, 62, pp. 109-121. [15] Becker, F. & Z. Li, 1990: Towards a local split window method over land surface. International Journal of Remote Sensing, 3, pp. 369-393. [16] Tungalagsaikhan, P., Meisner, R. & S. Dech, 1998: Operational generation of AVHRR- based Land Surface Temperatures (LST) - A new value adding product from the German Remote Sensing Data. Proceedings of the 1998 International Geoscience and Remote Sensing Symposium IGARSS´98, 6-10 July, Seattle, USA, pp. 2116 – 2118. [17] Valentini, R. (Ed.), 2000: The Euroflux dataset 2000: In: Carbon, water and energy exchanges of European forests. Springer Verlag, Heidelberg, pp 300. [18] Yang, Z. & Midmore, D. J., 2005: Modelling plant resource allocation and growth partitioning in response to environmental heterogeneity. Ecological Modelling, 181, pp. 59- 77. [19] Sitch, S., Smith, B., Prentice, I.C., Arneth, A., Bondeau, A., Cramer, W., Kaplan, J.O., Levis, S., Lucht, W., Sykes, M.T., Thonicke, K. & S. Venevsky, 2003: Evaluation of ecosystem dynamics, plant geography and terrestrial carbon cycling in the LPJ dynamic global vegetation model. Global Change Biology, 9, pp. 161-185. [20] Monteith, J. L., 1977: Climate and the efficiency of crop production in Britain. Phil. Trans. Roy. Soc. Lond. B, 281, pp. 277-294. [21] Lobell, D.B., Asner, G.P, Ortiz-Monasterio, J.I. & T.L. Benning, 2003: Remote sensing of regional crop production in the Yaqui Valley, Mexico: estimates and uncertainties. Agriculture, Ecosystems and Environment, 94, pp. 205-220. [22] Bastiaanssen W. G. M. & S. Ali, 2003: A new crop yield forecasting model based on satellite measurements applied across the Indus Basin, Pakistan. Agriculture Ecosystems and Environment, 94, pp. 321-340. [23] Sys, I. C., Van Ranst E. & Ir. J. Debaveye, 1991: Land evaluation, Part I. Agricultural Publication-N° 7, General administration for development cooperation, Brussels, Belgium. 146p. [24] FAO. 1979: Yield response to water. Irrigation and drainage paper. No 33. Rome Italy.

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Prediction of potential productivity of perennial C4 grasses in Poland by means of physiological model (concepts and methodology)

*D.Sc. Robert Maciorowski, M.Sc. Katarzyna Kołtoniak Department of Biometry, Agricultural University of Szczecin, Szczecin, Poland

Abstract In this paper the methodology of the potential productivity modeling of M. sinensis Anderss., M. sacchariflorus (Maxim.) Benth. et Hook. and P. virgatum L. throughout Poland is presented. The physiological empirical model is parameterized on a base of the field trials data.

1. Introduction The European Union (EU) focuses its attention on minimising of the greenhouse effect through the reduction of CO2 emitted into the atmosphere. One of the reduction ways is the greater use of renewable energy sources such as biomass. According to Venedall et al. [1] different types of biomass sources may be taken into consideration such as; woody, herbaceous, oil and sugar crops. Many different plants are being considered for this purpose from each group. The most promising plants seem to be the perennial rhizomatous grasses with the C4 photosynthetic pathway. One of them is the genus Miscanthus Anderss. originating from Southeast Asia [2]. This genus includes Miscanthus x gigantheus Greef et Deuter, the most cultivated species with respect to biomass production across Europe. The field trial data indicate high biomass yield potential amounting to 25 t⋅ha-1 onwards the third year of cultivation and the great variation of yield depending on the climatic conditions. These trials have shown also agronomic advantages and limitations of M. x gigantheus cultivation. According to Lewandowski et al. [3], the agronomic advantages are: high yield; low fertilizer and pesticide input. The key limitations are: relatively high planting cost, narrow genetic base, and low hardiness in the first winter following the establishment of plantation. Particularly, this last constrain and the requirements for warm conditions to initiate vegetation in spring restrict the cultivation of M. x gigantheus in the Eastern part of Poland. The genus Miscanthus Anderss. includes the two other genotypes such as Miscanthus sacchariflorus (Maxim.) Benth. et Hook. and Miscanthus sinensis Anderss. Very important advantage of M. sinensis genotypes over M. x gigantheus is their improved winter hardiness [4]. The data from the field trails in Denmark [5] indicate that M. sinensis clones can out-yield M. x gigantheus genotypes.

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Switchgrass (Panicum virgatum L.) is a warm season perennial herbaceous C4 grass that is indigenous to North America and is found from Mexico to Canada. Compared to M. x gigantheus, switchgrass is smaller, thinner and generally leafier [6]. Switchgrass is established from seed and for that reason the start cost of cultivation is less expensive and involves less risk than that of Miscanthus, which is propagated by rhizomes. Switchgrass is more drought tolerant and growing better under low fertility (low input) conditions. The data from European field trials with wide range of varieties originating from North America showed that yielding of switchgrass in different climatic conditions is highly depended on the place of origin of the particular variety. For NW European areas the upland varieties have given better results than lowland genotypes [7].

There is a lack of data describing growth and yielding of C4 perennial grasses in different growing regions in Poland. The existing data are mainly derived from microplot experiments, observations from botanical gardens or collections that have been done on single plants [8, 9]. The comparative study of M. sinensis clones (Goliath, Hybriden) and M. x gigantheus (clone 53 from Germany, clone 63 from Denmark and POL from Poland) indicates that in the Middle East region of Poland M. sinensis clones out-yielded clones of M. x gigantheus, in the third year of vegetation [10]. Our data [11] from Western Pomerania region of Poland concerning M. sinensis and Panicum virgatum (v. Cave-in-Rock) indicate high biomass yield potential up to 10 t⋅ha-1 of M. sinensis and 8.0 t⋅ha-1 of P. virgatum. However, harvested amount of biomass varied and depended strictly on winter conditions and the term of vegetation starting in spring.

In the last few years some initiatives have been undertaken to model a potential yields of C4 perennial grasses in different European countries. Some of those studies are based on physiological models with implementation of the meteorological data [12]. Other predict potential farm levels yield on the basis of the recalculated data from the field plot trials [13].

In 2006 an integrated project of the Agricultural University of Szczecin and the “Dolna Odra” Power Plant has been undertaken. The general objective of this work is the evaluation of potential biomass productivity of M. sinensis, M. sacchariflorus and P. virgatum throughout Poland on the basis of empirical model and the regional meteorological data. This general goal has been divided into specific four objectives:

1. Collection of physiological data to explain biomass accumulation during three growing seasons.

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2. Parameterisation of the physiological model at the assumption that nutrients supply are non-limiting for crop growth. 3. Scaling of the model countrywide. 4. Preparing of digital visualization model on the basis of geographic information system.

2. Materials and methods 2.1. Experimental design and treatments The research is conducted at the Dolna Odra Power Plant in Nowe Czarnowo (53º12’N; 14º27’E) on the experimental model consisting of the separated plots. Plants are growing on the artificial layers consisting of the underlying (2 m deep) ash-slag layer covered with 0.4 m deep organic layer*, (* - mixture of the coniferous bark, the loose sand, the compost produced by GWDA method and the ash-slag, at the proportion 1:1:2:4). The physical and chemical properties of substratum are presented in Tab. 1. The seedlings of M. sinensis and M. sacchariflorus have been planted in 2004 at the density of two plants⋅m-2. In the same year, Panicum virgatum v. Cave-in-Rock has been sown at the seeding rate 15 kg⋅ha-1. At the beginning of each growing season mineral fertilizers have been applied at 80 kg N·ha-1, 40 kg P·ha-1, 60 kg K·ha-1. The weeding is controlled manually. Table 1.

Property Upper layer (0-40 cm) Underlying layer (below 40 cm) Physical properties Bulk density [g·cm-3] 1.03 1.04 Capillary porosity [%] 49.40 52.00 Non-capillary porosity [%] 3.21 7.25 Chemical properties pH reaction in 1M KCl 7.3 8.9 Organic matter [%] 7.7 0.19 Total N [g N⋅kg-1 d.m.] 1.73 1.01 Total P [g P⋅kg-1 d.m.] 1.08 25.1 Available P [mg P⋅kg-1 d.m.] 37.3 6.23 Total K [g K⋅kg-1 d.m.] 5.15 27.4 Available K [mg K⋅kg-1 d.m.] 55.6 0.20 Total Mg [g Mg⋅kg-1 d.m.] 1.15 11.2 Available Mg [mg Mg⋅kg-1 d.m.] 23.6 8.9

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2.2. Plant sampling Starting from the beginning of the vegetation season (2006) at two week intervals 20 shoots of each species are harvested. Plants are separated into leaves, stems and inflorescences. The assimilation area is measured using the DIAS (Delta-T Devices, Cambridge, UK); then plants are oven-dried at 80 oC and weighted. At each term of sampling, the number of shoots⋅m-2 is evaluated, and on this basis the LAI is calculated.

2.3. Canopy PAR transmission At two week intervals the incident, transmitted and reflected PAR radiation above and at the ground level of the canopy are measured by means of quantum sensor LI-190 SA (LI-Cor, Lincoln, USA) combined with linear PAR ceptometer PAR-80 (Decagon Devices, Pullman, USA). On the 10 randomly sampled leaves the chlorophyll fluorescence measurements are done using PEA Fluorymeter (Hansatech Instruments, King’s Lynn, UK).

2.4. Meteorological data collection at the trial location Air temperatures at 2 hour intervals are measured and recorded using a datalogger Em50

(Decagon Devices, Pullman, USA). The soil moisture is monitored by means of ECH2O probe model EC-5 combined with the same datalogger. Daily incident PAR is measured at 2 s intervals using quantum sensor PAR LITE (Kipp&Zonen B. V., Delft, The Netherlands) and the summarized daily data are stored in datalogger Solrad Integrator Kipp&Zonen B. V., Delft, The Netherlands). Data concerning precipitation are taken from the meteorological station of Dolna Odra Power Plant.

3. Model description The model of potential biomass productivity is based on the empirical model of Monteith [14]:

Wh = St ⋅ei ⋅ec (1)

In Eq. 1 the dry matter at harvest (Wh) is the result of the integral of incident solar radiation

(St), the fraction of radiation that is intercepted by the canopy (ei) and the efficiency of the conversion of the solar radiation into biomass (ec).

The concept of our model partially based on data and experiences stored by Clifton-Brown et al. [12] which predicted M. x gigantheus biomass productivity across Ireland.

Thermal leaf area coefficient (ti) will be obtained by regression analysis of LAI versus accumulated degree days above a base temperature (DDTBX).

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Radiation extinction coefficient (k) will be derived from the relationship between ei and the LAI according to Eq. 2 [15]:

k = (exp(ei −1)) / LAI (2)

Radiation use efficiency (ec) will be obtained from regression of the dry matter and canopy intercepted radiation. The influence of water and light stress on the ec will be evaluated by means of the chlorophyll fluorescence technique according to Strasser JIP test method [16].

According to Clifton-Brown et al. [12], the length of the vegetative season will be taken as a number of days between the last spring and the first autumn air frost (0oC terminal air temperature).

The model will be parameterised for water limiting and non-limiting conditions.

4. Meteorological data and surface digitalization of the model Daily sunshine hours, maximum/minimum air temperatures for the minimum 30 stations across Poland will be obtained from the Institute of Meteorology and Water Management. Those data will be incorporated into the geographic information system (GIS, IDRISI, Clarke University, Massachusetts, USA) to produce digital presentation of the model.

5. References [1] Venendaal, R.; Jørgensen, U.; Foster, C.A.: European energy crops: a synthesis, Biomass & Bioenergy 13, pp. 147-185, 1997 [2] Atienza, S. G.; Satovic, Z.; Petersen, K. K.; Dolstra, O.; Martin, A.: Identification of QTLs influencing agronomic traits in Miscanthus sinensis Anderss. I. Total height, Flag-leaf height and stem diameter, Theoretical Applied Genetics 107, pp. 123- 129, 2003 [3] Lewandowski, I.; Clifton-Brown, J.C.; Scurlock, J.M.O.; Huisman, W.: Miscanthus: European experience with a novel energy crop, Biomass & Bioenergy 19, pp. 209- 227, 2000 [4] Scurlock, J.M.O.: Miscanthus: a review of the European experience with the novel energy crop, Oak Ridge National Laboratory Report, pp. 1-15, 1999 [5] Jørgensen, U.: Genotypic variation in dry matter accumulation and content of N, K and Cl in Miscanthus in Denmark, Biomass & Bioenergy 12, pp. 155-169, 1997 [6] Christian, D. G.; Elbersen, H.W.; El Bassam, N.; Sauerbeck, G.; Alexopoulou, E.; Sharma, N.; Piscioneri, I.; de Visser, P.; van den Berg, D.: Management guide for

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planting and production of switchgrass as a biomass crop in Europe, Switchgrass (Panicum virgatum L.) as an alternative energy crop in Europe, Final Report, pp. 72-75, 2002 [7] Elbersen, H.W.; Christian, D. G.; El Bassam, N.; Bacher, W.; Sauerbeck, G.; Alexopoulou, E.; Sharma, N.; Piscioneri, I.; de Visser, P.; van den Berg, D.: Switchgrass variety choice in Europe, Switchgrass (Panicum virgatum L.) as an alternative energy crop in Europe, Final Report, pp. 35-41, 2002

[8] Majtkowski, W.: Przydatność wybranych gatunków traw typu C4 do upraw alternatywnych w Polsce, Hodowla Roślin i Nasiennictwo 2, pp. 41-44, 1998 (in Polish) [9] Jeżowski, S.: Rośliny energetyczne – produktywność oraz aspekt ekonomiczny, środowiskowy i socjalny ich wykorzystania jako ekopaliwa, Postępy Nauk Rolniczych 3, pp. 61-73, 2003 (in Polish) [10] Kalebasa, D.; Malinowska, E.; Jaremko, D.; Jeżowski S.: Wpływ nawożenia NPK na strukturę plonu traw Miscanthus ssp., Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin 234, pp. 205-218, 2004 (in Polish) [11] Tomczewska, J.; Maciorowski, R.; Stankowski, S.: Productivity of Miscanthus sinensis Anderss. and Panicum virgatum L. plants growing on the reclamated areas, Book of proceedings Part II, IX ESA Congress 4-5 September 2006, Warszawa, Poland, pp. 721-722, 2006 [12] Clifton-Brown, J.C.; Neilson, B.; Lewandowski, I.; Jones, M. B.: The modeled productivity of Miscanthus x gigantheus (GREEF et DEU) in Ireland, Industrial Crops and Products 12, pp. 97-109, 2000 [13] Elbersen, H. W.; Bakker, R.R.; Elbersen, B.S.: A simple method to estimate practical field of biomass grasses in Europe, Proceedings of the 14th European Biomass Conference, Biomass for Energy, Industry and Climate Protection, 17-21 October 2005, Paris, France, pp. 1217-1221, 2006 [14] Monteith, J.L.: Climate and the efficiency of crop production in Britain, Philosophical Transaction of the Royal Society of London B281, pp. 277-299, 1977 [15] Monsi, M.; Saeki, T.: Über den Lichtfaktor in den Pflanzengesellshaften und seine Bedeutung für Stoffproduktion, Japanese Journal of Botany 14, pp. 22-25, 1953 [16] Strasser, B.J.; Strasser, R.J.: Measuring fast fluorescence transient to address environmental questions: The JIP test, In: Photosynthesis: from light to biosphere, Ed. P. Mathias, Kluver Academic Publishers, Dodrecht, pp. 977-980, 1995

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Solid Biofuels from the Plantation on the Fallow Soil

prof. nadzw. dr hab. Michał Jasiulewicz Economics and Management Department, Koszalin University of Technology, Koszalin, Poland

Summary

EU indicates a need to increase renewable energy production, including biomass usage. Practical and theoretical solutions related to the biomass usage require close cooperation of science and economy. Fallow grounds shares of arable lands in Poland are high: 10%. Also marginal grounds (LFA) used for agriculture production i.e. consumable food products represent a significant part – about 40%. Utilizing such lands in EU countries for energetic plants cultivation creates a great opportunity. LFA and fallow grounds are good for growth of willow, rose and miscantus because of their low soil requirements.

The biomass should be used in local power stations in little towns and hot water should be used for heating. Creation of a net of power and heating stations should influence the climate and safety of electricity and heating. It will develop job places in rural areas and little towns, too. In result, sustainable entrepreneurial development of regions is expected.

Introduction

Biomass is one of the most promising energy sources in EU, particularly in Poland. Arguments of the EU access contract indicate a need of increasing renewable energy production, including raw materials based on biomass usage. There are many solutions of issues related to the usage feasibility of biomass.

Biomass energy has been recognized as one of the most promising and most important renewable energy sources in near future for Polish conditions.

The total technical potential of biomass resources has been calculated at 755 PJ (EC EBMER, 2005).

The largest resources are related to the agricultural residues, forestry residues and forestry fuel wood. Energy crops and willow plantations will play more important role in mid- and long-term perspective.

It could be produced in sufficient quantity on the whole area of the country, hardly having any competition. The electric energy sector in Poland is based in 97% on coal, as nowhere else.

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About 65% of the district heat in Polish towns is provided by centralized installations, which supply annually 270 to 300 PJ of heat energy (T.Golec, A.Grzybek, Experience with biomass district heating in Poland, 2005). Majority of heat is produced from coal. At present, installed power of biomass – fired heating systems – can be estimated at about 1 GW. According to current forecasts, it is expected to increase up to 10 GW until 2010 y. Thus, initiatives aiming at renewable energy sources may be almost unlimited. Feasibility of production and usage of biomass for power and thermal energy production seems to be unlimited as well.

Possibility of Energetic Plants Cultivation

Biomass is one of the most promising energy sources in Poland. Biomass energy has been recognized as a most promising and most important renewable energy source in near future for Polish conditions. Local climatic conditions, low quality of soils and free manpower in the rural areas create a unique opportunity to cultivate energetic plants to be used in energy production process. The energetic usage of cultivated plants in a communal heating plant addresses directly the Priority Thematic Areas in EU of Sustainable development, global change and ecosystems. First of all, it fits into aiming at alteration of the European energy sector structure – in this specific case via the biomass production from cultivated energy plants, that would lead to increase the percentage of energy production from the renewable energy sources. The proposed solutions, after their implementation, will contribute to lowering harmful components of the fuel fumes, resulting in positive influence on the environmental protection. The sustainable energy system shall be included into the chain of the energy supply. It is very important not only to lower cost of the currently used conventional fuel and influence the environmental protection but also to enhance spreading methods of bringing little useful land into agricultural cultivation. There is social context attached to this point, related with an increase of economical interest in rural areas, associated with a partial increase of employment. From this perspective it may be expected that the project solutions own a defined competitive dimension in comparison with current conventional energy sources. Presented technological solutions have a very multidisciplinary character as they take into account the whole chain from preparing the land and planting up to their energetic usage in a communal heating plant.

Arguments of the EU access contract indicate a need of increasing renewable energy production, including this from raw materials based on biomass usage. Practical and theoretical solutions of issues related to the usage feasibility of biomass, in its various forms and kinds of plants, requires close co-operation of science and economy in the most efficient way. In most of the EU member countries, as in Poland, a significant surplus of agricultural

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products, of which production, storing and export subvention cost constitute large amounts in EU and countries budgets. Percentage of fallow grounds in relation to the arable lands in Poland is high – about 10%, and on West Pomeranian voivodeship – 27%. Also marginal grounds (LFA) used for agriculture production i.e. consumption food products, represent a significant part. Thus, utilising such land, in Poland or in other EU countries, for energetic plants cultivation (willow etc.) of relatively low soil requirements, for which LFA and fallow grounds are enough for growth, creates a great opportunity to utilise the non-used by now land. An increasing issue in EU and world scale is a fast increase of communal refuse and sewage residues, as well as the problem of their neutralisation. There are many not solved or not fully verified research problems related to the biomass: production, manure with sewage residues communal refuse, co-combustion with coal, turning it into gas.

The Research Project

The teams will jointly run experiments and implement new technologies and results of the scientific research. The activity, common work of science and practice, constitutes a very important element of the project, i.e. implementation of the latest research achievements into economy. In case of necessity and special needs, it is expected to use distinguished specialists, institutes and implementation companies, both Polish and from other countries. This would lead to use the latest scientific and implementation achievements. In the project there are many results from various disciplines expected to be achieved, among others: • Utilising of the sewage residues and communal organic refuse as manure on the plantation. • Selection of plants of the most efficient growth and energy results, taking into account technical, environmental, economical aspects. • Finding solutions of many technical, technological and economical issues of the co- combustion of coal with the biomass. • Description of utilisation of the thermal energy surplus for power production, as an effect of turning the biomass into gas. • Converting a communal heating plant into heat and power generating plant based on the biomass as a raw material. • High biomass demand would ensure using the marginal soils (LFA) and guarantee continuity of supply and power production. Such effect should contribute for creation of many work-places in the rural areas (production, harvest, transport) and their activation, utilisation of the fallow grounds. Small and medium local heat and power generating plants will be created, ensuring energetic self-sufficiency.

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The project includes complex research related to using the biomass as energetic raw material, i.e. from cultivation of the energetic plants, manure with residues from purification plant and from communal dumping grounds, trough caring, harvest, transportation, preparation for processing, to usage as an energetic source (co combustion, turning into gas). Implementation of the scientific research and experiments into practical usage of the biomass for production of thermal energy and power should stimulate for common utilisation of the fallow grounds and other LFA grounds and for setting energetic plants plantations.

Koszalin University of Technology has founded in 2005y a new plantation of willow on the fallow areas 31,5 ha. After the summer time in November 2005y all of the shoots has been cut. In 2006y it was really the first year of the rise for the biomass – what is the thickness, height, average number of shoots and rate of willow’s rise-you can see in the tables 1, 2, 3, 4, 5.

Tab.1: Average number of shoots in one rhizome in 2006y 1013 1047 1052 1054 1023 Clone 1047D Date of measurement 31.05.2006 17,1 20,7 16,7 15,5 17,7 14,4 09.06.2006 11.8 13,2 12,4 11,8 14,5 11,6 19.06.2006 10,5 11,6 10,0 9,8 10,2 10,1 30.06.2006 8,2 10,3 5,6 7,7 6,7 6,5 17.07.2006 6,4 7,1 5,2 5,8 5,7 6,0 01.08.2006 5,4 6,8 4,8 5,3 5,3 5,5

Source: Own research

Tab. 2: Average number of shoots in one rhizome (1.08.2006y) 1047D 1013 1047 1052 1054 1023 Clone Manure „0” 5,5 6,0 4,5 5,0 5,5 5,0 0 1 5,0 6,0 5,0 5,0 5,5 5,8 0 2 6,5 8,0 5,0 6,2 5,5 5,8 M 1 5,0 7,2 4,6 5,2 5,0 5,0 M 2 5,0 6,8 4,8 5,2 5,0 6,0

Source: Own research

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Tab. 3: Average rate of willow’s rise in 2006y (cm) 1047D 1013 1047 1052 1054 1023 Clone Date of measurement height 69,9 49,1 77,0 64,9 70,2 60,5 31.05 Daily growth 2,2 1,6 2,5 2,1 2,7 1,9 height 89,6 64,7 95,7 85,2 94,4 87,1 09.06 Daily growth 2,2 1,7 2,1 2,3 2,7 2,9 height 116,4 92,6 142,6 124,8 141,2 119,8 19.06 Daily growth 2,6 2,9 4,7 3,9 4,7 3,3 height 152,8 136,0 167,8 146,4 175,0 142,6 30.06 Daily growth 3,3 3,9 2,3 1,9 3,1 2,1 height 177,8 157,4 206,8 154,4 198,4 152,6 17.07 Daily growth 1,5 1,2 2,3 0,5 1,4 0,6 height 189,0 166,0 215,2 158,0 210,0 161,0 01.08 Daily growth 0,8 0,6 0,6 0,2 0,8 0,4

Source. Own measurements and calculation

Tab.4: Average height of shoots in cm (01.08.2006y) Clone 1013 1047 1052 1054 1023 1047D Manure „0” 160 150 200 140 170 150 0 1 190 160 201 155 220 160 0 2 200 180 225 160 220 165 M 1 195 170 220 160 220 160 M 2 200 170 230 175 220 170

Source: own research

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Tab.5: Average thickness of shoots in mm (01.08.2006y) Clone 1047D 1013 1047 1052 1054 1023 Manure „0” 8,0 7,0 10,2 7,5 9,5 8,0 0 1 9,5 7,0 10,0 8,5 9,9 9,5 0 2 9,7 8,0 10,5 9,0 11,5 9,0 M 1 10,0 8,0 11,0 9,0 10,5 8,4 M 2 9,0 8,0 11,5 10,5 9,8 8,0

Source: own research

The produced biomass should be used in local heat and power generating plants that may supply the local environment with thermal energy, and the surplus should be converted into electric power and supplied to the country power network. Following this pattern the local systems would be self-sufficient in the energy meaning. Many new non-agricultural workplaces will be created in the rural areas. This activity will improve their social status, being a source of additional incomes. The state of environment in the rural areas (water, soil, atmosphere) should get significantly improved as well. The activity – disseminated on a large scale – should be an important factor of the rural areas activation, especially, in areas of low agri-cultural value and high unemployment. The activity co-ordinated by the project through its implementation to the economy should enable to all interested not only using the results of the research but also getting through information and seeing the full production cycle, i.e. from planting seedlings up to the final product – thermal energy and power generation (co-combustion with the coal, turning it into the bio-gas and conversion into thermal and electric energy). It may become an important factor of low developed regions. Implementation of the energy production based on the biomass would give a great chance to the whole West Pomeranian voivodeship and to other areas of Poland and other member of EU in activation for development.

Farmers are an important target group of the project results implementation and demonstration. Currently they are highly interested in the biomass production, however lack of its utilisation possibilities makes organising the production on an industrial scale hardly feasible. The demonstration activities directly on the energetic plantation has a significant meaning, according to the project group. They will be lead in various phases of vegetation, harvest, and during the biomass conversion.

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The research results, including verified new technologies of combustion, co-combustion, and the turning the biomass into gas, will significantly affect current thermal energy producers with the issue of gaining energy from the biomass.

The project group, the consortium ensures transmitting the results into the energy sector, represented in the West Pomeranian voivodeship by a number of small and medium heating plants producing thermal energy for local market purposes. Conversion of the plants into heat and power generating plants based on the biomass will influence activation of the rural areas and small towns through creation of new workplaces and a real vision of the region development.

Conclusions

Thus, utilizing such land, in Poland or in other EU countries, for energetic plants cultivation (willow, rose, miscantus, etc.) of relatively low soil requirements, for which LFA and fallow grounds are enough good for growth, creates a great opportunity to utilize the non – used land now.

The biomass should be used in the local power stations in the little towns and hot water should be used to the heating local flats. Creating the net of power stations and heating should cause not only the influence on the climate and safety of electricity and heating but first of all it cause the development of the rural areas and little towns, many SME s and job places. It’d caused sustainable entrepreneurial development regions.

Bibliography • Rural Development in the Enlarged European Union, Editor: K. Zawalińska, Institute of Rural and Agricultural Development Polish Academy of Sciences, Warsaw, 2005 • Jasiulewicz M. Feasibilities of Marginal Soils Usage by Energetic Plants Cultivation in West Pomeranian Voivodeship, [in:] World Agricultural Issues. Vol. 12 Current Trends in International Economy Relations in Agriculture and Food Economy, Publishing House of the Main Farming University, Parts 3 and 4, Warsaw 2004 • Jasiulewicz M., Fijałkowska E.: Importance of Energetic Plants Cultivation in the Multifunctional Development of the Rural Areas in Western Pomeranian, [in:] Contemporary Conversions and the Future of the Polish Country edited by: B. Górz, Cz. Guzik, Rural Areas Study, Vol. 4, Polish Academy of Sciences Institute of Geography and Spatial Organization in Warsaw, Warsaw 2003

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Author Information

Prof. Michał Jasiulewicz Ph..D., D.Sc. Koszalin University of Technology 75-453 Koszalin, ul. Sniadeckich 2 Poland Tel: +4894 34 78 602 Fax: +4894 34 78 668 e-mail: [email protected]

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Lignocellulosic energy crops – four years’ experiences from National Centre for Renewable Energy in Grimstad, Norway

Prof. Dr. Henrik Kofoed Nielsen* (1), M.Sc., Dipl.-Wirtsch.-Ing.(FH), Martin Kunze(2), Prof. Dr.–Ing., Matthias Ahlhaus (3)

(1) Agder University College, Grimstad, Norway (2) Offenburg University of Applied Sciences, Offenburg, Germany (3) Stralsund University of Applied Science, Stralsund, Germany

1 Introduction In 2002 an area of 0.15 ha was established with the two following lignocellulosic energy crops; elephant grass, Miscanthus x giganteus, and reed canary grass, Phalaris arundinacea 'Bamse'. In 2006 an additional crop a sorrel hybrid, Rumex patientia x Rumex tianschanicus 'Rumex OK-2' was established. The area and establishing data are shown in table 1. While elephant grass and reed canary grass are known in the Nordic countries, this sorrel hybrid has only been introduced a very few places. Sorrel is a perennial, which can be harvested dry continuously in the summer with high yields for more than 10 years [1]. In figure 1 a photo of our sorrel with reed canary grass behind, left is shown.

Table 1. Description of the establishment of lignocellulosic energy crops in Grimstad. Autumn 2004 the remaining elephant grass plants were moved into a single row, 50 m long. Established Year Form Area First harvest Elephant grass 2002 10900 rhizomes ha-1 750 m² 2003 May Reed canary grass 2002 30 kg seeds ha-1 750 m² 2004 March Sorrel 2006 11 kg seeds ha-1 90 m² 2007 July/August

Figure 1. Sorrel sowed May 16 and photographed October, 4th 2006. Sorrel will first run into seeds the second summer and the flower stalk will grow up to 2.60 m according to [1]. The highest leave in the picture is 66 cm high.

The area with all three crops is fertilized, but not sprayed or irrigated. The mean precipitation is 1230 mm and medium annual mean temperature is 6.9 ºC [2]. The soil is medium sandy

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with clay content about 5%. To achieve a better soil structure 5 cm of composted sewage sludge and sawdust was harrowed in prior to establishment in 2002, and mould content is stabilized to 3.0-4.5 %. The subsequent years mineral fertilizer with up to 85 kg N per ha was applied. The amounts are listed in table 2, where the fertilization effect of compost is stated as available nutrients the first year.

Table 2. Fertilization in kg ha-1 the first five growing years. The numbers in brackets show the content of available nutrients in 0-20 cm depth prior to fertilization. Crop 2002 2003 2004 2005 Nutrient N P K N P K N P K N P K Elephant grass 320 420 180 84 16 40 84 16 40 85 16 40 Reed canary grass 320 420 180 84 16 40 84 16 40 85 16 40 (18) (560) (290) (14) (528) (370) Sorrel (7) (540) (270)

Crop 2006 Nutrient N P K Elephant grass 85 8 46 Reed canary grass 85 8 46 Sorrel 65 6 35

Growth parameters have been measured since establishment, and combustion characteristics measurements started after two years growth.

2 Materials and methods The methods for evaluation of the energy crops are shown in table 3.

Table 3. Methods for evaluation of energy crops Characteristics Methods Gross caloric value ISO 1928-76 (adiabatic bomb calorimeter) Ash content 550°C – 20 hours Water content 105° - constant weight Volatiles 1-50 K/min – 110ºC – 600ºC (TGA) Mortality, health, weeds Visual

The samples for yield and combustion characteristics have been collected this way: • Reed canary grass. Every year a fixed area of 12 m² is harvested green in November in order to determine the winter loss. In April or March depending on the climate six blocks of 12 m² are harvested dry. This is the main harvest and it is carried out with a motor

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scythe. Spring harvesting is preferred as it gives a better fuel quality, i.e. lower water content and reduced content of alkali and chlorine [3] • Elephant grass. All plants are harvested dry every year in April-May with pruning shears. • Sorrel. The first harvest will be in the summer of 2007 since there is nothing to harvest the first year. The water content by summer harvest is expected to be 15-20 % [1].

3 Results and discussion 3.1 Mortality, health, weeds The growing rate of elephant grass is shown in table 4. The table shows clearly that elephant grass, Miscanthus x giganteus had a high mortality the first winter, which agrees with trials in Sweden and Denmark [4]. The plants resist frost better as the rhizomes grow bigger even in our climate. In addition all plants survived a removal into one row in the autumn of 2004. Weeding was necessary the first three years, but as the plants now are nearly closing the row, weeding has been omitted in 2005 and 2006. Elephant grass has so far been a healthy crop, and it reaches heights up to 346 cm, measured in October 2006.

Table 4. Survival of elephant grass since establishment. Year 2002 2003 2004 2005 2006 Number of living plants 628 85 72 72 72 Survival rate, % 13.5 85 100 100

Reed canary grass was established by broadcasting of the seeds, and weeds have been a minor problem. Only very few thistles and mugworts have manually removed each year.

Sorrel was established in single rows 30 cm apart. This has been an advantage for necessary manual weeding and loosening of the soil as described by [1]. The crop has been healthy so far, but it will be interesting to follow the winter survival and growth the next years.

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3.2 Yield and combustion characteristics Reed canary grass, Phalaris arundinacea 'Bamse' has been extensively tested with springharvesting. The results are shown in table 5. The yield reached its maximum the second year with 8 tonnes dry matter per ha. The level and the development of the yield are very similar to trials in Southern Sweden and Denmark as referred in [5, 6]. The winter loss the first year agrees with the same trials, but the decreasing loss second and third year originates from the fact that yield develops differently in different harvesting systems [5]. The variation of the yield between the different 6 blocks is decreasing over the years. Coefficient of variation was respectively 12.7, 4.4 and 3.7. This indicates that the large variation the first year was due to differences in plant establishment, which the plants themselves now have compensated for.

Table 5. Yield and combustion characteristics for reed canary grass established 2002. Harvest Harvest Harvest 30 March 2004 19 April 2005 24 April 2006 -1 -1 Yield, kgDM ha a 6650 8000 6540 Water content, % 11.9 8.6 25.4 Winter loss of dry matter, % 15 4.7 0.0 Net calorific value MJ/kgDM 16.6 16.46 16.88 Ash, determined by kiln, % DM 2.6 2.3 3.0 Volatiles, %DM 72.3 73.1 73.5

The accumulated yield in reed canary grass so far is 21190 kg dry matter per ha. In comparison willow in the same field and period yielded accumulated between 26100 and 50850 kg dry matter depending on the harvesting cycle and the clone [7]. Still reed canary grass has an advantage in cheap establishment from seeds, and use of traditional agricultural machinery. Elephant grass yielded only around four tonnes dry matter per year in 2004 and 2005. It was not measured in 2006, but it will be interesting to see the development the next years.

Water content in straw bales should be lower 20 % for storage [8, 9]. This was achieved in 2004 and 2005, but in 2006 the reed canary grass field was covered with snow until 19 April. We then had to accept high water content as we wanted to avoid damage of the new growth. The first stable dry period after the snow was gone started 3 May, where the mean temperatures were 12-17 ºC. In 2005 the optimal period for harvesting lasted 17 days with temperature between 4 and 10 ºC. In elephant grass the optimal period is even longer as the straw is standing upright without contact with the soil. According to measurements in 2005, two days with less than 1 mm rainfall makes straw with less than 20 % water [10]. The water content varied between 11 and 48 % from 1 April-9 June 2005.

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The combustions characteristics for reed canary grass in table 5 are quite even from year to year. Even a test of elephant grass from 2005 shows similar values, net calorific value 16.67

MJ/kgDM and ashes 2.2 %. The relatively low ash content in reed canary grass agrees with [3] for sandy soil. The ashes will only cause few problems as ash fusion temperature for spring harvested reed canary grass is much higher compared to wood and summer harvested grass [3].

4 Conclusions • In order to secure the survival of elephant grass, Miscanthus x giganteus the first winter after establishment, covering should be considered. Our experience indicates that the size of rhizomes is very important. • There are normally only a few days suitable for harvesting reed canary grass in spring, which makes it a risky crop if water content below 20 % is required. On the other hand it is an easy crop to grow, and is well suited for combustion. • Elephant grass and reed canary grass should be harvested in the spring, and thus needs storage until the next heating season. Sorrel by its July/August harvest of dry material represents a promising novelty. • It is possible to harvest all three lignocellulosic energy crops at relatively low water contents. • The yield of dry matter per ha per year in the tested grasses is relatively low compared to willow under same conditions. In reed canary grass the yield seems to decrease from the second year on.

References [1] Ust’ak S.; Ust’akova M. (2004): Potential for agricultural biomass to produce bioenergy in the Czech Republic. OECD Workshop on Biomass and Agriculture: Sustainability, Markets and Policies, 10-13 June 2003, Vienna, Austria; OECD Publishing: p. 229-239 [2] Norwegian Meteorological Institute, www.met.no [3] Burvall J. (1997): Influence of harvest time and soil type on fuel quality in reed canary grass (phalaris arundinacae L.). Biomass and bioenergy 12 (3): p. 149-154 [4] Clifton-Brown J.C.; Lewandowski, I.; Andersson, B.; Basch, G; Christiand, D.G.; Kjeldsen, J.B.; Jørgensen, U.; Mortensen, J.V.; Riche, A.B.; Schwarz, K-U.: Tayebi,

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K.; Teixeira, F. (2001): Performance of 15 Miscanthus Genotypes at five sites in Europe. Agronomy Journal 93: p. 1013-1019. [5] Landstrom, S.; Lomakka, L.; Andersson, S. (1996): Harvest in spring improves yield and quality of reed canary grass as a bioenergy crop. Biomass and Bioenergy 11 (4): p. 333-341. [6] Mortensen, J.; Jørgensen, U. (2000): Reed canary grass as an energy crop. In “Do energy crops have a future in Denmark?” DJF rapport markbrug 29: p. 30-41 [7] Kunze, M.; Nielsen, H.K.; Ahlhaus, M. (2006): Yield of woody biomass from southern Norway and their suitability for combustion and gasification purposes depending on the harvest frequency. 2nd International Baltic Bioenergy Conference, November 2- 4, 2006, Stralsund, Germany. [8] Wieneke, F. (1972): Verfahrenstechnik der Halmfutterproduktion, Göttingen: p. 8 [9] Gylling, M. (2001): Energiafgrødeprogrammet: Hovedrapport. Statens Jordbrugs- og Fiskeriøkonomiske Institut (now Institute of Food and Resource Economics) report 131: p. 65 [10] Kunze, M. (2005): Untersuchung der Eigenschaften verschiedener Energiepflanzen. Bericht über das „Scientific project“. Hochschule Offe

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Optimized Cropping Systems for the Agricultural Production of Energy Crops in Mecklenburg-Vorpommern

Jana Peters State Research Institute for Agriculture and Fishery of Mecklenburg-Vorpommern, Gülzow, Germany

The project is promoted by the BMVEL and the Agency of Renewable Resources (FNR).

Introduction The rapid increase of biological gas facilities led to an expansion of the silo maize area in 2006. Know there are in Mecklenburg Vorpommern approximately 10,000 hectares for Biogas production. In order to ensure the expected further development of sustainable biomass energy production, larger diversity at energy crops should be used. Consequently special crop rotations have to be established. Therefore different suitability agricultural crops are investigated regarding their productive capacity for typical local conditions in Mecklenburg Vorpommern. This project is a part of the project packages „development and comparison of optimized cultivation systems for the agricultural production of energy crops under the different local conditions of Germany “. The main objective of this project is an optimization of the net power production adapted to the national conditions. The quality necessary for Biogas and economic aspects should be taken into consideration.

Material and methods Five standard crop rotation systems for energy production are investigated in six selected typical agrarian regions of Germany for three years. Additional to these five standard crop rotations, there are three local crop rotations for energy production. The crop rotations consist not only of pure energy crops but also of cash crops. The bold marked crops in table 1 are used for biogas production.

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Table 1: Representation of the energy crop rotations CR 2005 2006 2007 2008 1 summer barley (CC) maize winter triticale winter wheat oil radish (SZF) 2 sudan grass maize winter triticale winter wheat green cut rye (WZF) 3 maize sudan grass winter triticale winter wheat green cut rye (WZF) 4 summer barley (CC) clover clover winter wheat underseed clover 5 oats sort mixture (CC) winter triticale winter rape winter wheat Crop Rotation Mecklenburg-Vorpommern 6 maize barley grass winter rape winter wheat 7 maize field grass field grass winter wheat green cut rye (WZF) 8 mix of summer rye /summer winter rape winter wheat winter wheat triticale (CC) CC-Complete Crop, SCC-Summer Catch Crop, WCC-Winter Catch Crop

Beside the net energy yield per hectare it should be possible to investigate following questions: • effects of the individual crops on the hole crop rotation • Influence of crops on humus, nutrient and water content of the soil • Determination of crop health effects in the crop rotation system • Classification of “new” crops into the agro technical system • effects on natural flora and fauna • economical and ecological evaluation of different cultivation intensities • comparative evaluation of food, feed and Non food production Extensive databases are necessary to evaluate these issues. In order to guarantee unique evaluation system the energy crops have to be harvested at the same dry matter content.

Results

Up to now we have results from the first experimentally year. The biogas yield in figure 1 where calculated by means of a formula by Baserga [1].

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Figure 1: Representation of the Biogas yields of 2005

CR Kinds of fruit [m³/ha] Biogasyields 1 summer barley, oil radish 12000 10000 2 sudan grass

11305 3 maize 10995 8000 10947 6000 4 summer barley with underseed 4000 5 oats 4941 4556

2000 4039 3799 3786 6 maize 0 7 maize 12345678 8 mix of summer rye/summer triticale Crop Rotation

Usually the sudan grass has nearly as high yields as maize. Surprisingly in our experiment in Gülzow the yield was much lower. Sub optimized cultivation conditions could be reasons for this low yield. Thus bad weather conditions negatively influenced the yields in spring 2005. Furthermore up to now there is only a limited practical knowledge of cultivation of sudan grass in this region. To early seed and to early harvest dates could be responsible for the low dry matter yields. Although the fresh mass yields where high, the dry matter content was low (see figure 2). Therefore, regular monitoring should be ensured in order to get the optimal harvest date (DM 30%). The cereals did not differ substantially in biogas yield, however the yield where much lower than the measured for maize.

Figure 2: Representation of the yields of 2005

Yields [dt/ha] CR Kinds of fruit 800 1 summer barley, oil radish 701

600 685

677 2 sudan grass 602 601 400 3 maize 213 207 206 4 summer barley with underseed

200 294 116 270 104 102 96 251 89 5 oats 0 6 maize 12345678 7 maize fresh mass Crop Rotation dry matter 8 mix of summer rye/summer triticale

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The biogas yield is affected strongly by the composition of the material used. The digestibleness of the silage plays an important role for the optimal utilization of the biomass in a biogas plant. For further investigations it is necessary to characterize the crop material and find out the optimal composition of the crop material for biogas production.

References [1] Schattauer, A.; Weiland, P.: Grundlagen der anaeroben Fermentation; Handreichung Biogasgewinnung und –Nutzung. Fachagentur Nachwachsende Rohstoffe e.V. Gülzow, pg. 25-35, 2005

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Biomass for energy from rewetted peatlands

Dr. Wendelin Wichtmann Institute for Sustainable Development of Landscapes, Greifswald, Germany

Abstract In Germany the demand for biomass for energy purpuses is increasing. The shortage of biomass can already be observed in hardening of prices. On arable lands conventional agri- culture for comestibles competes with cultivation of industrial and energetical raw materials. Coevally the requirement for fen grasslands is declining. This implies a great chance for new concepts of land use on fen peatlands, that are no longer needed for grassland production. The utilisation of fens as grasslands is generally accompanied by heavy environmental im- pacts and the loss of species diversity. Here an alternative concept for fen-peatland use is proposed which involves the reestablishment of wet conditions. The naturally developing, high productive reed stands can be used as an energy source in direct combustion or for the production of liquid ‘sun fuels’. The plantation of habitat-adapted plant species after rewetting could be a feasible alternative to spontaneous vegetation development. This practice helds economical promises. In Northern Germany alone, about 200,000 hectares of lowlands could be rewetted for biomass production. The harvest from these areas could feed 20 power plants of 20 MW capacity each.

1 Introduction In future the biomass demand of co-generation power stations will increase. Besides forests rewetted peatlands may play an important role for their supply because of their very high productivity. In Northern Germany we find more than 800,000 hectares of fen peatlands which are to some extent still used as high-intensity grasslands. Heavy draining leads to a continuing decline of habitat quality and negatively affects adjoining water bodies, the ground water and the atmosphere. This kind of management contradicts the demands of sustainable land use [1,2] and the principles of the Good Agricultural Practice (§ 17 federal law of soil conservation). It also causes costs to the national economy since the achievement of environmental policy goals requires substantial funds. Since the revision of the renewables legislation in Germany (EEG, 2004) the energetic use of biomass became more attractive. This can already be noticed on the biomass markets. Waste wood and other combustable garbages that had been burned for charge by the combustion plants nearly disappeared on the market. Prices for biomass are rising. Demand for biomass as renewable energy source increases last but not least as raw material for co-generation

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power stations and private consumption for domestic fuels (ovens and fire places). Arable lands for the cultivation of renewable energy sources competes with other renewables for gasoline production like rape, corn and cereals. Big industrial consumers for cereals built plants for pruduction of biodiesel and bio ethanol the last years, several biomass to liquid (BTL) industries will be constructed in northern Germany in future. New raw material potentials must be developed for the bio energy demand of tomorrow. Biomass from rewetted peatlands can make a contribution to close the gaps in supply.

2 Rewetted peatlands as sources for biomass 2.1 Land use trends on peatlands With the decrease of cattle breeding in eastern Germany the utilisation pressure on grass- lands on fen peatlands decreased. In Mecklenburg-Vorpommern for instance 80 thousand hectares of peatlands are no longer needed by agriculture. They are still managed with low intensity to assert EC-money under minimal efforts. To meet EC-Cross Compliance (CC) conditions it is necessary to mulch the grassland at least every second year. The use of the biomass within agricultural production is problematc or unpossiple. Environmental aspects are the main reasons for actual restoration measures of the governments of some federal states because the continuation of actual grassland use connected with drainage of the peatlands brings huge amounts of CO2 into the atmosphere. Rewetting firstly aims to stop this process of peat decomposition advantaged by heavy drainage activities. On the other hand, nature conservation plays a role within the restoration programmes of the federal states. Normally these restored peatlands are not managed and are open for free succession. New sites are developing with totally new conditions that need the imple- mentation of new land use concepts. Due to the decrease in land-use pressure and the problems of conventional fen utilisation, concepts for environmentally compatible land use have received growing attention. Several research projects have tested sustainable land-use alternatives which aim to avoid or minimise the negative environmental impacts of degraded fen peatlands. The plant biomass that develops after rewetting is of different qualities and allows for differentiated uses, mostly outside food production.

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2.2. Site adapted land use Future land use on fen peatlands, that meets the goals of international conventions (eg biodiversity convention or climate convention), must orientate at reduction of emmissions and on restoration of fuctions and regulating mechanisms of peatlands. These goals are achievable by rewetting of the peat soils with water tables at soil surface the whole year. By that peat forming conditions can be achieved. After rewetting of the former heavily drained eutrophic – polytrophic peatlands these have the potential to accomodate high productive Common Reed (Phragmites australis) [4] and Reed Canary Grass (Phalaris arundinacea) stands. These species develop under very wet and ponded conditions naturally. It is also possible to cultivate Common Reed to accelerate the process. Also the cultivation and harvest of cattail (Typha latifolia) [5] has been tested, as well as the afforestation of fens with black alder (Alnus glutinosa) [6]. It is reasonable and necessary to harvest these high productive ecosystems, to avoid nutrient releases and to develop biodiversity. Until now the use of biomass from rewetted peatlands only had been investigated under the perspective of industrial utilisation [7,8,9]. Under polytrophic conditions, rewetted fens often produce more than 15 t · ha−1 dry matter per annum, dependent on plant species, trophy and hydraulic conditions (table 1). Mowing is an effective method of harvesting the biomass evenly. The quality of the produce depends on the site conditions and the resulting plant species composition as well as the time of harvest. Conservation rules (protection of grassland birds, fostering of protected plant species) also have to be considered in many cases.

2.3 Agricultural aspects of biomass production on rewetted fen peatlands For agriculture, site adapted and sustainable land use on rewetted peatlands is an innovative and cost effective chance. Since the implementation of acreage independent payments by the EC in 2005 that made subsidies independent on production, farmers do not want to give up land use and accordingly do not feel up to allocate peatlands for restoration measures. Harvesting the biomass from rewetted sites allows for sustaining their typical functions and has the following advantages: • Assessment of alternatives for site-adapted land use, adoption of new land-use concepts with minimal damage to the environment

• Mitigation of CO2-gas emissions • Fostering of peat-forming plant species, restoration of the sink function, e.g. for carbon and nitrate • Restoration of habitats for mire key-species, improvement of the habitat function • Production of raw materials for energetic and industrial uses,

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• Nutrient removal from ground- and surface waters • Revitalisation of traditional land uses combined with new ways of processing The higher the usable harvest and the lower the peat depletion caused by the land use, the more ‘site-adapted’ is the production practice

2.4. Biomass from succession plant-communities With rewetting of a peatland a considerable dynamics of vegetation development and che- mical conversion commences. Depending on water regime, trophy level, seed potential and other factors, the development of the vegetation first leads to reed beds of Reed Canary Grass (Phalaris arundinacea), Sweet Reedgrass (Glyceria maxima), Common Reed, or Cattail (Thypha spec.), more rarely to sedge (Carex spec.) reed-beds, but also to Grey Willow (Salix cinerea) shrubbery. Near-natural reed beds are typical insect and bird habitats of Northern Germany. Many of these animal species are endangered due to the Europe- wide decline of wet reed beds. These plant communities develop spontaneously after rewetting and can be harvested according to the intended use of the biomass (fig. 2). An overview of such succession communities gives table 1 which makes it clear that not all of the plant species described are of economical interest because the area yield of some is too low. Table 1: Productivity of reeds and wetlands [10] Species Productivity t · ha−1 · a−1 Common Reed (Phragmites australis) 3.6 .. 43.5 Cattail (Typha latifolia) 4.8 .. 22.1 Reed Canary Grass (Phalaris 3.5 .. 22.5 arundinacea) Sweet Reedgrass (Glyceria maxima) 4.0 .. 14.9 Great Pond-sedge (Carex riparia) 3.3 .. 12.0 for comparison: Fallow wet 6.4 .. 7.4 grassland 8.8 .. 10.4 High-intensity grassland

The selective cultivation of site-adapted plant species like common Reed can provide higher harvest security than the utilisation of succession communities.

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3. Properties of biomass from rewetted peatlands (brp) 3.1. Critical contents Also quality and amount of biomass from rewetted peatlands (brp) is dependent on site con- ditions, espacially from hydrology and trophic situation. Also the energy recovery options correspond with this. In terms of energetical utilisation of rpm there are some lacks of know- ledge. There have already been many studies about combustion siutability conducted in cereals and Miscanthus sinensis. The energetic utilisation of grasses and cereals is normally connected wih some problems. Critical contens of sulfur and chlorides may induce corrosion at technical components of the co-generation power station that are affected by exhaust fumes. Most grasses have much higher content of ashes than wood. Also the ash melting temperature often is lower than for fire wood and may cause technical problems like slag- ging. Overtaking results from research on Miscanthus sinensis or cereals therefore is proble- matic because these normally are cultivated on mineral soils. Furthermore these grasses are manured with mineral fertilisers or organic liquid manure that comprise potassium, sodium, chlorides and sulfur. This will not be necessary on rewetted organic soils. They have normally much lower natural contents of these substances an firtilisation is not necessary. As espected, these attributes are reflected in brp quality.

3.2 Reed canary grass (Phalaris arundinacea) Dominant stands of reed canary grass already developed by natural succession in large areas that have been rewetted within restoration projects in Northern Germany, where not enough water was available for total rewetting (humid to wet conditions). In Mecklenburg- Vorpommern a total aea of 20 to 40 thousand hectares is assumed. Reed Canary Grass may also be established after ploughing by sowing. Different from the normal practice in agriculture harvest can be done in winter. By such late harvest dates the combustion properties are improved considerably (contents of S, Cl, K are declining). Yields between 3,0 to 15 tons per year and hectare are possible. Peat decomposition is very low or stopped by the prevailing hydraulic conditions. From the view of nature conservation Reed Canary Grass reeds are not very interesting. On this still research activities are necessary. For reed canary grass, cultivated for combustion some results are available for different harvest dates [11]. The influence of the date of harvest on the combustion charachteristics of Reed Canary Grass is also discribed by other authors [12].

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Table 2: Influence of harvest date of reed canary grass of different Swedish sites [12]. Parameter Jul./Oct. March/May net calor. temp. (MJ/kg TM) 17,9 (0,91) 17,6 (0,85) Carbon % 46 (1,2) 46 (1,53) Ash-deformation °C 1074 (61) 1404 (183)

Reed Canary grass had been harvested the 23rd of October and the 18th of March. The second date of harvesting the chlorine content was only about 10% (Cl 23.10.: 0,485% of dry matter, Cl 18.3.: 0,042 %) of the contents of the first date. Other combustion tests with Reed Canry Grass material show that this biomass had high ash and silica contens that made problems in the combustion chamber [13]. Incineration of this material was connected with higher NOx-emissions than firing of wood.

3.3 Common Reed (Phragmites australis) Natural reed stands form linear structures in landscapes at banks of lakes and rivers and also on the watersides of lagoons. On the other hand large areas they are found in more or less virgin fen peatlands. Also after rewetting of formerly high intensively used peatlands they develop by succession or they can be established by cultivation [14, 15]. Traditionally harvest for roofing material takes place in winter. Yields of about 3,5 – 43,5 t/a and hectare are discribed in literature (table 1) for Central Europe, realistic expectations are assumed at 8-15 t/a [10]. The sites are generally eutrophic to polytrophic and are flooded nearly the whole year. Reed beds are potentially peat forming, Reed itself is very efective in peatforming with very positive influences on the environment, shown by deep Phragmites- peat profiles in fens. Nature conservation values are medium to high (eg for some specialists species). Table 3 compares the analysis results for Common Reed [17] and Reed Canary Gras [13] in comparison to spruce wood including bark [16]. The values for carbon content are com- parable.(Tab. 2). Ash contents of the two grasses are about 10 times higher than those of wood. Nitrogen and Sulfur values are five to 10 times higher and Chlorine contents 10 to 40 times higher than the values for wood. The high values for these substances may be based on the above mentioned fact, that Reed Canary Grass had been firtilised and cultivated on mineral soils and the Common Reed samples came from the banks of the “Neusiedler See” in Austria, which has nearly brackish salt conditions.

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Table 3: Elementary analysis of dry matter of different biomasses. Values in weight % Common Reed Reed Canary Grass Wood from spruce [16] Carbon 46 - 47 45,4 49,8 Sulfur 0,04 - 0,05 0,1 0,015 nitrogen 0,24 - 0,30 0,62 0,13 Chlorine 0,2 0,05 0,005 Ash 5,12 8,0 0,6

The ash melting of Common Reed from the “Neusiedler See” about 1420 °C is higher than the value for wood and Reed Canary Grass. This leads to the assumtion that there are no problems in contrast to other grasses and cereals in combustion[17]. As well the melting behavior and the slagging factor Rs figure on that with commonly used firing techniques no slagging will occur [18]. The lower heating value for Common Reed is about 17,5 MJ/kg [16] and for Reed Canary Grass about 16,9 MJ/kg [13]. These values are similar to other grass biomasses and abot 2 MJ/kg lower than the value for wood [17]. Firing Reed from the “Neusiedler See” under optimal conditions caused lower emissions of CO and unburned hydrocarbons below 50 mg/Nm3. Besides no nameable emissions of dioxines and Furanes are anticipated [18]. The combustion of Reed from the Neusiedler Sees caused extended

SO2-emissions of about 20 - 50 mg/Nm³. By using tissue filter systems and addition of lime into the smoke gas stream SO2- und HCl-emissions can be neutralised [18].

4 Biomass for energetic and industrial uses If the harvested biomass is intended for energy production or as a raw material for the bio- mass to liquid process (BTL) the harvesting machines employed may be less sophisticated and expensive than in the production of quality reed [15]. The transport, for instance, can proceed in big bales. Table 2 shows the revenues farmers can gain from low-quality bio- mass. The individual cost figures were derived from data in the literature [19]. The labour costs were totalled with the fixed and variable costs. Energy production with combined gene- ration of heat and electricity is already cost-efficient at biomass prices as high as 46 €/t [20]. This means that a farmer in the scenario in the central column of Table 5 is operating at the break-even point. A farmer in the high-productivity scenario (right column) with a harvest of 20 t · ha−1 dry matter could achieve a substantial profit. Choren Industries from Freiberg in Saxonia and the Shell Corporation are currently planning the construction of a biomass-to- liquid (BTL) plant in Lubmin near Greifswald. It will require unspecific biomass with high car- bon and low water contents (less than 35 per cent water). These requirements are met easy- ly by both types of brp, Reed Canary Grass and Common Reed as well. With that they are applicable for the BTL process. Absolute dry biomass is currently (personal communication Waitz,Choren AG 2005) priced at 50 to 80 €/t dry matter. The subsidy-dependent, low-pro-

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ductive use of grasslands yields a revenue of 116 €/ha, based on the usual prices for litter. Even at a low price of 40 €/t, the user of a productive reed bed would already make some profit (Table 5, right column). Assuming that the price of energy will rise in the future, the profit will be even higher. At biomass prices of 60 €/t, even less productive stands (Reed Canary Grass: 8 t · ha−1) would be cost-efficient. It is conceivable that such stands could have a significantly higher productivity which would result in lower costs and increase the cost-effectiveness of the practices introduced above. The calculations presented here incorporate the EC-land premium for grassland that will achieve about 300 €/ha/a in 2013. Unfortunately until now this is currently not paid for reed beds in Mecklenburg-Vorpommern.

Table 4: Revenues from sustainable biomass cultivation on fen peatlands [8] Reed Canary Reed Reed Grass, sedges, Canary Glyceria Grass Unit Time of harvest Summer Winter Winter Yield t DM 5 8 20 Big bales 250 kg 20 32 80 Costs (fixed and variable): Harvest [19] € 210 250 450 Transport, storage € 16 25 63 Trading €/ha 63 100 250 Sum € 288 375 763 Subsidies € -204 − − Revenue 40 €/t €/ha -88 (116) -55 37 80 €/t 112 265 837

The costs per tonne are lower than common biomass prices, if EC-payments can be achieved. Without this premium it will be necessary to optimize the production process be- fore this practice will becomes widely accepted.

5 Area potential in northern Germany An assessment for Northern Germany with a total area of 830 Thousand hectares of peat- lands showed, that potentially a quarter of this area could be managed for brp-biomass pro- duction [8, 21]. If yields about 10 tonnes are assumed per hectare and year, about 20 Million tonnes dry biomass for combustion in energy plant would be available. This corresponds with the demand of 20 biomass-combustion plants with 20 MW-capacity each [dates deduced after 22]. This assessment needs acurate research to make relaiable statements.

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6 Copnclusions and outlook The amount of the potentially available area shows that biomass from rewetted fen peatlands could contribute significantly to the generation of heat, electricity and liquid fuels (BTL). Given a continuing rise in the prices of fossil fuels, the energetic utilisation of biomass is becoming ever more attractive. Parameters for assessment of the combustion charach- teristics are very promising. The cultivation and processing practices introduced will be the more relevant for the individual farm the more generously it is endowed with degraded fen sites. An expansion in the processing of biomass from rewetted fen peatlands could secure jobs for the long term or, as the case may be, help to make better use of free labour capacities. It is proposed that all fen peatlands that are currently used as sown grassland should be rewetted wherever the hydrological conditions permit it. Because of shortages in water avail- ability it is assumed that the water will only suffice for less than half of the peatlands. The rest should be managed as grasslands for agricultural needs. The rewetting of peatlands should not touch the status of the sites as farmland. What determines their status is exclusively whether they are being used or not. The current rise in the demand for energy biomass will accelerate their large-scale implementation. An examples from Northwestern Poland (Rozwarowo) shows, that reedbed management ist Cross Compliance compatible which makes regular EC –payments possible.

References [1] Succow, M. & H. Joosten (ed.) 2001: Landschaftsökologische Moorkunde. Schweitzer- bart´sche Verlagsbuchhandlung [2] Joosten, H. & D. Clarke 2002. Wise use of mires and peatlands – background and prin- ciples including a framework for decision-making. Finland: Saarijärven Offset Oy, 303 pp. [3] Roth, S., D. Koppisch, W. Wichtmann & J. Zeitz (2001): Moorschonende Grünlandnutzung” - Erste Erfahrungen auf nordostdeutschen Niedermooren. In M. Succow & H. Joosten (ed.) Landschaftsökologische Moorkunde. Schweitzerbart´sche Verlagsbuchhandlung, 472– 480. [4] Wichtmann, W. & M. Succow (2001): Nachwachsende Rohstoffe. In R. Kratz & J. Pfadenhauer (Hrsg.): Ökosystemmanagement für Niedermoore - Strategien und Verfahren zur Renaturierung. Eugen Ulmer Verlag, Stuttgart. S. 177 – 184 [5] Wild, U., Kamp, t., Lenz, A., Heinz, S. & J. Pfadenhauer (2001): Cultivation of Typha spp. in constructed wetlands for peatland restoration. Ecological Engineering 17: 49 - 54.

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[6] Barthelmes, A., Joosten, H., Kaffke, A., Koska, I., Schäfer, A., Schröder, J. & M. Succow 2005. Erlenaufforstung auf wiedervernässten Niedermooren. Greifswald: Institute for Sustainable Development of Landscapes of the Earth, 68 pp. [7] Wichtmann, W. Knapp, M. & H. Joosten (2000): Verwertung der Biomasse aus der Offenhaltung von Niedermooren. Z. f. Kulturtechnik und Landentwicklung 41: 32 – 36. [8] Wichtmann, W. & A. Schäfer (2005): Energiegewinnung von ertragsschwachen Acker- standorten und Niedermooren – standortgerechte Bewirtschaftung zur Offenhaltung der Landschaft in Nordostdeutschland. Natur und Landschaft 9/10: 421-425 [9] Succow, M. & H. Joosten (2001): Landschaftsökologische Moorkunde. Kap. 8 und Kap. 9. Schweitzerbart´sche Verlagsbuchhandlung, 622 S. [10] Timmermann, T. 2003. Nutzungsmöglichkeiten der Röhrichte und Riede nährstoffreicher Moore Mecklenburg-Vorpommerns. Greifswalder Geographische Arbeiten 31: 31 - 42. [11] Mortensen, J. (1998): Yield and chemical composition of reed canary grass populations in autum and spring. Sustainable agriculture for food, energy and industry. James & James ltd. pp 951 – 954 [12] Burvall, J. & B. Hedman (1998): Perennial rhizomatous grass The delayed harvest system improves fuel charachteristics for reed canary grass. Sustainable agriculture for food, energy and industry. James & James Ltd. 916 -918 [13] Kastberg, S. & J. Burvall (1998): Perennial rhizomatous grass – Reed canary grass as an upgraded bio-fuel: experiences from combustion tests in Sweden. Sustainable agriculture for food, energy and industry. James & James Ltd. 932 - 937 [14] Timmermann, T. (1999): Anbau von Schilf (Phragmites australis) als ein Weg zur Sanierung von Niedermooren - Eine Fallstudie zu Etablierungsmethoden, Vegetationsentwicklung und Konsequenzen für die Praxis. Archiv für Naturschutz und Landschaftsforschung 38, 2-4: 111-143 [15] Wichtmann (1999): Schilfanbau als Alternative zur Nutzungsauflassung von Nieder- mooren. Archiv für Naturschutz und Landschaftsforschung 38 (2-4): 97-110 [16] Hartmann, H. Thuneke, K., Höldrich, A. & P. Rossmann (2003): Handbuch Bioenergie- Kleinanlagen. FNR Gülzow. Tangram documents, Bentwisch. 184 S. [17] Eder, G., Haslinger, W. & M. Wörgetter (2004): Gutachten energetische Nutzung von Schilfpellets. Im Auftrag des Amtes der Burgenländischen Landesregierung, Abt.9, Wasser- und Abfallwirtschaft, 53 S [18] Hofbauer, H., Linsmeyer, T. & Ch. Steurer (2001): Machbarkeitsstudie Schilfverwertungs- anlage. Enbericht - Kurzfassung, 29.11.2001. Amt der Burgenländischen Landesregierung. Abt. 9, Wasser- und Abfallwirtschaft. Landeswasserbaubezirksamt Schützen/Geb.

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[19] Reinhold, G. 2001. Betriebswirtschaftliche Bewertung der Bereitstellung von Stroh und E- nergiegetreide. - In: Gülzower Fachgespräche: Energetische Nutzung von Stroh, Ganz- pflanzengetreide und weiterer halmgutartiger Biomasse. Gülzow: Fachagentur für Nach- wachsende Rohstoffe , pp. 50 - 61. [20] Heinrich, P. & B. Jahraus 2000. Stromerzeugung aus Biomasse: Überblick über die tech- nischen Verfahren und deren Wirtschaftlichkeit. Gülzower Fachgespräche: Energetische Nutzung von Biomasse durch Kraft-Wärme-Kopplung. Tangram, Rostock pp. 25-39. [21] Wichtmann, W. (2003): Verwertung von Biomasse von Niederungsstandorten. Greifs- walder Geographische Arbeiten 31: S. 43 – 54. [22] Thrän, D. & M. Kaltschmitt (2001): Stroh als biogener Festbrennstoff in Europa. Gülzower Fachgespräche, Bd. 17. Tangram Documents Rostock: 85-102

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BIOMASS CONDITIONING FOR SOLID BIOFUEL COMPOSITIONS

Prof. Dr. ing. Eriks Kronbergs, assoc. prof. Dr. Ing. Aivars Kakitis, assist. Msc. ing. Mareks Smits, assist. Msc. ing. Imants Nulle* Institute of Mechanics, Faculty of Engineering, Latvia University of Agriculture, Jelgava, Latvia

Summary

The article presents investigation of straw, common reed and peat biomass conditioning for solid biofuel compositions production. Biomass conditioning mainly includes stalk material flattening, cutting, separation, dosage, mixing and compaction operations (making briquettes or pellets). It is stated double advantage of using herbaceous biomass and peat compositions for briquetting, because density of briquettes 1.0 g cm-3 is obtained and the formation of chlorides during combustion process is avoided. Density 1.0 g cm-3 has been obtained in compaction of straw stalk material particle compositions with peat, if peat proportion exceeds 35%. Durability 0.6 MPa of reed briquettes can be obtained with particle size less then 0.5 mm, ultimate shear stress 0.6 MPa for the straw briquettes can be obtained by adding ~60% of peat.

Introduction As the fossil fuel resources are decreasing, in future we will have to rely on renewable energy sources. The most significant part (74%) of renewable energy sources has been planned for biomass energy in European Union. The main resources for solid biofuel in rural area of Latvia are residues of cereal crops, peat and emergent vegetation in lakes as common reeds (Phragmites australis). Straw more than 340 000 t annually can be used for heat production. Besides that more than 230 million tons of peat are available for biofuel production. The 2003 reform of the EU Common agricultural policy means that income support for farmers is no linked to the crops produced. As a result, farmers can respond freely to increasing demand for energy crops. This reform also introduced a special “energy crop payment” under which a premium of €45 per hectare [1] is available for the production of energy crops. The reform stimulates farmers to grow more energy crops, including short rotation coppice and other perennial crops. Peat can be used as additive for manufacturing of solid biofuel, because it improves density, durability of stalk material briquettes (pellets) and avoid corrosion of boilers. The burning performance of stalk material biomass fuel if we use peat additive is improved also. If only wood chips or herbaceous biomass are burned, the sulphur content is low and chlorides are formed [2]. The chlorides then tend to condense on heat transfer surfaces of the steam boiler, slowing down the heat transfer and causing

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the risk of high temperature corrosion. If the sulphur content of the fuel is increased, e.g. by blending peat with chips or herbaceous biomass, sulphates are formed instead of chlorides and high temperature corrosion is avoided. For these reason herbaceous biomass compositions with peat for solid biofuel production is recommended.

Naturally herbaceous biomass is a material of low density (0.02–0.06 g cm-3) and is not favourable for transportation over long distances. Those biomass properties cause necessity of appropriate mechanization equipment for biomass conditioning for solid biofuel production in shape of pellets or briquettes. Dry vegetation materials contain stalks as the main part of biomass. Therefore biomass conditioning mainly includes stalk material flattening, cutting separation, dosage, mixing (making compositions) and compaction (making briquettes or pellets). The article presents investigation of straw and common reed biomass mechanical and cutting properties which determinate shredder design for size reduction before compacting. Also presented screw feeder throughput investigation for peat dosage, briquetting energy requirement for biomass compositions briquettes and durability tests of briquettes.

Materials and methods Material flattening and cutting (shredding) are necessary conditioning operations before briquetting. The energy crop stalks (stems) are more useful with delayed harvesting for solid biofuel production [3], than leaf blades, therefore mainly stalk material cutting properties have to be investigated for shredder Fig. 1. Reed stalk design. For Latvia situation experimental investigation of flattening common reed stalk conditioning properties as F flattening and cutting can characterize maximum of 4 2 energy consumption in these operations for all 3 group of mentioned stalk materials because reeds 1 have higher tensile strength (~200 N mm-2) and accordingly another strength parameters. b) Cutting and flattening of different length reed specimens with moisture content of 10% had been investigated by means of Zwick material testing a) machine TC-FR2.5TN.D09. Displacement, stress Fig.2. Flattened reed cutting device and energy data were collected on the computer.

Specific cutting energy per area unit Escq for stalk biomass had been calculated using equation:

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E E = c , (1) scq A

-2 where Escq – specific cutting energy per area unit, J m ;

Ec – cutting energy, J; A – cutting area, m2 [3].

Specific cutting energy per mass unit Esc for stalk material had been calculated using equation:

Escq E = , (2) sc ρ

-1 where: Esc - specific cutting energy per mass unit on the countershear, J m kg ;

ρ - reed stalk material density, kg m-3. These specific cutting energy values are the same order and can be used for calculations in cutting equipment design process. The cutting (chopping) energy Εcm for stalk biomass unit (kg) was calculated [4] using equation:

Esc Ecm = , (3) Lc

-1 where: Ecm – cutting energy per mass unit, J kg ; Lc – length of stalk cut, m. Experimental cutting device was designed specially for flattened stalk material cutting. Cutting device (Fig. 2a) consists of die 1 and knife 2. Flattened reed specimen 3 is fastened with plate 4 to die. Cutting using two types of knives – with edge angles 20° and 90° (Fig. 2b) had been investigated. Displacement, stress and energy consumption data were collected on computer.

Estimation of feeders for dosage of biomass was done by several criteria: precision of dosage; cycle (continuous, discontinuous); suitability for cohesive materials; efficiency; initial and operating costs; possibility to vary the flow rate over the required range. The most suitable for feeding the bulk material like cut reads, straw, peat, and other biomass previously was stated the screw feeder. The volumetric throughput Q of a screw feeder is given by [5]:

3 -1 QQ= tvη (m s ), (4)

Qt – maximum theoretical volumetric throughput with feeder running 100% full and the bulk material moving axially without rotation;

ηV – volumetric efficiency; The volumetric efficiency of a screw feeder is the product of two components as indicated:

ηVVRF=ηη, (5)

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where ηVR – conveying or vortex efficiency accounting for the rotational or vortex motion; h η = “Fullness” efficiency = av , (6) F p

hav – average height of material on the screw surface; p – pitch, m. Estimation of the volumetric throughput of a screw conveyor was carried out in experimental equipment. A feeder with vertically oriented screw was built. Screw diameter was 140 mm. Rotation frequency of the screw was changed by hydraulic drive. Peat with density 130 kg m-3 and moisture content ~10% was used for experiments. At the stated rotation frequency, the bulk material flowed out of the bin, and the time was fixed when the bin

was empty. Rotation frequency was increased and Fig. 3. Stalk particle and peat the experiment was repeated. composition briquettes A demand for density of solid biofuel briquettes and pellets is >1.0 g cm-3 in the standards of European countries [6]. This value had been used for evaluation of herbaceous material densification results. Densification experiments had been carried out in closed die by means of hydraulic press equipment. Wheat straw and reed stalk material biomass with moisture content of 10% were chopped to different length and had been used for densification. Experiments were carried out with particles from different fineness groups. Mixed peat and

stalk material particles were used as briquetting Fig. 4. Shear stress compositions. Maximal pressure 230 MPa had been measuring device 1 - punch, 2 – body, achieved in densification. Force and displacement had 3 – separator, 4 – bolt. been recorded in densification process and the calculations let to find the energy requirement for it. The briquettes (Fig 3.) with different density and ultimate shear stress had been obtained as result. For density calculation the weight and size of briquettes were measured. Wedge device was used for investigation of ultimate shear stress of briquettes in direction perpendicular to briquetting direction (Fig. 4). To provide sufficient precision and accuracy of measurements the virtual measuring equipment with 16 Bit ADC was used.

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Results and discussion Average energy consumption 0.8 J had been stated for unflattened single reed stalk cutting, but average energy consumption for flattened reed cutting was 0.38 J. The difference between flattened and unflattened reed stem cutting energy consumption was 0.42 J. From flattening experiments was stated that flattening energy consumption for reed stem with length 6 cm was 0.2 J. Therefore more economically is to use of flattened reed stems for cutting. It is simpler also for shredder design, because reed stem transporting can be realized with drive rolls.

Cutting energy consumption for two types of knives and flattened reed stem stacks had been stated. For cutting two and three layer stack of flattened reed stalks the knife with edge angle 90º showed twice more energy consumption than knife with edge angle 20º (Fig. 5). The differences were not sufficient in the specific energy values for single flattened reed stalk cutting (average difference was approximately 2.4 kJ m-2 for the two types of knives). Therefore for reed stalk cutting more favorable will be usage of single reed stalk layers and chopping with cutter which edge angle is 90º. If cutter edge angle is smaller, then cutter edge stays edgeless faster.

Sharpening of shredder knives can be serious problem during maintenance. There is possibility of choice during design process. If easy maintenance is preferred, then simple shape of cutter knife edge has to be used. The similar problem is for the choice of shape of cutter counter knives and it has to be solved accordingly. Specific cutting energy per area unit Escq for reed stalk biomass was not significantly changing in dependence of punch orientation angle according cross section of specimen (Fig. 6). Escq value varied in 8 – 16 kJ m-2, depending of stalk strength.

60

-2 50 Edge angle 90 degree

40 Edge angle 20 degree

30

20

10 Specific energy, kJ m

0 01234 Quantity of reed stems

Fig. 5. Reed stem specific energy consumption

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Reed stalk material particle size reduction during cutting (shredding) process increased energy consumption very significantly. Wheat straw and switchgrass grinding performance investigation [7] showed the same order values of energy consumption per mass unit. The grinds from hammer mill with screen size of 3.2 mm had a large size distribution with a geometric mean particle diameter 0.64 mm for wheat straw and 0.46 mm for switchgrass

25

20 -2

15

10 Energy, kJ m kJ Energy, 5

0 0 102030405060

Angle, Deg

Fig. 6. Reed stalk specific cutting energy grinds. Corresponding energy consumption for grinding is 40.9 kJ kg-1 for wheat straw and 85.8 kJ kg-1 for switchgrass. The calculation of energy consumption for common reed cutting to sizes 0.64 and 0.46 mm was giving results 31.25 kJ kg-1 and 43.48 kJ kg-1 (Fig. 7). Taking into account that common reeds have higher values of ultimate tensile and shear strength, this theoretical calculation, without energy losses from friction during shredding process, was giving feasible results. The shredder cutterbar have to be designed with friction energy losses decreased to minimum. This aim can to be realized by reducing of area of cutterbar knives moving into stalk biomass and minimizing biomass pressure on cutterbar. There is also possibility to cut down energy consumption for stalk material shredding by increasing the size of particles for compacting. Peat usage as additive improves densification properties of such increased size stalk material particles.

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-1 50 45 40 35 30 25 20 15 10 5

Energy consumption, kJ kg 0 0 2 4 6 8 101214161820

Size, mm

Fig. 7. Energy consumption for common reed cutting

It was stated that throughput of an enclosed screw conveyor is influenced by the rotational or vortex motion of the bulk material during transportation and the degree of fill or "fullness" of the screw. As the rotational speed of the conveyor increases, the rotational or vortex motion decreases up to a limiting value, making for a more efficient conveying action. However, when gravity feed system into the screw intake is employed, the feed rate cannot match the potential conveying capacity, and a reduction in fill ratio or "fullness" occurs [5].

Specific throughput (kg rev-1) of screw feeder practically remained constant at frequency

0.065

0.060 -1 0.055

0.050

0.045

0.040 Throughput, kg rev 0.035

0.030 135791113 Frequency, s-1

Fig. 8. Throughput of vertical screw feeder from 2 to 7 s-1 (Fig. 8), which is a usable range for precise throughput control.

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Fig. 9. Ultimate shear stress, briquetting energy and density of straw (2 – 3 mm) – peat (3 mm) briquettes

Recommended density of straw briquettes >1.0 g cm-3 had been obtained if peat proportion exceeds 35% (Fig. 9). In praxis when large amounts of particularly difficult biofuels (e.g. logging residues and used wood) are to be combusted, blends with up to 35% peat are used [8]. Pressing energy consumption for briquetting of chopped common reed and straw stalk material particles with peat showed maximal value ~ 40 kJ kg-1 (Fig. 9 and 10). It was stated, that average ultimate shear stress of straw briquettes was not dependent significantly from particle size for particles 0.5 – 3 mm and is ~0.2 MPa. Ultimate shear stress of straw and peat briquettes with fineness 0.5 – 3 mm increased from 0.2 MPa to 1.5 MPa by adding of peat (3 mm) in proportion 0–100% (Fig. 9). Ultimate shear stress of chopped (particles 1 - 2mm) reed briquettes was ~0.31 MPa (Fig.10). The density of reed (1 – 2) briquettes >1.0 g/cm3 had been obtained without peat. Adding 35% peat to read briquettes led to higher ultimate shear stress of the briquettes ~ 0.5 MPa, like briquettes from wood (3 – 5 mm) (Fig. 11). Ultimate shear stress of wood briquettes can be taken for example of sufficient durability of biomass briquettes.

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Fig. 10. Ultimate shear stress, briquetting energy and density of reeds (1 – 2 mm) – peat (3 mm) briquettes

Decreasing of particle size of stalk material or wood chips allowed increasing ultimate shear stress of briquettes. Wood chip briquettes with particle size less than 2 mm let obtain ultimate shear stress >0.6 MPa (Fig. 11). The same durability of reed briquettes could be obtained with particle size less then 0.5 mm. Ultimate shear stress 0.6 MPa for the straw briquettes could be obtained only by adding ~60% of peat.

0.8 0.7 0.6 0.5 0.4 0.3 Wood chips 0.2 Reed 0.1 Wheat straw

Ultimate shear stress, MPa 0 012345 Particle size, mm

Fig. 11. Ultimate shear stress on dependence of particle size

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Conclusions

1. The difference between flattened and unflattened reed stem cutting energy consumption is 0.42 J. 2. There are no sufficient differences (2.4 kJ m-2) in the energy consumption values for single flattened reed stalk cutting with knife edge angles 20º and 90º. Therefore thin herbaceous biomass layer cutting is recommended for shredder design. 3. Increasing the size of stalk material particles for compacting cuts down energy consumption for stalk material shredding. 4. Specific throughput (kg rev-1) of screw feeder practically remained constant at frequency from 2 to 7 s-1, which is a usable range for precise throughput control. 5. There is double advantage of using herbaceous biomass and peat compositions for briquetting, because recommended density of briquettes 1.0 g cm-3 is obtained and the formation of chlorides during combustion process is avoided. 6. Density 1.0 g cm-3 has been obtained in compaction of straw stalk material particle compositions with peat, if peat proportion exceeds 35%. 7. Pressing energy consumption for briquetting of chopped common reed and straw stalk material particles (size 1 – 2 mm) with peat shows maximal value ~40 kJ kg-1. 8. Wood chip briquettes with particle size less than 2 mm let obtain ultimate shear stress >0.6 MPa, but the same durability of reed briquettes can be obtained with particle size less then 0.5 mm, ultimate shear stress 0.6 MPa for the straw briquettes can be obtained by adding ~60% of peat.

References 1. Communication from the commission. Biomass action plan. Commission of European communities. -Brussels, 7.12.2005 COM(2005) 628 final. (10.02.2006) Available at: http://europa.eu.int/comm/energy/res/biomass_action_plan/green_electricity_en.htm 2. Terhi Lensu. Quality guidelines for fuel peat preparation started //Newsletter 2 on standards for bioenergy in the Baltic Sea Area.- March 2005.-Nordisk Innovation Centre. (10.02.2006) Available at: http://www.nordicinnovation.net/_img/newsletter2_final.pdf 3. Pahkala K, Pihala M. Different plant parts as raw material for fuel and pulp production., Elsevier Science B. V., 11 (2000) 119-128 pp. 4. Ajit K. Srivastava, Carroll E. Goering, Roger P. Rohrbach., Engineering principles of agricultural machines. ASAE: June 1993 – 601 pp. 5. A. W. Roberts. Design considerations and performance evolution of screw conveyors. http://www.saimn.co.za/Beltcon/Beltcon11/Beltcon1114.html 6. Woodpellets in Europe //htpp://www.eva.ac.at/(en)/publ/pdf/pellets_net_en.pdf 7. Mani S, Tabil LG, Sokhansanj S. Grinding performance and physical properties of wheat and barley straws, corn stower and switchgrass. Biomass and Bioenergy 2004; 339 pp. 8. Alkangas E., Lensu T., Haglung N., Nitschke M. Review of the present status and future prospects of standarts and regulations in the bionergy field. Nordisk Innovations Center. 2005. pp. – 58.

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MONITORING OF THE FIELD-TEST OF TWO WOOD LOG- BOILERS/STIRLING ENGINE COMBINATIONS

Ulrich Bemmann, Bodo Groß

IZES gGmbH, Institut für ZukunftsEnergieSysteme, Altenkesseler Straße 17 D- 66115 Saarbrücken, Germany

Key words: wood log-boiler, Stirling engine, hybrid plant, field-test, monitoring

1. Introduction

At present in the sector of one- and two-family houses the outweighing part of the necessary electricity is produced in centralised large power stations. The necessary heat energy is produced by means of boilers in the own house. Both takes place usually on basis of fossil fuels such as coal, natural gas and fuel oil. The efficiencies are thereby on the average under 40% electrical (average of German power plant-mix) and over 90 % thermally (domestic heating plants). This corresponds to an average loss of approximately 35 % related to the primary energy consumption.

The energetic use of wood is limited to small-scale units and to the production of thermal energy for heating purposes. However, in principle it is possible to convert parts of the combustion heat into electricity, e.g. using Stirling engines. This kind of decentralised combined heat and power generation is very interesting for the future, especially because of its higher efficiency as much as the CO2-neutrality compared to conventional systems.

The combined heat and power generation (CHP) is the most efficient possibility to use solid biomass.. While, in the range of more than 500 kWel, technically developed plant concepts already exist, the breakthrough is still missing in small range applications. The company HOVAL successfully advanced the development of a CHP plant which is performed as a wood log-boiler/Stirling engine combination in the last few years. The power output of the

HOVAL hybrid unit is about 1 kWel and up to 50 kWth.

The production of useful energy in small CHP plants, in particular with Stirling engines, reaches overall efficiencies of more than 90%. This corresponds to a loss of only 10% related to the primary energy employment. Resulting from this an average reduction of the primary energy consumption of approximately 25%, compared to conventional energy supply, can be reached using CHP units.

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The field test, including monitoring and scientific evaluation, wants to document on the one hand the everyday reliability of the wood log- boiler/Stirling engine combination; on the other hand it intends to point out optimisation potentials of the hybrid system.

In the forestry house Sulzbach, German Federal State Saarland (see figure above), one of the demonstration units is installed.. Operator of the plant is the SaarForst, whose is interested primarily in animating the commercialisation of wood logs combined with efficient energetic use of wood in Saarland. The main reason for the realisation of this project is to demonstrate the advantages of the innovative hybrid technology regarding the energetically use of wood logs. With the own unit the SaarForst would like to win concrete experiences with this technology.

2. State of the Art, Concept and previous development of Wood log boiler/Stirling engine combinations

Stirling engines are discussed for years as "the technology" for decentralised CHP-plants fired with biogenous fuels. Until now the vast introduction of the employed Stirling engines on the market was missing; among other things due to the (still) not solved task concerning the soiling of the primary heat exchanger and the therefore resulting high maintenance costs.

With priority, as possible fuels wood chips and wood pellets were nearer examined. For both fuels exists first demonstrations plants but there are still no “standard”-technologies available on the market. The combination with wood log was developed so far (to larger extent) only by HOVAL with success. On the test stand the desired technical conversion maturity with prospect to the necessary reliability of the overall system could be shown by making different tests. Also the permanent availability, the maintenance demand and costs for wood log-boilers, could be proven.

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Main goals of the conceptual design of the engine were on one hand a long life cycle and on other hand smallest maintenance costs.

The Stirling unit is designed as "ADD ON”- solution. That means that the Stirling engine and the boiler are two independent modules.

Within the conceptual design, the maximum electrical power output of the Stirling engine was rated for approximately 1 kWel within a wide thermal operating range.

In addition the "ADD ON" -solution makes possible to operate the boiler at any time without inserted Stirling engine. For this purpose the round opening, for the insertion of the primary heat exchanger of the Stirling engine, must be closed with an appropriate cap.

In a first test the fundamental function of this technology was examined on the test stand in the laboratory of HOVAL in Vaduz. For this, a Stirling engine with a coupled, net parallel operated threephase aggregate was integrated into a wood log boiler ,type HOVAL "PuroLyt". The used Stirling engine was developed by Dr. B. Kammerich from Dortmund, Germany.

In total, the hybrid unit was operated in this first test ~ 1,300 hours. After this first test the engine was completely deconstructed and examined to detect possible mechanical wear. The result was very joyous, because the engine was reassembled without changing any part.. In a second test the engine was operated for further ~ 1,200 hours in combination

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with the new Hoval- wood log boiler "AgroLyt" with Lambda combustion air regulation. Between May 2001 and November 2003 the engine was tested more than 2,500 operation hours.

In the following illustration the interconnection between the temperature of the Stirlings primary heat exchanger and the corresponding electrical power output is shown during a period of eight hours.

1000

900 electrical power [W]

800

700

600 temperature primary 500 heat exchanger [°C]

400

300 1 2 3 4 5 6 7 8 MesspunkteTime [h]

After this orientation phase a field test with several demonstration units for different applications was prepared. For this purpose, an extensive monitoring program for two plants, consisting of AgroLyt boiler and Stirling engine, in the context of a field test, was developed. Thereby special attention is payed on the general operability, the suitability for daily use, the different possible hydraulic concepts, emergency- cooling and –disconnection procedures, the optimisation of the mechanical adjustment of the engine as well as the boiler control concerning the Stirling engine-specific requirements..

3. Project description

Plant operator SaarForst, industrial partner HOVAL and IZES as project initiator and scientific leader of the project will examine the plant in Sulzbach (see illustration down) as well as a further location, concerning the following points:

• Availability & reliability of the plant components • maintance demand concerning cleaning, filling etc. • Influence of the fuel quality

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• Emission behaviour • Technical data concerning power Stirling/boiler, operating hours, energy balances, temperatures, variations of the capacity etc. • hydraulic integration requirements

For this, the plants are equipped with a monitoring system and will be measured over, at least, two heating seasons. The measurement data will be analysed and evaluated. The results of the monitoring are the basis for the further optimisation of the technology combination consisting of wood log-boiler and Stirling engine. The adjoining illustration shows exemplarily one possibility for the hydraulic integration of the Stirling engine into an existing system, including the engine cooling circuit. The primary cooling circuit of the Stirling engine is hydraulically decoupled of the remaining system for technical reasons by means of a heat exchanger.

The secondary cooling cycle of the Stirling engine is merged as in the example shown into the return of the complete system, in order to secure a permanent heat demand.

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With the results of the monitoring program the basis is prepared for a broad introduction of this technology on the market. At the same time, possible "weak points" of the entire plant in the everyday life operation are identified. This leads to the identification of potentials of optimisation regarding availability and management of the plant. The won experiences, particularly regarding a first small series production, are implemented by a following renewed revision of the engine construction. Furthermore, the field test makes possible a technical and economic evaluation of the chances of success, which can serve as basis for calculation; thus, the advantages for the end customer become more transparent.

4. Acknowledgment

The described project is carried out on basis is supported by the Federal Ministry for nutrition, agriculture and consumer protection under the promotion code FKZ 22017605.

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Investigation to the energy production potential of biomass in proportion to energy demand of the administrative district of Güstrow

*Dr. Mathias Schlegel (1), Dipl.-Ing. Torsten Rehl (2), PD Dr. Norbert Kanswohl (1) (1) Institute for Productive Livestock Animal and Technology, Faculty for Agricultural and Environmental Sciences, University of Rostock, Germany (2) Institute of Agricultural Engineering in the Tropics and Subtropics, Institute of Agricultural Engineering, University of Hohenheim, Germany

Introduction Since beginning of the industrialisation around 1780 the developments in economy, science and technology became possible primarily by the becoming lighter availability of necessary fossil energy sources. Scheer [1] calls the today's world economy so also fossil. In this connection the being of borders of the energy availability becomes clearly. Beside physical borders there are also political imponderabilities. Thus about 70 percent of the conventional oil reserves are in a relatively narrow area (figure 1). This area ranges from the Middle East about the caspian space to northwest Siberia, marks partly politically unsafe regions from which for Germany itself a strategical dependence of his national economy proves.

strategical ellipse

Figure 1: Distribution of the oil and natural gas reserves of the world in lands with reserves > 1 Giga metric ton (Gt) and “strategical ellipse” [2] The varied insecurity compared with the availability of energy causes those energy price increases which each could observe during the last years on the stock exchanges and feel in own energy costs. This development led to a reinforced reflexion about alternatives in the energy industry. Also the use of biomass plays an important role in those considerations.

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Nevertheless, in contrast to the other renewable energy their use will have to walk along with a change to more decentralised structures, because the energy in biomasses is in relatively low density and to themselves forbid with it longer routes of transport for ecological however also economic reasons. Therefore there is a necessity of the reinforced integration of the energetic use of biomasses in the energy industry. It can be given reasons for the motive of national economy. Apart from this motive good possibilities of development arise for business circles existing of regional level. The question to the substitution potential of bioenergy sources compared with conventional energy sources must be answered at first by indicating the available biomass stocks and their specification on the regional level. For example, the logistic structures should be developed later from it for the development of these potentials. The already available studies to biomass potentials [3, 4] are only partly transferable because of their specific regional specific features, the different relations (surface yields, energy contents, registred biomasses, …) or their dynamism. So a relevant investigation was carried out for the administrative district of Güstrow and this aspect was extended by the comparison with the energy demand at this local or regional level.

Material and Method

The examined region (administrative district of Güstrow) belongs to the federal state Mecklenburg-West Pomerania (figure 2), to one of 16 federal states of the Federal Republic of Germany. The administrative district lies with his surface of 2.058 km ² in the centre of Mecklenburg-West Pomerania. He shows at the time of this publication a population density of 53 habitants/km² [5] what is very low in contrast to that of Germany (231 habitants/km²). The environs of the cities and places of the administrative district still lie underneath with less than 40 habitants/km².

The proportion of the wood in the administrative district lies at approx. 17 and that the agricultural land at approx. 71%, in contrast to the proportions in Germany: wood with 29.5% as well as agricultural land with 53.5 % [6]. The administrative district is climatic stamped by an annual means temperature of 9 °C (in May-September: 14 -15 °C) and by the crossing of the sea climate in the northwest in the continental climate in the east. The amount of precipitation lies between 550 and 650 mm per year. The administrative district of Güstrow is made up of 66 (before 2005: 74) municipalities which are administered by 8 (before 13) offices (Bützow, Güstrow, Laage, Teterow, Bützow country, Gnoien, Güstrow country, Jördenstorf, Krakow am See, Lalendorf, Steintanz-Warnowtal, Teterow country). The forests

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are administered by three offices: Güstrow, Schlemmin and Dargun and their arrangement does not agree with the administrative borders of the administrative district.

Figure 2: Administrative overview Mecklenburg-West Pomerania with all administrative districts (administrative district of Güstrow emphasised) [7]

For the elevation of these data the following institutions were contacted: - Ministry of the environment and ministry of economics of Mecklenburg-West Pomerania - Office for regional planning Middle Mecklenburg/ Rostock - Regional authorities for environment and nature Güstrow M-V - Statistical regional authorities, farmer federation of Güstrow - Waste economy office Güstrow - Recycling courts - Residual wood disposal agencies - Waste disposal agencies - Wood-processing industry - Eurawasser GmbH and - Plant operators

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Because the investigation deals with complicated systems hardly to be overlooked and the concepts linked with it, it is necessary to the understanding and comparability to define in the following the concepts biomass, bioenergy source and different potential concepts: „Biomasses for the purposes of the ordinance are energy sources from phytomass and zoomass. Following products and by-products, remains and rubbish resultant from phytomass and zoomass, whose energy content comes from phytomass and zoomass also belong to biomass. [8] The concept of the bioenergy source looks at biomasses as energy storage which can be generated warmth, electricity and mechanical power. Solid, liquid and gaseous bioenergy sources can be distinguished: The concept of the biomass potential is used in the literature very differently and needs a unification [9]. Caused by the high number of determinants and factors of influence different potential concepts take over the task of the demarcation (figure 3).

Theoretical energy potential Max. upper limit of area, soil / energy content Technical energy potential Available technologies, harvest, transport, storage, laws / degree of efficiency Economical potential Costs of competing energy carrier, energy price Deducible potential development

Ecological aspects, acceptance problems, institutional restraints

Figure 3: Demarcation of the different concepts of potentials [10]

The theoretical energy potential calls after scientific legitimacies the basically available energy, regardless of technical and organizational obstacles. The technical energy potential describes that proportion in the theoretical energy potential which is usable taking into account the given technical, structural, ecological and legal restrictions (available technologies of utilisation, efficiencies of the energy conversions, availability of locations, also in view of competing uses, as well as structural, ecological and other restrictions). The economic potential shows the proportion of the technical potential which can be opened economically by consideration of all competitive energy sources and energy systems. The deducible potential is the proportion of the economic potential which can be opened under the real conditions (restricted capacities of the investment manufacturing, still existing old plants, other obstacles like deficits of information, juridical and administrative borders).

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Within the scope of the investigation a huge number of bioenergy sources was registered what the following subdivision should help to assign them to the solid, liquid or gaseous energy sources:

Agriculture Forestry Landscape Money of public Industry and conservation authorities trade

• agricultural • Biotop nursing • Old wood • Forest rest wood • Communal culltivation • Streets • Industry rest loppings • Residuals from • Weak wood • Trackage wood livestock • Shores • Biowaste • Used wood • Firewood • Special farming • Margin • Loppings • Sludge cultures structures • Biowastes, food • Tree nurseries • Private loppings • Organic rests rests • Vegetable and from domestic • Sludge fruit cultivation waste

Main product Linked product Main product Linked product Main product Linked product • wood-like • Wood-like • Oily biomass • Altmethylester biomass biomass other biomass • gasification of • thinning wood • By-products • plant oil (rape • Old oil solid biomass • Manure • forest rest by sawing oil) Old grease wood • Old wood • • muck • RME • Landschafts- • stalk-good- • mud of old • Bio waste pflegeholz natured lye and • Kurzumtriebs- biomass sewage • Sludge

holz • straw

Solid Liquid Gaseous

Figure 4: Biomass potentials according to the producers and their change forms in solid, liquid and gaseous energy sources [11]

The solid, gaseous, liquid bioenergy sources can be converted into electricity and warmth. For it the technical energy potential is determined at first and of course the different degrees of efficiency of the respectively possible conversion plants are essential. The technical energy potential serves as a base to calculate the technical production potentials for electricity and warmth. This is confronted with the ascertained energy demand in electricity and warmth (figure 5). The confrontation has to answer in particular the potential proportion of the bioenergy in a future energy source mix.

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Regional-, municipial- and production Areas and their use structure

Forestry biomass Agricultural biomass Communal biomass

Offer of regional bioenergy sources (theoretical & technical potential)

Energy offer of regional bioenergy sources (theoretical & technical potential)

Present energy offer of Supply structure of energy Bioenergy- fossil and regenerative market energy sources

Potential of biogenic satisfied demand

Demand of electricity and warmth

Private Agriculture Industry and trade Smal consumer Sectors

Figure 5: Formation of the bioenergy market by energy demand and offer of bioenergy [11]

Results For the whole administrative district of Güstrow a theoretical energy potential (primary energy content) was determined by 6,037 PJ/a. Of it 57.1% are from stalk-good-natured biomass, 21.5% are from gaseous bioenergy sources, 15.1% are from wood-like bioenergy sources, 5.4% are from liquid bioenergy sources and 0.8% from municipal gaseous bioenergy sources In the sum the solid bioenergy sources dominate with almost three quarters of the whole potential. In order to confront the values of energy demand of the administrative district Güstrow (warmth: 4,542 PJ/a, electricity: 1,164 PJ/a), likewise ascertained in this investigation, with a comparable value of bioenergy offer, a use in conversion plants (thermo-chemical, physical-

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chemical, biochemical conversion) must be subordinated for the ascertained primary energy content with accordant degrees of efficiency. Then the technical energy potential arises from it. From these calculations can be held on, to sum up (Table 1) that 9 of 13 offices would be able potentially to cover her energy demand by bioenergy source from own area. Table 1: Energy demand and potential offer of bioenergy City, Energy Demand Offer Difference Pot. cover office type after of the demand conversion with the offer [GJ/a] [%] Bützow-city Warmth 346.730 31.715 -315.015 9 Strom 88.902 8.270 -80.632 9 Güstrow-city Warmth 1.318.115 66.661 -1.251.454 5 Strom 337.967 17.134 -320.833 5 Laage-city Warmth 223.616 128.019 -95.597 57 Strom 57.336 30.984 -26.352 54 Teterow-city Warmth 408.098 91.089 -317.009 22 Strom 104.637 19.915 -84.722 19 Bützow-country Warmth 269.096 424.408 155.312 158 Strom 68.996 109.930 40.934 159 Gnoien Warmth 293.433 480.336 186.903 164 Strom 75.237 113.608 38.371 151 Güstrow-country Warmth 378.297 418.060 39.763 111 Strom 96.996 106.190 9.194 109 Jördenstorf Warmth 232.654 428.372 195.718 184 Strom 59.652 107.375 47.723 180 Krakow am See Warmth 258.545 274.488 15.943 106 Strom 66.292 72.294 6.002 109 Laage-country Warmth 203.356 278.839 75.483 137 Strom 52.141 65.214 13.073 125 Lalendorf Warmth 180.742 234.426 53.684 130 Strom 46.343 56.382 10.039 122 Steintanz- Warmth 225.633 298.980 73.347 133 Warnowtal Strom 57.853 73.873 16.020 128 Teterow-country Warmth 203.987 315.785 111.798 155 Strom 52.302 85.801 33.499 164 Administrative Warmth 4.542.305 3.492.618 -1.049.687 77 district Güstrow Strom 1.164.654 857.521 -307.133 74

Only at the red emphasised offices Bützow city, Gustrow city, Laage city and Teterow city the energy demand is higher than the technical energy potential of biomass. See the last both lines of the table, the administrative district of Güstrow can cover the energy demand with own biomass of 77% in the warmth and of 75% in the electricity. As a reason for this high degree of cover the regional circumstances should be called. On one side a high proportion of agricultural and forest areas can be distinguished, that increases the biomass potential. On the other side the relatively low population density which leads in comparison to the dense settled cities or conurbations to a lower energy demand is to be stated. For the offices in those a positive degree of cover exists (green emphasised), remains as a criterion

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for the establishment of a bioenergy plant the question after their size. It have to correspond approximately with the energy demand of local level. At the time of the investigation (2005) only 1% of the available technical energy potential was used in the administrative district of Güstrow. With it the considerable substitution possibility of the administrative district is to be held on and in this connection the fields of the logistics, the location choice, the energy and material balances etc. still considerable research need.

References [1] Scheer, H.: Solare Weltwirtschaftg von Biomasse im Landkreis Güstrow, Diplomarbeit, Universität Rostock, 2005- Strategie für die ökologische Moderne, Verlag Antje Kunstmann, München 1999, ISBN 3-88897-228-0, 352 S. [2] http://www.bgr.bund.de/cln_030/nn_461658/DE/Themen/Energie/Bilder/ Ene__Erdoel__allg__BILD2__g.html, download 05.10.06) [3] Leible, L.; Kälber, S.; Kappler, G.: Entwicklungen von Szenarien über die Bereitstellung von land- und forstwirtschaftlicher Biomasse in zwei baden- württembergischen Regionen zur Herstellung von synthetischen Kraftstoffen, Studie im Auftrag der DaimlerChrysler AG/ Abschlussbericht – Juni 2005, Forschungszentrum Karlsruhe GmbH, 42 S. [4] Fritsche, U.R.; Dehoust, G. et al: Stoffstromanalyse zur nachhaltigen energetischen Nutzung von Biomasse, Verbundprojekt BMU, Darmstadt, Berlin, …, 2004, 263 S. [5] Stat. LA M-V: Statistische Berichte. Bevölkerungsstand der Kreise, Ämter und Gemeinden in Mecklenburg-Vorpommern, Stichtag 30.06.2004 [6] Statistisches Bundesamt: „Flächenerhebung 2001“, Stichtag 31.12.2000 [7] http://www.lverma-mv.de/, download 06.10.06 [8] EEG: § 2 Abs. 1 Satz 2 vom 01.01.2001/ BGBl I 2001, 1234 [9] Kaltschmitt, M., Merten, D., Fröhlich, N., Nill, M.: Energiegewinnung aus Biomasse, Externe Expertise für das WBGU-Hauptgutachten "Welt im Wandel: Energiewende zur Nachhaltigkeit" Berlin, Heidelberg 2003 Hrsg.:Institut für Energetik und Umwelt gemeinnützige GmbH, veröffentlicht als Volltext im Internet unter http://www.wbgu.de/wbgu_jg2003_ex04.pdf, 2003 [10] Darstellung Rehl in Anlehnung an Energie Agentur Lippe: Handlungskonzept Holzenergiehof Bergisches Städtedreieck, S.8, 2004 [11] Rehl, T.: Untersuchung der energetischen Nutzung von Biomasse im Landkreis Güstrow, Diplomarbeit, Universität Rostock, Agrar- und Umweltwissenschaftliche Fakultät, 2005

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Development of Unutilized Biomass Potentials in Forestry and Landscape Conservation: Logistical Challenges and Potential Uses of Innovative Telematics Technologies and Services

Dr.-Ing. Ina Ehrhardt, Dipl.-Wirtsch.-Inf. Mike Wäsche Fraunhofer Institute for Factory Operation and Automation IFF, Magdeburg, Germany

Introduction Among other things, the heterogeneity of the types, quantities and numbers of potential sources and sinks as well as the means of transportation used continue to make it difficult to describe as a whole logistics processes for developing raw material in forest and field, especially for the wood processing industry, or for recovering renewable energies. Conventional methods of logistics controlling and measurement only capture these processes incompletely and partially. Innovative developments in the field of mobile information technologies are opening tremendous potentials for improving logistics processes. Taking into account the multitude of national and international standards and guidelines in this field, catchphrases such as location based services or LBS and radio frequency identification or RFID already stand for effective and practicable solutions in traditional fields of application for logistics. While the aforementioned technologies are on the threshold of entering the mass market in commerce or at large logistics service providers, motivated by reports of success in the sectors mentioned, the use of LBS and RFID to support wood and biomass logistics is still in the phase of initial successful testing and pilot projects. Here, everyone involved in the process is confronted by the challenge of effectively communicating not only the successes and potentials but also existing restrictions to a broad audience and publicizing needs for development. Building upon RFID and telematic trends and applications in classical fields of logistics, this paper presents current successes and addresses further needs in the forestry and wood processing industries as well as related sectors. The following theses are put forth for discussion: • The use of RFID and telematics must guarantee a quantifiable benefit for everyone involved in a process. • The development of a broader range of solutions customized for individual cases and preconfigured will help the technology to a breakthrough more than striving for the universal solution will.

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• Standardization is a fundamental prerequisite to user acceptance in general and investment protection, particularly for smaller enterprises.

Potentials and Restrictions of the Development of Biomass from Forestry and Landscape Conservation Promoted by such instruments as the Renewable Energy Sources Act, various government development programs and the legal regulations to boost the utilization of renewable energies in the heating market currently under discussion, a noticeable increase in the utilization of sources of bioenergy is foreseeable in the next ten to fifteen years. While these developments are currently in their infancy, particularly in Eastern European countries, the proportion of renewable energy in Germany – even based on biomass –is already steadily increasing. As exemplary analyses and current market developments demonstrate, the utilization of biomass is already generating conflicts of use for the already scarce resource of wood biomass. While special recyclers of energy are supplied high calorific biomass at the expense of established material flows and logistics processes, e.g. for the lumber industry, potentials lie idle elsewhere. Now as before, biomasses produced by forestry and landscape conservation usually remain unused at their point of origin. Apart from regional and hitherto rarely successful attempts by individual firms to establish isolated applications, no convincing overall concept for developing conservation residues and wastes is currently not known, which integrates technical feasibility, economic expediency, ecological compatibility and logistical effectiveness. Against the background of fluctuating prices on the raw materials market, rising logistics costs and fluctuations in the supply industry, both private individuals and companies are being compelled to hunt for new sources of raw materials and income as well as new service sectors and products.

Wood biomass is becoming more important for renewable energy recovery

X 12 mill. m3/a Residual wood in forestry X 7 mill. m3/a Forestry conservation wood X > 5 mill. t/a Landscape conservation wood X n. n. Other Landscape conservation wastes

Undeveloped potentials of woody biomasses

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The specific properties of biomasses relating to quality (heterogeneous structure, geometry, water content, purity of grade, etc.), quantity, locality and concentration generate obstacles and barriers, which neither allow developing these energy sources in agriculture and forestry cost efficiently nor with a positive energy balance. There are a variety of barriers, for example: • Restrictions on the use of technology impede the use of classical processing techniques. • Commercially active and potential service providers both have information deficits with regard to regional buyer structures and their quality requirements. • Decentralized resource structures and sites limit the opportunities to sell accumulating quantities of heterogeneous substrates regionally. • The possibilities of mixing and balancing assortments by relying on buyers of different qualities are limited. • The technology used by forest and landscape conservation service providers is frequently inappropriate for the quantity, cost, location and assortment of the biomass and hence cannot be used cost effectively for processing. • Buyers of heterogeneous biomass from forest and landscape conservation have been limited and the product costs generated do not (yet) cover the expenses of recovery, especially the logistics, i.e. the expenses are greater than the revenues. Formulating strategies, models and solutions to develop previously undeveloped high grade residual biomass from forestry and landscape conservation requires the close cooperation of everyone involved, i.e. producers, buyers, processors and transport logisticians. Only the close cooperation of these actors will make it possible to develop assortments suitable for utilization, incorporating regional locational factors, cost effective logging, transport, storage and handling technologies and supply strategies geared toward buyers. Innovative information and communication technologies, which are one focus of research and development work at the Fraunhofer IFF and have already entered many other areas of complex logistics chains, can also substantially contribute to cost effectiveness and efficiency as well as to environmental compatibility and ecology. Hence, the rest of this paper specifically addresses the potentials of and restrictions on the use of telematic applications employing LBS and RFID, which already represent effective and practicable solutions in various traditional fields of application for logistics.

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Biomass Logistics Belongs to and Supplements Wood Logistics: Potentials of RF and Telematic Technologies A large number of projects have been initiated and carried out in the recent past to develop solutions for more transparency and more reliability of information, i.e. for integrated planning, control and monitoring of the logistics processes supplying wood from the forest to the factory. Though often very slowly, the results are gradually being or already have been selectively implemented in commercial practice. Many times, heterogeneous IT infrastructures, inadequate interface standards and hardware and software incompatibilities constitute the key obstacles that lead to a lack of acceptance on the part of smaller partners who should be integrated and to reticence in larger concerns to invest in purchases and implementation projects. Model logistics solutions are completely nonexistent for logistics processes developing and supplying residual wood and biomass for energy recovery, which accumulate during forestry and landscape conservation work or nature conservation and cleanup. Potentials lie idle here, which could be rapidly developed by transferring and adapting existing approaches from wood logistics. On the one hand, transferring the approaches would generate values added for forest owners and forest service providers, e.g. by providing broad IT support to all core work processes as well as by refinancing expenses for conservation and supply. On the other hand, relieving the round timber market would sustainably support the wood processing industry. Taking into account the specific challenges in wood and biomass logistics such as: - The properties of wood and biomass as goods (shape, weight, volume), - Their harvesting with manual, semi- and fully automatic processes at distributed, constantly changing sites, - The harvesting of heterogeneous quantities and assortments for different channels of subsequent processing at different individual sites, - Weather influences (harsh environment), - Cyclical changes of the infrastructure (route restrictions, protected areas, weather) and the large number of different actors involved in the process, the difficulties and problems to be resolved primarily involve: - Locating (intermediate) storage sites, i.e. search times in forest and field, - Identifying assortments in terms of producer and buyer, - Minimizing losses of quality and quantity caused by discrepancies between what is recorded at the site of production and at the buyer’s facilities, - Reducing remainders after transport and - Preventing losses due to unauthorized transport or theft.

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These points are only aspects of all the deficits the actors have to deal with and eliminate in varying degrees.

Trends in Logistics: Radio Technologies Capture the Logistic Asset Subsumed in the concept material internet, one trend in logistics is monitoring and assessing the status and condition of mobile logistic assets in relation to their surroundings. This is a matter of uniquely labeling, localizing time-based and capturing the status and/or condition of goods, carriers, handling equipment and means of transport as well as individuals as a fundamental prerequisite to identifying motion sequences, sequences and local concentrations of logistic assets as the foundation for assessing internal and inter- enterprise logistics processes. Telematics and RF technologies are innovations driving the development of the material internet. Telematics combines telecommunication and informatic technologies. Radio frequency identification or RFID uses radio technologies to automatically identify and localize assets.

Information on the type, quantity, current position and status/condition of identifiable logistic assets (goods, handling equipment, loading equipment, means of transport, individuals, infrastructure) as well as the near real-time availability of this data in scheduling systems are assuming a central role in logistics. Accompanied by trends toward miniaturizing equipment and mobilizing the exchange of electronic information while simultaneously cutting costs, new markets are opening for autonomous logistic assets equipped with communication modules and sensor systems to optimize operational and logistics processes.

Telematic Applications and RF Identification for More Transparency in Wood and Biomass Logistics Just as in other sectors, the use of RF and telematic technologies in inter-enterprise processes developing, supplying and processing wood and biomass generates significant beneficial effects from the perspective of logistics. The following general aspects are directly related to the aforementioned challenges: - Detection of quality and status of logistic assets (e.g. wood and biomass) and the related jobs (harvesting – storage – transport), - Representation of a secure delivery chain outside companies and beyond national borders (proof of origin), - Clear identifiability of logistic assets (assortments, units of goods, human resources, tools, etc.) at any point in the logistics process,

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- Clear determination of location (localizability) and traceability (as well as retraceability) of logistic assets, - Route guidance for logistic assets to the last meter, even off public roads. These are augmented by beneficial aspects pertaining to the specific need situations of users in the forestry and wood processing industries and of biomass providers and users. Telematics and RF technologies improve the exchange of information in the following ways: - Processes are securely executed, e.g. through • Increased process efficiency (prevention of media breaks and duplicated records), • Failsafe process automation, • Accounting reliability, • Completeness (complete transport away), • Status/condition monitoring (status reporting) and • Situation-based control (weather, protected times, etc.). - Assets are distinctly identified of (e.g. proof of origin for certification, allocation of qualities and quantities to types of ownership and lands). - Assets are clearly localized (e.g. sites, stocks, storage site, equipment, human resources, transport units). Reports of successful telematic and RF use by retailers, logistics services providers or carmakers have had an impact on the forestry and wood processing industries, despite skepticism here and there about the applicability of these technologies under their specific conditions. Thus, reports of increased sales and reduced losses due to theft or minimized search times, decreased losses of material and enhanced accounting reliability have led to RFID becoming established in wood logistics processes. Successful industrial implementations of RF identification of individual trunks for subsequent processing in the sawmill industry [1] support assumptions that, on the one hand, forestry and wood processing industry users’ interest and demand will grow and that, on the other hand, medium-sized enterprises in particular will develop and offer RFID products as the economic motivation increases. Supplemented by results from pilot projects to reuse and subsequently use installed tags in the process flow, RF and telematic solutions in the forestry and wood processing industries promise competitive advantages for all the problems still open.

Important for Broad Acceptance: Creating Values Added for Everyone Involved in the Process The technology drivers RFID and telematics are also generating improved conditions and expanded options for using logistics platforms for the planning, control and monitoring of

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wood and biomass supply chains. As pilot projects have also demonstrated [2], advantages for the different parties involved in the logistics process are specifically generated whenever such platforms are based on integrable and integrating technical infrastructures, on the interplay of individual, universal and industry-specific software tools and on adaptable services. The execution of the complete logistics process does not constitute the core task for any of the actors in the wood or biomass logistics process. This is an important point and absolutely must be allowed for in any solutions developed. Individual tasks that have to be executed between actors in this process are connected with the respective core tasks and internal processes in completely different ways. Consequently, not only the connections to internal information systems but also – and far more importantly – those internal processes with which additional value added can be generated differ from actor to actor. When a financially and functionally appropriate range of services for all users of logistic platforms is supplied, the identification and systematic support of these core tasks will be the criterion of evaluation, which ultimately determines a solution’s quality. The financially and functionally appropriate services demanded include scalability and modularity as well as also “healthily” competitive services as alternative solutions. Along with automating the identification of raw materials and thus order and accounting management, RF and telematic functionalities in the forestry and wood processing industries as well as in landscape conservation and energy production are increasingly improving the management of stock and the continuous determination of the location and status of basic components of logistics such as harvesting, handling and transport equipment, human resources and road infrastructures. However, implementing integrated applications based on RF in wood logistics presupposes further developments in - Transponders, e.g. on specific carrier materials as well as – for wood processing – in appropriate sizes or for reuse (reusable transponder), - Methods for placing, applying and securing as well as removing transponders (manually, semi- and fully automatically), - Coupling transponders with sensors, e.g. to monitor equipment or the quality of wood storage, - Technologies for reading tags (development of universal readers, antenna technologies to boost range and technologies to capture group data) and - Positioning systems adapted for the harsh operating conditions from a cost and handling perspective. In view of the different requirements on the level of detail of process monitoring, the different motivations for identifying different assortments and the costs of identification, data acquisition and processing, the widest variety of transponder designs and types will

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presumably be engineered for individual applications in wood and biomass logistics. Driven by demands for cost effective customized solutions, a development that leads to a range of services appropriate for the sectors analyzed will help this technology make a breakthrough more than striving for the universal solution for wood and biomass logistics will. Only the combined use of this technology in the different processes of every single actor will generate the values added that justify investments in the requisite technical infrastructure (hardware and software) involving all the actors.

Standardization as the Prerequisite for Acceptance and Investment Protection In sectors such as retail and parcel services, RF technology is on the threshold of entering the mass market. These sectors are making great efforts to create a stable, standardized environment for implementing this technology in the entire value added chain. To this end, users are forming strategic partnerships to establish close ties between hardware and software developers and users. These two sectors are jointly endeavoring to standardize RF based applications, technologies and products to make it easier for companies to start using this technology and to clearly communicate its benefits. Precisely this action should serve as a model for further steps toward utilizing the potentials of new technologies in the forestry and wood processing industries. Effectively continuing developments will necessitate dialog among the actors themselves and with the providers of research and development services to formulate and concretize other need situations and to prioritize fields of application and processes. Supplementing these dialogs with standardization efforts will be imperative. However this must involve more than merely standardizing the exchange of information by defining data and data formats. More than before, the industry has to work toward standardizing hardware and software components as well as processes as work flow descriptions. The range of RF technologies and mobile equipment as well as software applications and services already commercially available and being developed have such a broad spectrum of features they are usually incompatible for combination into individual applications. In the long term, the different tasks and requirements the actors have for logistics processes in forest and field also necessitate scalable, customized solutions based both on technology and cost. In this respect, standardization is a fundamental driver behind further developing integrated logistics chains and will be a fundamental prerequisite to the acceptance of innovations and naturally to the protection of investments too. The LICON consortium (www.licon-logistics.com) has taken up different industries’ standardization efforts with the goal of establishing industry-based guidelines for secure chains of goods. The LICON group’s fundamental work involves establishing industry standards, bundling industry interests and specifying requirements for logistics processes

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supported by RF that have to be met to receive LICON certification. These industry requirements are being used to develop inspection and test plans to verify that processes, technologies and applications comply with LICON requirements. Organizations such as the VDI or VDA are already setting the standards for telematics. The actors involved in the processes of wood and biomass logistics would be well advised to do the same.

References [1] Im Odenwald funkt es, LOGISTIK inside, July 2005 [2] Integrierte Logistikketten für die Holzbranche, Holzzentralblatt, Friday, July 15, 2005

Author Information Dr.-Ing. Ina Ehrhardt, Fraunhofer Institute for Factory Operation and Automation IFF, Magdeburg, Tel. +49 (0)391/4090-811; [email protected]) Dipl.-Wirtsch.-Inf. Mike Wäsche Fraunhofer Institute for Factory Operation and Automation IFF, Magdeburg, Tel. +49 (0)391/4090-364; [email protected]

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Potential and limiting factors of biomass energy – Estonian experience of Short Rotation Forests

Dr. Andres Koppel, Dr. Katrin Heinsoo* Estonian University of Life Sciences, Tartu, Estonia

Analyses and strategic plans foresee the increased share of energy crops in European renewable energy sources [1, 2]. Willow (Salix) Short Rotation Forests (SRF) are one of the most promising crops for renewable bioenergy production in the boreal region.

In order to analyse the economic feasibility of bioenergy production, one of the key issues is how big is the production potential of energy crops and what are the limiting factors of biomass productivity. Besides the biological constraints to productivity, there are several technical and non-technical barriers to the wider use of SRF in different regions.

Extensive data on willow SRF productivity have been collected during the last two decades. Sweden has been the pioneering country in willow SRF research. The initial reports from mid 80-s on willow productivity were very optimistic, showing annual production of 20 t of dry shoot biomass per hectare per year in South-Swedish climate conditions [3]. However, the following research showed that these high production figures are rather exceptional. In the plantations without any visual damages to the plants above-ground shoot productivity reached 12…15 t ha –1 [4]. The recent studies have reported even lower annual production figures (around 10 t ha –1) in optimal growing conditions [5].

Willow productivity studies in Estonia extended over 10 years have demonstrated the same range of variability (the detailed analysis of productivity estimation methods and yield variation is given in Heinsoo et al. 2002). For practical economic planning the realistic production figures should be used as guidelines. The production potential of willows in optimal conditions is very high. In the experimental plantation the highest annual shoot productivity in one Salix dasyclados clone exceeded 24 t ha –1. Over the whole rotation cycle the average annual production of the same clone was 15 t ha –1. The average productivity of seven willow clones in the same plantation during the same rotation cycle was 11 t ha –1 and 5 t ha –1 for fertilised and non-fertilised plots, respectively. These figures could be used as rough guidelines for willow production in Estonian climate conditions.

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One of the typical findings in the willow production studies is the high variability of shoot yield. This phenomenon points to the possible way of establishing the limitation mechanisms. This variability is caused by several biological, soil and climatic factors: water and nutrient availability, attack of pathogens and pests, suitability of planting material to local climate conditions, early and late frosts, weed competition in the plantation establishment phase etc.

Beside the biological/direct limitations to biomass production in the SRF there are several non-technical barriers, which hinder the use of biomass for energy purposes. These limitations could be divided into non-technical and technical barriers. According to our latest applied research [7] the non-technical barriers are mainly the following: unstable/not established market of planting material, high planting cost, fertilisation limitations (legislative standards not established for energy crops), lacking subsidies, lacking extension system for farmers, market uncertainty.

Most of the non-technical barriers could be overcome by longer expertise on regional level and by special governmental support activities.

There are also some technical barriers which limit today SRF biomass production in Estonia: lack of domestic planting material which should be the most suitable for local conditions, absence of suitable harvesting equipment.

Due to the increased interest in biomass energy in Estonia the problems hindering development of SRF will likely be solved in the nearest future and these crops will find considerable share in the mix of energy sources.

Literature

[1] EC: Biomass action plan, COM 628 final, 2005 [2] Ragwitz, M.; Schleich, J.; Huber, G.; Resch, G.; Faber, T.; Voogt, M.; Coenraads, R.; Clejine, H.; Bodo, P.: Analysis of the EU renewable energy sources’ evolution up to 2020 (FORRES 2020), Fraunhofer IRB Verlag, 2005 [3] Christersson, L.: High technology biomass production by Salix clones on a sandy soil in southern Sweden, Tree Physiology, pp. 261-272, 1986 [4] Verwijst, T.; Elowson, S.; Li, X.; Leng, G.: Production losses due to a summer frost in a Salix viminalis Short-rotation Forest in Southern Sweden, Scandinavian Journal of Forest Resources 10, pp. 104-110, 1995

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[5] Aronsson, P.; Heinsoo, K.; Perttu, K.; Hasselgren, K.: Spatial variation in above- ground growth in unevenly wastewater-irrigated willow Salix viminalis plantations, Ecological Engineering 19, pp. 281-287, 2002 [6] Heinsoo, K.; Sild, E.; Koppel, A.: Estimation of shoot biomass productivity in Estonian Salix plantations, Forest Ecology and Management 170, pp. 67-74, 2002 [7] www.biomass.info

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BIOMASS POTENTIAL FOR HEATING AND ELECTRICITY PURPOSES IN POMERANIAN REGION

Prof. Dr. hab. Dariusz Mikielewicz* (1), mgr inż. Jan Wajs (1), Dr. inż. Edmund Wach(2) (1) GUT - Gdansk University of Technology, Poland (2) Baltic Energy Conservation Agency, Gdansk, Poland

ABSTRACT In the paper presented is analysis of potential for use of renewable energy for heating purposes in Pomeranian Province. Each municipality has been evaluated with respect to its potential of RES. Two of municipalities feature a fact that they have a potential to cover their heat demand with straw only, that means that it can be regarded as a potentially 100% covered with heat produced from straw fired boilers. One of them will be discussed in detail.

1. INTRODUCTION

The Polish energy sector is based mostly on coal and coke. Ca. 75% of primary energy is produced from coal, which causes quite serious air pollution. Highly developed countries have a share of coal in consumption of primary energy not exceeding ca. 30%. Poland therefore has high dust emissions (6,2 t/km)2 per year) and sulfur dioxide emissions equal over 10 t/km2 per year. Regrettably, present share of energy coming from renewable energy resources (RES) in Poland is less than 2.6% primary energy production (without big hydro power - above 5 MW capacity), which means ca. 105.7 PJ of energy. Nearly 98% of the renewable energy is produced of biomass. According to many experts, it is possible to increase the utilization of renewable energies by ca. 1000 PJ by 2010, which is ca. 25% of the total energy demand in Poland.

The focus of the paper will be on the Pomeranian Province, where a detailed study of biomass potential has been conducted by the Baltic Energy Conservation Agency and Heat Technology Department of Gdansk University of Technology. The territory of the Province is 18 293 km2, which puts the region eighth in Poland. The area is inhabited by about 2.2 mln people, which places it also the eight in the country. The density of population in the region is 119 persons per square kilometer. On the territory of the region there are practically no natural resources except for sands, gravel and clays. The region features significant participation of forests in its land amounting to 36%, whereas average afforestation of the

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country is about 28%. Soils of the region are rather low fertile, except for the area of Żuławy Wiślane (fen soils).

The case study under scrutiny here will dwell upon the implementation of energy policies in the Pomeranian Region of Poland and a particular focus will be on implementation of biomass and bioenergy for thermal and electrical purposes. In the course of preparation audited have been all municipalities from the region, collected have been data about most of the biomass fired plants in the Province as well as selected has been one municipalitiy for a detailed scrutiny and presentation in the paper. That municipality, namely Rzeczenica, has a biomass potential to cover its heat demand with straw only, which means that it can be regarded as a potentially 100% “green municipality”, if only its authorities will follow such strategy. In that municipality there already are some pilot projects utilizing RES, contributing in such way to increase of public awareness in favour of RES.

The Energy Law published on the 10th April 1997 obliges municipalities to plan and organize energy supply in their territories under governance. Moreover, these energy plans should incorporate the use of renewable energy sources. The domestic objective of the share of RES at the level of 7.5% in 2010 will require production of 340PJ of energy from RES (The White Paper “Energy for Future: Renewable Energy Sources” envisaged 12% participation of RES in primary energy utilization in EU). The strategy for implementation of RES in Pomeranian Region is primarily fostered by a few bodies, namely National and Regional Funds for Environmental Protection and Water Management, Ekofund and Baltic Energy Conservation Agency and Gdansk University of Technology. It can be said that most of projects in the region would not come to terms without financial support of former institutions and technical assistance provided by the latter two.

Pomeranian Region is very active in stimulation of energy plans in municipalities under governance. At the moment 80% of municipalities in the Pomeranian Region have assumptions to the energy plans completed. That places the region as a top one in the country in that respect. The assumptions of energy plans require opinion from the provincial authorities with respect to coordination of cooperation with other municipalities. Voivod checks the consistency of energy plans with the energy policy of the country as well as other legislative acts. Positive opinion is only given if the plans contain implementation of RES in the municipality and neighbouring municipalities.

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In the Programme of Environmental Protection of Pomeranian Region for the years 2003- 2006 considered is increase of utilization of renewable resources in the Region to reach 7.5% of contribution from RES in the primary energy balance by 2010.

2. ENERGY PROFILE OF THE PROVINCE

2.1. Electricity market in Region Electricity profile of the region is rather unsatisfactory as electricity is supplied from locally situated power generation units as well as purchases from the national grid (60%). Following the decline in consumption of electricity until the year 2000 ,a steady increase at the pace of 4% per annum is observed recently.

The condition of the grid and transmission and distribution devices for high voltage (400, 220, 110 kV) is satisfactory. The condition of grid and equipment for medium (15kV) and low voltage (0.4kV) lines is not satisfactory and require substantial modernization, especially in rural areas. All inhabitants of the region have access to electricity.

About 98% of produced electricity comes from combustion of coal and remaining 2% from small hydropower (professional and private ones), small wind power and biomass combustion. Major generation units in Pomeranian Region: 1. Professional CHP EC Gdańsk and EC Gdynia with total installed power of 353 MW. 2. Industrial CHPs with total power of 129 MW, Oil Refinery in Gdańsk, 3. Hydropower with total installed power of 729 MW, of which Żarnowiec pumped – storage power plant – 716 MW and small hydropower (31 professional and 18 private) with power of 29MW. 4. Wind power – 6 wind mills with total power of about 3MW. 5. Biogas CHPs on landfill sites in Gdańsk (Szadółki) and Słupsk (Bierkowo) with total power of 1 MW. 6. Gas CHP in Władysławowo supplied with gas from resources in the Baltic sea - power of 22MW. Total power installed in sources of electricity production in Pomeranian Region is 1236MW. These sources produce 3182GWh of electricity, of which: 1. Professional CHP – 1539 GWh 2. Industrial CHP – 330GWh 3. Żarnowiec hydropower plant – 1198GWh 4. Renewable resources – 114GWh

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Share of produced electricity in renewable resources in regional production of electricity is 3.6%. That number is related to the amount of electricity which is produced in the region. The number is by far above the domestic average, which amounts to about 2.7%.

2.2. Heating systems in Region

In the region there are following major producers of heat: • Gdańsk and Gdynia CHP: EC–II and EC-III, respectively, where electricity and heat are produced in combination. EC II serves to abundant part of Gdańsk and southern Sopot whereas ECIII serves to a large part of the city of Gdynia, small northern part of the city of Sopot and south part of the town of Rumia (north of Gdynia). • Two CHP sources using gas for combustion in gas turbines cooperating with electricity generators and heat recovery from exhausts, Władysławowo – gas CHP and International Paper Kwidzyn CHP, which provides heat to a significant part of the town of Kwidzyn. • Local small boilers producing only heat transmitted to the end-users in local district heating networks – such systems are in operation in about 60% of towns. • Industrial heat sources (thermal plants and CHP plants), Oil Refinery CHP in Gdańsk (150MW), Polfarma CHP in Starogard (100MW), small CHPs in sugar factories, food industry, chemical industry (5-10MW), large and medium size boilers for heat production in marine industry, food industry, local boilers for multi-family houses, public utility buildings, services and other industry. • Local boilers for multi-family houses (about 2300 units). Individual boilers for heat to one family flats and houses. It is estimated that about 135 000 of such sources is present in rural areas and about 45000 in towns.

Heat demand in 2004 was as given below: Capacity - Q ≈ 6340 MW energy - Q ≈ 79500 TJ Heating structure consumption: houses – 65%, public utility buildings – 11%, services -6%, industry – 18%. The share of energy coming from RES is about 11%. A decisive factor is combustion of waste wood in IP Kwidzyn CHP. Structure of the heating sector is rather bad as consumption is at 6% from electricity, 9% oil, 11% biomass (high consumption of waste wood in the paper factory in Kwidzyn), about 12% natural gas and about 62% coal.

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2.3. Biomass potential in Region

Pomeranian Region is characterized by high resources of solid biomass. From the existing resources there is a possibility of acquiring of energy covering the demand in the amount of about 23% of perspective heat demand in buildings and public utility sector. On the other hand growing energetic plants in the waste land enables to increase that margin almost to 100%. That number does not account for the land which can further be devoted to such plantations.

Resources of biogas energy from the sewage waste and landfills have been estimated at the level of about 121 TJ, which in reference to electricity, most often produced from such resource, corresponds to about 34 GWh.

123 3. RESULTS OF INVENTORY OF POMERANIAN REGION

Data has been collected as well as analysis has been conducted of producers and existing installations utilising biomass in Pomeranian Region. Analysis regarded two fundamental fuels, namely all kinds of straw and wood (from forests and industry).

On the territory of the Region can be found established producers of small and medium size boilers for biomass combustion. All significant installations using biomass for combustion in the Pomeranian Region have been inventoried. That means that boilers with capacities exceeding 100 kW have been inventoried. There are in the Region 36 straw and wood fired boilers with such capacities. The total installed power in such sources exceeds 33 MW. The detailed data has been presented in Table 1. In the area there are also smaller installations, with capacities not exceeding 100kW. These were not incorporated into the survey, but the number of those is quite numerous.

Boilers Fuel Installed Energy Fuel power produced use kW GJ ton Straw fired sources straw 19 150 95 750 6 839 Wood fired sources wood 14 598 86 490 7 208 Total 33 748 182 240 14 047

Table 1: Production of heat from biomass in Pomeranian Province in sources with power exceeding 100 kW.

3.1. Energy and fuel demand in the Region

On the basis of information about dwelling resources and other heated buildings the energy balance for municipalities, regions and the Province with respect to heat for heating purposes and hot water preparation have been established. The data from the recent general census has been used for that purpose. Apart from the Tricity and Słupsk the demand for heat was over 32 600 thousands GJ, which has been later compared with available resources. Conducted has been analysis of resources and utilisation of biomass in municipalities and regions and in the Region all together. Considered have been grain and

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rape straw as well as waste wood (from forests, industry, construction sites). Presented below are the findings:

Straw for heating On the basis of statistical information as well as the results of the general census for each municipality determined have been grain productions and the energy resources in grain straw. As the statistical data do not consider data for rape with reference to specific municipalities that contribution has been estimated at the level of 10% of biomass. That is a conservative estimate, as rape is becoming more and more popular amongst farmers. On the basis of determined demand for heat and energy potential in straw for each municipality determined have been indicators for heat demand for straw. That indicator proves to be highest for the Człuchów Region (31%) and Nowy Dwór Gdański Region (29%). Some of the municipalities such as Lichnowy and Przechlewo, have a potential for the entire coverage on the basis of straw. Additional potential of straw for energy purposes will come from commissioning of rape production for production of components for biofuels. Assuming that for heating purposes utilized will be 1/3 of grain straw and entire rape straw the biomass potential in the Pomeranian Province will amount to 400-700 thousands tones per annum which enables for production of 4 200 – 7 500 thousands GJ of thermal energy.

Wood for heating Analysis has been conducted based on the data from the following resources: - data about wood acquisition from the forest authorities, - data about regional afforestation and potential of increase of wooden mass. The data resources for heating purposes are rather conservative and are: - chemical (primary) energy in fuel 5 490 thousands GJ - potential of produced thermal energy 4 120 thousands GJ Consumption of wood in home fireplaces and small boilers has not been considered.

Biogas Potential biogas sources for energy purposes are following: 1. large agricultural plants, 2. waste treatment plants, 3. communal dumping sites

To date only limited amount of biogas is utilised in the following locations: landfil gas from a dumping site in Szadółki, biogas from the waste treatment plant in Słupsk and biogas from

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the pig farm in Pawłówko. Acquisition and utilisation of biogas for production of electricity and/or heat requires estimation of relevant scale of investment as well as large unit investments and reliable technology, together with automatic control of processes. That renders that it is difficult to establish the project feasibility studies, even with support of environmental funds. Landfil gas, waste treatment plants and agricultural biogas potentially can provide about 6 MWel.

3.2. Potential of energy production from biomass

The data presented below should be deemed as conservative for the Region as data does not include Tricity and Słupsk.

Resources Heat demand Coverage Wood Straw Total TJ TJ TJ TJ % 4 120 4 568 8 614 32 654 26,4%

Table 2: Possibilities for covering the demand for thermal energy in Pomeranian Province using biomass.

Presently, production of heat from biomass in Poland amount to about 144 PJ, which is about 3,5 % of available biomass potential. There is a remaining capacity of about 10MW in heating systems for implementation of biomass fired CHP, which would significantly improve the potential for production of “green energy”. In the Region there is over 10 heat and power utilities, where there is a possibility of incorporation of local biomass fires CHP as a primary source of energy. Utilisation of these capabilities will enable without any problems conformance with the goals of RES strategy in years 2010 and 2020. In calculation the possible contribution from industry has not been accounted for.

4. IMPLEMENTATIONS IN MUNICIPALITY OF RZECZENICA– PRIMARY SCHOOL, KINDERGARDEN AND ADMINISTRATION OFFICE

Let’s now focus our attention on one of the municipalities in the Region, namely Rzeczenica, where theoretically entire energy demand for heat could be covered from biomass coming mainly from straw and electricity supply could additionally have been covered from the single

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wind mill. If all these actions would be implemented then the municipality would become energy independent. Rzeczenica is located in the south west part of the Region.

Baltic Energy Conservation Agency conducted first pilot energy audits in the municipality including feasibility studies aimed at modernization of heat sources at a local school, kindergarden and administration offices. Activities were aimed at complex system modernisation of a group of buildings consisting of: - decommissioning of coal fired local boilers, - construction of a new, central heating source fired with biomass, - modernisation of internal installations, mounting of thermostatic valves. The modernisation of a boiler forms part of a strategy of conversion of all heating sources into renewable energy fuels, as the municipality has a confirmed potential in that area. BAPE conducted energy audits which enabled determination of necessary scope of works. Following modernization assembled has been a central heating boiler of power 700 kW fired with wood chips. Supplier and commissioner of a boiler was a company Kopernicus from Gdynia. Maximum moisture content in fuel should not exceed 50%.

4.2. Cost effectiveness

Investment Costs Operational costs

Investment: zł 1 040 Costs Before After 000 Fuel 59 760 16 569 Financing source Share Electricity 1 890 9 033 Other media 230 50 Provincional Fund Donation 38,5% Materials 1 000 870 for Salaries 106 400 25 460 Environmental Prot. Transport 0 19 103 and Water Overhauls 2 000 10 309 Management Loan 18,3% Ecological fees 2 000 228 Ekofundusz donation 21,2% Total cost 173 280 81 623

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5. CONCLUSIONS AND RECOMMENDATIONS

In the study presented has been the state-of-the-art on energy demand and biomass potential for energy purposes in Pomeranian Province. Despite undoubtful achievements the participation of biomass in coverage of heat demand in the Province is low. The impeding factors for the development of bioenergy sector are: • lack of monitoring and access to information on the results of pilot and demonstration objects operations, lack of information and education activities in that area, • despite prescribing by Poland of a strategy for development of renewable energy sector there are still significant legislative gaps retarding its development, • lack of programmes of development of RES and action plans in the country, only some vague proposals on the provincial, regional and municipal levels, difficulties in combination of state and private funds into for example public-private partnerships, investments into bioenergy, which are specifically very expensive, • lack of professional experience of designers who are not familiar with modern designs and technologies of systems supplied from biomass fired boilers, are not capable of relating higher investment costs for biomass fired boilers with income stemming from lower operational costs of the object.

REFERENCES

INTERREG IIIC case study, internal report of Gdańsk University of Technology

The work has been partially funded by the INTERREG IIIC Project 4E0034N Network of pioneering communities and regions working on innovative heat energy solutions – REGENERGY

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Biogas to Energy – Applications, Market Development and future Opportunities

Dr.-Ing. Frank Scholwin, Dipl.-Biotechnol. Elmar Fischer

Institute for Energy and Environment, Leipzig, Germany

Abstract

Between 1990 and 2005, in Germany the amount of biogas plants increased significantly. Today, it is estimated that there are nearly 3000 plants with an installed electrical capacity of approx. 800 MW. The sector represents approximately 50 % of the overall electrical energy produced from biomass in Germany. Additionally, the existing potentials for biogas production are very high. Compared to other options for electricity production from renewable sources of energy this potential is available with relatively low production costs. Depending on the costs of the substrates electrical energy production costs from biogas plants vary today between 0,05 and approx. 0,19 €/kWh. Regarding environmental effects biogas production and utilisation can contribute easily to the reduction of greenhouse gas emissions and thus help to fulfil the Kyoto commitments.

1 Introduction

Energy from biomass currently contributes with more than 10 % to cover the energy demand worldwide. Due to geographical, economic, and climatic differences, the share of biomass energy in relation to total consumption differs widely between different countries, ranging from less than 1 % in some industrialized countries to significantly more than 50 % in some developing countries in Africa and Asia. It is by far the most important renewable energy source, being significantly larger in energetic terms than the second largest, hydropower [1]. The existing range of technologies for the utilisation of biomass for energy production is very broad. One of the most promising technologies is the bio-chemical conversion of biomass to biogas and it’s utilization. Biogas production from organic substrates was carried out since a long time ago, but, recently, it’s utilisation grows considerably. In Germany a commercial market break through has been realised already years ago within the sewage sludge treatment in Germany. Within the last six years biogas production becomes also increasingly more important within the agricultural and food processing sector due to the Renewables Energy Act (EEG). This law guarantees a defined (high) reimbursement of green electricity feed into the public grid.

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Today, biogas is seen as a very promising option for the reduction of greenhouse gas emissions. It also offers positive effects for rural development as well as for the environ- mental sound treatment of organic waste streams and the closing of material cycles. Following the increasing amount of biogas plants being erected in Germany the technology has been dramatically improved within recent years.

2 Biogas Technology

A simple but typical configuration of a German biogas plant at an agricultural company is shown in figure 1. Within biogas plants, preparation of the feedstock (e. g. animal manure and other organic substrates) is needed that might include short-time storage, sedimentation of mineral contaminants (like sand), chopping of the feedstock into small pieces, mixing of different types of feedstock to maximize the gas yield, and heating to the needed temperature level. Then the feedstock is pumped into the biogas reactor where anaerobic fermentation takes place. For successful operation, the bacteria must always be well-mixed with the organic material. It is also important to realize a good temperature distribution within the reactor. The biogas is removed from the top of the plant and, after removal of impurities like water, stored. It is then used as a source of energy. Energy production is mainly carried out in CHP systems based on available gas enigines. The digested material is removed from the reactor and stored in a tank where a small amount of additional biogas is produced. This digested slurry is used in most cases as a valuable fertilizer, because it contains the nitrogen which has been originally within the feedstock. Due to this biogas technology helps to close the nutrient cycles within agriculture. It is therefore of increasing importance for an environmentally sound waste management.

manure

digested sludge organic waste

electric biogas energy

heat

Figure 1: Typical configuration of an agricultural biogas plant in Germany

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3 Potentials and Utilisation

In Germany, biomass contributes for covering the given energy demand with a very low extent of about 1 %. Regarding the shares of solid biomass and biogas for electricity generation, biogas utilisation from biogas plants with more than 50 % is considerable. Most important substrates for biogas production are agricultural materials (manure, bypro- ducts, material from landscape conservation and energy crops), organic material from municipalities (like sewage sludge, municipal solid waste) and organic material from the food processing industry. The potentials for these different substrates given in Germany are shown in figure 2. According to this it has to be recognised that the main potentials for biogas production and utilisation in Germany can be found in the agricultural sector.

Landfill Min Max Sewage sludge Organic MSW Other waste

Liqid manure Agricul. byproducts Landscape care Industrial org. waste Others

Energy crops 0 50 100 150 200 250 Primary Energy Potential in PJ/a Figure 2: Primary energy potential of substrates for biogas production in Germany (MSW: municipal solid waste) [2]

The development of the production of electrical energy from biogas shows a considerable increase within the last years. The number of installed biogas plants in Germany almost doubled from 850 in 1999 up to about 2 700 in late 2005 [2]. This development is shown in Figure 3.

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3000 700 2690 PlantAnlagenanzahl number gesamt 665 600 2500 InstalledAnlagenleistung electrical gesamt capacity

2010 500 2000 1760

Anlagenanzahl 1608 400 1360 Number plants of 1500 1043 300 850 Anlagenleistung in MWel 1000 247 200 190 160 500 111 100 Installed electrical capacity [MWel] 78 49 0 0

9 1 4 9 0 03 0 000 0 0 0 z 2 z 2002 z 2005 ez 2 e ez 2 e Dez 19 De D D Dez 2 D D

Figure 3: Biogas use - installed biogas plants in Germany [2]

Considering the installed capacity of biogas plants for the production of electrical energy there is a clear trend to build plants with a high installed electrical capacity. Starting in 1999 with an average electrical capacity of all German biogas plants of 53 kW today the average electrical capacity increased to about 500 kW. The overall installed electrical capacity of all biogas plants in Germany is actually about 650 MW (end 2005). The results of this investigation show that the existing biomass potentials for biogas production are only used to a fairly low extent. With decreasing investment costs due to an economy of scale and declining running costs on the one side and increased feed-in-tariffs since 2004 on the other it is to be expected that there will be a considerable increase in biogas utilisation in the next years to come.

4 Economic Analysis

Depending on the electrical capacity of biogas plants the specific investment costs decrease with increasing installed electrical capacity. Additionally within recent years the investment costs seem to be between 2 500 and 4 500 €/kW But these investment costs are depending strongly on the installed anaerobic fermentation technology as well as on the local circumstances. The investment costs result mainly from the biogas plant itself. The main cost factor is the biogas reactor itself. It is the part of the biogas plant which in most cases is constructed on site based on concrete or steel. Most of the additionally needed system components (like pumps, pipelines, aggregates) are produced off-site in large scale industry companies at

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optimised costs. They have to be connected on site. For example, the complete CHP unit, which contributes second important to the overall investment costs, is often prefabricated as weather-resistant container to be connected easily to the plant requiring only foundations on site. With an increasing size of the biogas plant the investment costs for the different system components shift as presented in Figure 4. Especially the share of the costs for planning, CHP and others decrease while the erection and material costs for the reactor increase considerably.

70 kW 500 kW Engine Others 13,0% Others Engine 8,0% 20,0% Planing 25,0% Erection 4,0% 25,0% Erection Planing 16,0% 7,0% Reactor Reactor 50,0% 32,0%

Figure 4: Overall costs of biogas plants with different capacity in Germany

Taking into account the full costs for investment of typical biogas plants in Germany the costs for the production of electrical energy can be calculated based on average economic assumptions. For small plants with an electrical capacity of about 150 kW the costs vary between 15 and 20 ct//kWh and for bigger plants with an electrical capacity of about 500 kW between 10 and 18 ct/kWh. Beneath the economy of scale the main influence on the costs comes from the costs for the substrates where energy crops play a major role in Germany.

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Table 1: Energy feed-in-tariff for biogas plants in 2004 [2]

ct / kWh Tariff composition

Basis tariff Bonus

Natural Heat Innovation biomass utilization (with CHP) Agricultural

< 150 kWel 11,5 + 6,0 + 2,0 + 2,0

< 500 kWel 9,9 + 6,0 + 2,0 + 2,0

< 5 MWel 8,9 + 4,0 + 2,0 + 2,0 > 5 MW 8,4 + 2,0 el The feed-in-tariff, guaranteed by the Renewable Energy Act in Germany (i.e. Erneuerbare- Energien-Gesetz (EEG)), is depending on the average electricity production rate of the biogas plant, the substrates used and the utilisation of an innovative technology. The different tariffs shown in table 1 result from a basis tariff, which decreases yearly with 1,5 % since 2005. Additionally a bonus for the utilisation of natural biomass (mainly energy crops, excrements) can be achieved, a bonus for the utilisation of the waste heat from the CHP plant (level depends on the share of heat used in comparison with the total available heat) and a bonus for utilisation of an innovative technology (e.g. dry fermentation, use of micro turbines, fuel cells, Stirling engines, ORC processes or upgrading the biogas to natural gas quality). Due to the feed-in-tariffs the substrate utilisation has changed very strong since 2004. A survey within the biogas plants has shown the differences (figure 5).

Substrate input (December 2004) Substrate input (December 2005)

Energy plants Organic municipal waste Energy plants Organic municipal waste

Industrial and agri- Industrial cultural and agri- residues cultural residues

Excrements Excrements

Figure 5: Substrate utilisation in German biogas plants [2]

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Especially the use of energy crops is increasingly used. But also the substrates from industries and municipalities are very interesting for biogas production and the total amount of utilisation increases, but not as intensive as the use of substrates from agriculture.

5 Future Opportunities

Energy crops are increasingly used what lead to very many innovations regarding introduction of solid substrates into biogas plants and process control of plants using high amounts of energy crops until 100 % energy crops. Thus the highest potential for biogas production – the growing of crops – can be technically used. A new path is the adaptation of new crops only for the purpose of optimised biogas production results. Here a lot of research is actually under work what will lead to crops with very high biogas yields from the agricultural area. Generally, the technology of biogas plants can be seen as state of the art with almost 3.000 plants and about 200 companies offering biogas plants and additional companies offering parts of biogas plants and services. Beneath a huge amount of small potentials for optimisation one of the biggest problems is the utilisation of the biogas what is mainly produced in agricultural companies. Here, often only electricity is produced with an efficiency of about 35 – 40 % (biogas to electricity). Other paths of utilisation offer generally better possibilities to optimize the efficiency but it is a question of political support. The following figure gives an overview on the possibilities of biogas utilization.

electricity feeding into the grid generator

gas engine heat heat production biogas biogas upgrading feedingintothe (cleaning) natural gas natural gas grid

filling station biogas fuel biogas as fuel (filling station)

Figure 6: Possibilities of utilisation of biogas

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Beneath combined use of power and heat and direct use of heat one of the most promising technologies for biogas utilisation in Germany is the upgrading to natural gas quality and the substitution of natural gas. That offers the possibilities to transport the so called “green gas” in the existing pipe system to a place with high electricity and heat demand (use at high efficiency) or to use the gas as a fuel for transportation with substitution of fossil fuels. Thus, a very flexible use of biogas is possible with a very high ecological benefit. Last not least the quality of operation and its efficiency depends very much on the knowledge of the operator. Better education leads clear to better biogas production results. A lot of German campaigns show very good results and the operator’s response is thoroughly positive. Thus a very high potential for running very good biogas plants is the increase of knowledge of biogas plant operators.

6 Conclusion

Concluding the state of biogas utilisation in Germany, biogas is a promising option for energy provision in rural areas and from industrial as well as municipal residues. This can be seen as valid for all over the world. The technology for biogas production and utilisation is available and works well. For the broad range of applications high and low tech systems are available with further development. The potentials for energy production from biogas are high and biogas can therefore contribute significantly to cover the given energy demand in Germany and probably also in other countries. The electricity generation costs are reasonable and can easily compete with other renewable sources of energy; this is probably also true for some options using fossil fuel energy. Additionally there are promising side effects, as improvement of fertiliser value not accounted for within the cost calculations in general. The environmental effects of using biogas are promising; biogas can contribute easily e.g. to the reduction of greenhouse gas emissions and thus help to fulfil the Kyoto commitments. Therefore biogas will become increasingly important in the future. This is not only true under the circumstances given in Germany. Biogas has the possibility and the potential to contribute also significantly within other energy systems like e.g. in all Baltic states. Especially promising is the fact that the biogas technology can contribute also to solve the organic waste disposal problem and to close the nutrient cycles. Additionally, the public acceptance is quite high.

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References

[1] Kaltschmitt, Martin; Smith, Kirk R.; Thrän, Daniela (2001): Renewable Energy from Biomass; in: Encyclopedia of Physical Science and Technology; Academic Press, San Diego, California, USA

[2] Institute for Energy and Environment: Monitoring zur Wirkung des Erneuerbare- Energien-Gesetzes (EEG); BMU, medium report, 2006

[3] Institute for Energy and Environment: Biogasgewinnung aus Gülle, organischen Abfällen und aus angebauter Biomasse – Eine technische, ökonomische und ökologische Analyse; DBU-Projekt 15071, final report, Leipzig, 2003

[4] Kaltschmitt, M.; Scheuermann; A.; Wilfert, R.: Biogas als regenerative Energie – Aktuelle Entwicklungen infolge von EEG und Biomasseverordnung; VDI-Tagung "Biogas – Energieträger der Zukunft", Leipzig, März 2003, Tagungsband

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Treatment of Digested Substrates for Nitrogen Removal and Emission Decrease

Dr. Ute Bauermeister*, Prof. Dr. Herbert Spindler, Dipl.Kffr. Anja Wild

GNS - Gesellschaft für Nachhaltige Stoffnutzung mbH Weinbergweg 23, D-06120 Halle/Saale, Germany

Summary The production and application of biogas is well tried. Originally, the main goal of the biogas technology was the hygienization of the strong smelling manure from live stock. With change of priorities to an energetic application of the produced biogas, an enormous increase of the digested substrates was reached, which could lead to additional emission problems by using it as fertilizer. An important aim of the agricultural policy is to reduce emissions of ammonia and other compounds of nitrogen caused by agriculture into the air and the ground water. Therefore, it is necessary to know more about technical possibilities, reduction rates and the economy of reduction technologies. In combination with the fermentation process there are new opportunities of manure treatment to reduce emissions and to avoid over-fertilization. This presentation will give an introduction to the topic and to a new technology for separation of digested substrates into low emission fertilizers, called ANAStrip®-process.

1. Emissions Caused by Agriculture In Germany about 84 % of the emissions of ammonia are emitted by stock breeding, storage and application of manure. Also important are the emissions of N2O into the air and nitrogen into water by agriculture. Table 1 gives an overview of the main emissions caused by agriculture in relationship to the sum of emissions in Germany. Similar relations can be found in most states of the European Union and the world. Therefore an important aim of the international environmental policy is to reduce emissions of ammonia and other compounds of nitrogen caused by agriculture.

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Tab. 1: Emissions in Germany [1] emissions into air (Germany, 1999)

emissions of CH4 3.271 kt/a 100 % - from agriculture 1.468 kt/a 45 %

emissions of N2O 145 kt/a 100 % - from agriculture 86 kt/a 60 %

emissions of NH3 672 kt/a 100 % - from stock breeding (stable, manure) 567 kt/a 84 % - from fertilizing (mineral fertilizer) 101 kt/a 15 %

emissions into water (Germany, 1998)

complete nitrogen (N) 755 kt/a 100 % - from agriculture 460 kt/a 60 %

In the context of the “Convention on Long-Range Transboundary Air Pollution” of the United Nations (UN), Germany has committed itself to lower the ammonia emissions to 550 kt/a up to the year 2010 (UN/ECE 1999).

The ecological effects of ammonia have to be distinguished into direct and indirect effects. The direct effects on human health, animals and vegetation are locally limited. The indirect effects are acidification and over-fertilization on the one side by conversion of ammonia into nitrate in the soil. These are supra-regional ecological effects. On the other side indirect effects are caused by conversion of ammonia into N2O, which is a supra-regional climatic effect. The following denitrification steps in the soil show the conversion of ammonia or ammonium into nitrate, nitrous oxide and nitrogen:

NH3 NO N2O N2 Luft

+ - - NH3/NH4 NO3 NO2 NO N2O N2 Boden

Nearly 60 to 90% of the N2O emissions will be released from the N-content in soil over the year while 10 to 40% of the N2O emissions will be released close to the application of nitrogen fertilizer. The greenhouse potential of N2O is 296 times higher than that of CO2 and

13 times higher than that of CH4 [2]. So by reducing emissions of ammonia the emissions of

N2O can be reduced as well.

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2. Possibilities of reducing ammonia emissions The distribution of emissions of ammonia by live stock breeding and fertilization with manure is shown in the figure 1. The emissions by storage and application of manure make up nearly 60% of the ammonia emissions.

Figure 1: Distribution of emissions of ammonia by live stock breeding [3]

36,70% 38,60% stable gaze

storage

fertilize

4,50% 20,20%

By using the biogas technology the carbon compounds of the manure will be changed into biogas and organic nitrogen will be changed into mineral nitrogen. This way, electricity and heat can be produced from biogas and the fertilizing properties of digested substrates will be improved. Table 2 shows the change of properties during the fermentation process (average values of 43 biogas plants in Thuringia).

Tab. 2: Changing of properties by fermentation [4] before fermentation after fermentation Solid substance % 11,3 5,58 carbon g/l 48,3 20,4 fatty acids g/l 7,23 0,33 nitrogen % 0,485 0,424 NH4-N % of N 44,9 63,5 pH 6,71 7,90

Because of the increasing content of NH4-N and the increasing pH-value the digested manure has a higher potential for emitting ammonia. Figure 2 shows the pH dependence of the dissociation degree and partial pressure of ammonia.

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Figure 2: Dissociation degree and partial pressure of ammonia in dependence of pH

System NH3/H2O, 20°C, NH4-N = 1,4g/l

α 1 1,6

1,4

0,8 p

1,2 NH3

0,6 1 [kPa]

0,8

0,4 0,6 0,4 0,2 0,2 0 0 pH-Wert 7 8 9 10 11 pH-value

The following possibilities of producing ammonia emissions from digested substrate exist:

Reduction in storage: Covering with straw chaff, granules, foil or concrete Reduction rate: 30 – 90 % Reduction in application: No spraying technique, e.g. injection, manure grubber Reduction rate: 30 – 90 % Reduction by removal of ammonia: Ammonia stripping, evaporation, membrane technique Reduction in storage and application: 70 – 80%

Al techniques create additional costs. The choice of a method for reducing emissions therefore depends on additional effects. The reduction of emissions by removal of ammonia from digested substrate is economical, if there are additional advantages as will be shown in the next chapters.

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3. Separation of digested substrates into low emission fertilizers by the ANAStrip®-process

GNS has developed an adapted stripping process which allows the removal of NH4-N from digested substrate by 70 to 90 %. Using this stripping process, the digested substrate is heated to 80° C max. (176 °F) and under a slight negative pressure a recycle gas is produced, leaving the strip reactor ammonia-enriched. The ammonia-enriched recycle gas then streams through an ammonia reactor where the ammonia reacts in an aqueous solution containing an absorbing substance which generates ammonium sulfate.

The sum equation is:

2 NH3 + CO2 + H2O + CaSO4 = CaCO3 + (NH4)2SO4 (1)

The mineral products are: • Fertilizer-solution of ammonium sulfate (35 to 40 weight-%) • Solid fertilizer of calcium carbonate (70% dry substance)

The main advantages of the ANAStrip®-process are: • No use of aggressive chemicals for stripping o No consumption of sodium hydroxide or other alkalis for stripping ammonia. o No neutralization of manure by chemicals after the stripping is necessary.

• Generation of ammonium sulfate with the competitively priced gypsum o Direct generation of ammonium sulfate from outgoing ammonia is possible, without generation of concentrated ammonia solution as an intermediate step. o No partial plant for extraction of concentrated ammonia solution necessary. o No consumption of expensive and aggressive sulfuric acid for production of the ammonium sulfate fertilizer. o Gypsum from the flue gas desulfurization is economical in price and easy in storage.

So this process combines low operating costs while avoiding hazards to personnel and the environment.

The first small demonstration plant was build in 2003 by GNS in cooperation with the agricultural company Barnstädt and the scientific assistance by FÖST e.V., promoted by

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Saxony-Anhalt and the EU (figure 3). The demonstration plant is run with 250 l digested substrate with about 5 g/l NH4-N. From that, in the ammonia reactor with 6 kg REA-gypsum suspended in water about 3,9 kg ammonium sulfate (TS) and 3,4 kg lime (TS) are generated. In the residue digested substrate 1 g/l NH4-N remain at an adjusted strip degree of 80% (results reported in [5].

Figure 3: Demonstration plant for separation fertilizers from digested substrate

For commercial realization we have a planning and licence partner, the SSM – Technology. The options for the ANAStrip®- process are:

Basic ANAStrip®- process Separation of Ammonium-Nitrogen (NH4-N) from substrates and production of ammonium sulfate fertilizer solution and calcium carbonate fertilizer (solid) ANAStrip®- Plus – process In addition to the basic ANAStrip®- process, soluble phosphates in the substrate are transformed into insoluble calcium phosphate, which can be separated during the dewatering The application fields of the ANAStrip®- process are: • avoiding emissions of ammonia • reduction of the digested manure application area

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• production of mineral fertilizer from manure and organic residues • adapted management of N-fertilizing to the local conditions • prevention of a nitrogen inhibition in the digester Ö use of digested substrate as dilution water Ö use of substrates with high N content or high content of solid (renewable substances, chicken dung) Ö accelerate biogas production

The different applications lead to different technical solutions in using the ANAStrip®- process. Figure 4 shows a biogas plant with chicken dung and utilization of digested substrate as dilution water after separating fertilizer.

Figure 4: Using digested substrate as dilution water after separating fertilizer

CHICKEN RECEIVING DIGESTION STORAGE LIQUID FIELD MANURE DIGESTATE APPLICATION

THERMAL POWER ANASTRIP (NH4)2 SO4 (l) 2 SEPARATE CaCO (s) ELECTRICITY PROCESS 3 FERTILIZER

FIELD PRESS CAKE APPLICATION PRESS DEWATERIN with COMPOST WATER G PHOSPHATE FERTILIZER

DRYING FERTILIZER CONCENTRATE

4. Cost efficiency of the ANAStrip®- process An example of a normal biogas plant in combination with the ANAStrip®-process is given in the following layout:

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Layout of biogas plant: Layout of ANAStrip-plant:

Substrate: cattle manure 12.000 t/a Content of NH -N: 4,97 g/l 4 pig manure 14.000 t/a Strip efficiency: 80 %

chicken dung 3.200 t/a N removal: 124 t/a

corn silage 3.500 t/a Consumption REA-Gips: 801 t/a

sum 32.700 t/a Mineral fertilizer products:

Digested substrate: (NH4) SO (40%) 1.200 m3/a 2 4 Content of NH -N: 4,97 g/l CaCO3 (dry): 442 t/a 4 Energy consumption:

Energy yield 10.007 MWh/a Electricity: max. 14 kW

Exhaust Heat: max. 551 kW Electricity (η = 40%) 500 kW with heat recovery < 325 kW Heat (η = 45%) 563 kW

The costs for the treatment of digested manure with the ANAStrip®-process in this example are about 5 €/m³. In comparison with other methods of manure treatment this is less expensive and in a similar range. Figure 5 shows a comparison of the ANAStrip®-process with other methods of manure treatment. Today, the capital costs of the ANAStrip®-process for small plants are still high, but with growing plant size and experience in planning and running the investment costs will decrease, so that the main advantage of the new technology - the very low variable running costs - will become more important.

There are various economic advantages for the agricultural companies. As a result of the ANAStrip®-process a storable fertilizer and compost is produced. This can be used for own fertilizing tasks or can be sold. By removing the nitrogen, a better usage of the nutrient potential of manure is possible. This way, costs for mineral fertilizer can be saved. By fertilizing with the nitrogen enriched liquid, costs for transportation and application area can be saved as well. In Germany the Renewable Energy Act (EEG) promotes the use of produced exhaust heat from the CHP. For consumption of heat energy by the ANAStrip®- process an amount of 2 ct/kWh can be reached. In the given example the benefits are between 3 and 6,5 €/m³, so in an average case the costs are reduced to 1 €/m³.

In comparison with other methods of emission control in storage and application of manure or digested substrate, with costs between 1 and 4 €/m³, the ANAStrip®-process can already be economically used for the case of the given example.

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Figure 5: Comparison with other processes of manure treatment (examples) 14,00

12,00

10,00

8,00

€/m³ 6,00

4,00

2,00

0,00 10.000 31.143 199.800 351.000 21.000 18.000 24000 36.000 21.124 21.124

m³/a m³/a m³/a m³/a m³/a m³/a m³/a m³/a m³/a m³/a

ANAStrip® air steam membrane techniques evaporation stripping stripping

capital costs fix running costs variable running costs

The criteria for a preferred and economical utilization of the ANAStrip®-process are: • High content of nitrogen in the substrate (like chicken dung) • Size of plant > 80.000 t/a • Agricultural companies with surplus of N-fertilizer • Agricultural companies with transport distance for application > 5 km • Agricultural companies with only stock breeding without cultivation areas • Biogas concepts using digested substrate as dilution water

If one or more of criteria are met, the running costs can be over compensated by benefits.

References [1] Daten zur Umwelt 2000; Umweltbundesamt (Hg.), Erich-Schmidt-Verlag, Berlin, 2001 [2] PPC: Climate Change 2001. The scientific basis; Eds: J. T. Houghton, Y. Ding, J. Giggs et. al; Cabridge University Press [3] KTBL-Schrift 406: Emissionen aus der Tierhaltung; KTBL-Schriften-Vertrieb im Landwirtschaftsverlag GmbH, Münster, 2002 [4] Reinhold, G., Eigenschaften und Einsatz der Gärreste in der Pflanzenproduktion; Vortrag zum KONARO-Fachgespräch am 26.10.05 an der LLG in Bernburg

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FÖST e.V. (Hg.): Ganzheitliche Maßnahmen zur Güllebehandlung; Schriftenreihe Ökologische Stoffverwertung 1/20

Author Information Dr. Ute Bauermeister*, GNS - Gesellschaft für Nachhaltige Stoffnutzung mbH Weinbergweg 23, D-06120 Halle/Saale, Germany phone: +049 345 5583-754, fax: +049 345 5583-706 e-mail: [email protected], www.GNS-Halle.de

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THE POTENTIAL OF PRODUCTION AND USE OF LIQUID BIOFUELS IN LATVIA

Mg.sc.ing. Ruslans Smigins Motor Vehicle Institute, Latvia University of Agriculture, Jelgava, Latvia

Abstract The paper presents the analysis of the possibilities to produce and use liquid motor biofuels in Latvia. It also summarizes the main results of the study on the introduction of biofuels in motor vehicles and the identification of policy measures in support of the promotion of liquid biofuels in accordance with the Directive 2003/30/EC and the further policy measures for developing biofuels in Latvia.

Introduction Latvia, as many countries, has a high dependence on imported fossil energy resources. During the last years the consumption of fossil fuels increased very rapidly. In 2005 the consumption of diesel fuel was 630 thousand t/a, and the use of gasoline 320 thousand t/a [8]. The dependence of fossil fuels in country increasing and the best possible way of reducing it in future, could be a successful development of biofuels in internal market of country. Development and use of liquid biofuels for transportation in Latvia began to move in 2004 after the Republic of Latvia had joined European Union. Important stimulus there was also the Law on Biofuels, which was accepted by the government in April 2005, and which outlines measures necessary to ensure that by December 31 (2006) biofuels will constitute not less than 2.75% of the total share of fuel for transport in the national economy, and not less than 5.75% by December 31 (2010). The Directive 2003/30/EC of the European Parliament and the Council was also an important stimulus to promote the “Biofuels program” of Latvia, the main aim of which is strengthening the agricultural sector and lowering the dependence of the state on imported petroleum fuels.

Resources for biofuel production Latvia is a small country (62 thous. km2) with sufficient high area of agricultural land (38.5 % of total area) and forests (45.0 %) and there no exist important limitation for intensive farming. Unfortunately the usage of set-a-side lands are not so high as it would be necessary. For example, arable land in 2001 was 1.8 million ha, from which the sown area of crop cultures was 420 thousand ha. In comparison with 1990, when the sown area was 675 thousand ha it has diminished by 255 thousand ha or by 38%. Therefore biofuel

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development could create a great chance for energetic crop cultivation in the future. As in many countries, also in Latvia conditions the most important resource for production of renewable motor fuels could be grain for bioethanol and rapeseed for biodiesel. To ensure biofuels not less than 2.75% of the total share of fuel for transportation by December 31 (2006), 29 thousand tons of biofuels are needed, including 13 thousand tons of bioethanol and 16 thousand tons of biodiesel. To produce these quantities of biofuel in 2006, it is necessary to produce 47 thousand tons of corn and 46 thousand tons of rapeseed [1]. Rapeseed in Latvia is a new corn culture and the farmers are still learning its cultivating technology. Due to this reason the yields of rapeseed are not stable and the average yield is not high – 1.9 t (2004) per ha. It is influenced also by the weather conditions and by the lack of corn drying kilns. Latvia is located in the temperate climate zone and in general the climatic and soil conditions are suitable for rapeseed cultivation. With the improving of the rapeseed cultivating technology and with building the drying kilns in the needed amount, helping to reduce the loses of rapeseed, by the opinion of experts the average yields of rape will stabilize in the level approximately 2.5 tons per ha and production of rape will exceed 450 thousand tons per year [2]. During the last years sown areas of rapeseed have increased almost 10 times (see Figure 1). This is connected with the developing biofuel industry and also with the possibility to export rapeseed to other European countries.

80 160 70 Area 140 60 Production 120 50 100 40 80 30 60 20 40 Area (thousand ha)

10 20 Production (thousand t) 0 0 2000 2001 2002 2003 2004 2005 Years (2000-2004)

Figure 1: Sown areas and production of rapeseed (2000-2005)

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Production of biofuels Biodiesel At present in Latvia there are only a few small scale (with capacity 2.5-5.0 thousand tons annually) biodiesel plants in operation, and some large plants are planned to build in the nearest years (see Table 1). The first biodiesel plant in Latvia and in all the Baltic States was built by private resources by the company “DELTA RIGA” Ltd. in Naukseni (Valmiera district) with capacity 2.5 thousand tons of biodiesel annually. It is in operation since November 2001 and has produced during the last three years about 7.5 thousand tons of biodiesel. In the year 2005 the plant in Naukseni does not work on full capacity. The reconstruction of the plant is planned with the goal to double the production capacity up to 5.0 thousand tons annually. At present, company plan also to build another biodiesel production plant “DELTA JELGAVA” (Jelgava district) with capacity 50.0 thousand tons of biodiesel annually. In 2004 another biodiesel plant was built by the company “Mezrozite” Ltd. (Jelgava district) with the capacity 5.0 thousand tons of biodiesel annually. At the end of year 2005 another company “Mamas-D” Ltd. started to operate with the capacity 3.0 thousand tons annually. A large biodiesel plant “BioVenta” (Ventspils) is under construction with the planned capacity 100.0 thousand tons of biodiesel annually. Starting of the plant is planned at the end of the next year [2]. Another private company “EcoDiesel” Ltd. with participation of the farmers cooperative “LatRaps” is planning to build another large biodiesel plant with capacity 100.0 thous. t/a. This plant is planned to start at the end of 2007. Operation of these plants will be a large stimulus to cultivate the neglected arable lands and to rise the production of rapeseed as the raw material for biodiesel production. Some plans for biodiesel production have also companies which produce vegetable oil. Very important precondition for profitable production of biodiesel is also utilization of its by-product – glycerine. At present, this is a problem for all biodiesel producers in Latvia. There are different reasons, which prohibit increase of biodiesel production. The main reason of this is absence of facilities for cleaning and drying of rapeseeds which does not allow the large part of farmers to produce rapeseeds. To overcome this situation, the Union of Fuel Sellers and Producers (DTRS) and the Latvian Association of Biofuels Producers (LBA) have worked out the project for developing the regional models for biofuel production to be called Biocentres. According to this project in the next two to three years in different regions of Latvia there will be build 20-25 such Biocentres, but in ten year period the amount of them will reach 50-75, evenly distributed over the territory of Latvia. Each such centre will cover the farmers’ houses by the circle with the radius approximately 30 km [3].

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Table 1: The existing and planned biofuel plants in Latvia (2006) [3]

The title of company Type Raw Produced Projected The year of materials, in output, of biofuel thous. t/a 2004/05, thous. t/a starting thous. t/a

1. “Delta Riga” Ltd. BioD 2.5 7.5 4.6 2001

2. “Mezrozite” Ltd. BioD 5.0 15.0 0.3 2005

3. “Mamas-D” Ltd. BioD 3.0 9.0 0.5 2005

4. “Eco Diesel” Ltd. BioD 100.0 250.0 0 2007

5. “BioVenta” Ltd. BioD 100.0 300.0 0 2006

6. “BIO-DIZELIS” Ltd. BioD 3.5 10.0 0 2007

7. “Delta Jelgava” Ltd. BioD 50.0 150.0 0 2008

“Jaunpagasts Plus” BioE 28.0 8. 10.0 1.8 2004 Ltd.

9. “Lako” Ltd. BioE 4.0 12.0 0 2006

Explanations: BioD – biodiesel; BioE - bioethanol

It is planned that such Biocentre could include three groups of farmers. For the first group could belong farmers who only do growing and harvesting of rape. Transporting rapeseeds just from field to Biocentre may be done by farmer himself or by transport means from Biocentre, which collects the rapeseeds from farmers and from its own plantations. The second group includes farmers, who have technical background area for cleaning and drying rapeseeds by themselves. They transport ready prepared rapeseeds directly to the storage silos of the Biocentre. The third group of farmers have cleaning and drying machines and also some storage facilities and they can deliver rapeseeds directly to the pressing plant of Biocentre in relation to a precise plan of supplying. The similar Biocentre models is planned to use also for bioethanol production from grain and sugar beets.

Bioethanol Bioethanol production in Latvia is under development. The spirit producing company “Jaunpagasts Plus” in 2004 opened a new production unit especially for bioethanol

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production in Iecava (Bauska district) with a projected output 10.0 thousand tons of bioethanol annually. At present, bioethanol production in Latvia is carried out only at this plant. In the 2004-2005 1.8 thousand tons of bioethanol were produced in this production unit. Another bioethanol plant with the planned capacity 4.0 thousand tons annually is under construction in Kalsnava (Madona district).

The use of liquid biofuels At present, there is not intensive use of liquid biofuels in transport system of Latvia neither in private, nor in public sectors. Only some private companies and a part of some vehicle owners have chosen to use biodiesel in their vehicles. In that case important reason is fuel price, which is only some 4.8% lower for biodiesel compared to fossil diesel (0.587 LVL or 0.838 Euro). Such difference in price is not attractive for costumers. Other important reason, which also prevent intensive usage of biofuels is insufficient information system. A large part of people does not have any information on biofuel quality, sustainability, impact on engines and the environment. In that case there is necessary to create a biofuel quality control system, which would inform customers in fueling stations that the fuel which they will use will not damage their cars. It would be useful to organize an agency under the Ministry of Agriculture, which could give consultations to potential biofuel users and coordinate biofuel development [2]. The first test with biodiesel was carried out in Riga in one of the city bus lines in year 2002. After 6 months operating the test was stopped, and the engine was removed from the bus for further investigations. The results showed that a quite old bus engine can operate with pure biodiesel without problems. In total the consumption of biodiesel was not large for the year 2005 and constituted only 0.35% or 2.89 thous. tons compared to conventional diesel fuel consumption [5]. Consumption of gasoline mixed with 4.5-5% of bioethanol for the last year constituted only 14.82 thous. tons compared for non-mixed gasoline – 335.0 thous. tons [5]. Recently the interest in vehicles, which can be operated with pure cold pressed vegetable oil has also increased. In the last years a few farmer’s cooperatives and farmers which produce rapeseed oil themselves began to modify conventional diesel engines, adapting its fueling system for use of rapeseed oil as fuel. Special conversion kits, including additional fuel tank for rapeseed oil and its heating device, were made and mounted on the vehicle. This system mainly is used on high power transport vehicles, tractors and combines. For example, oil producer “Iecavnieks” Ltd (Bauska district) adopted almost 50% of engines of its motor vehicle fleet for rapeseed oil use. At present, vegetable oil use as motor fuel is not regulated therefore vehicle owners can use it without problems. Two year experience of the use of

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pure rape oil as fuel showed that engines had not any problems if the operating instructions were considered. It gives about 40% on fuel expenses in case that rapeseed oil is produced on the spot at the cooperative or farm [3].

Policies and measures for liquid biofuel promotion In comparison with fossil fuel sector, which was established a long time ago, biofuel sector is quite new in Latvia, and can not compete with the fossil fuels. During the last year a lot of new things were done for biofuel promotion, but there still exist a number of different barriers, which prevent valuable biofuel introduction in the market. One of the most important barriers could be economical barriers, which are connected with different economical stimulation forms (loans, subsidizing, setting free of taxes etc.). The future development of biofuel production and utilization requires a substantial support from the government to each player in the chain from the rapeseed to the biofuel. Production and use of biofuels can be developed only if it gives each player the profit. In this field of activities the government has exceeded the time and the market situation is still insufficient. As mentioned previously, one of the most important measures done according to biofuel introduction in Latvia is the Law on Biofuels, which was accepted by the Saeima on April 1, 2005 [6]. The Law outlines measures necessary to ensure that by December 31 (2005) biofuels will constitute not less than 2% of the total share of fuel for transport in the national economy, and not less than 5.75% by December 31 (2010). In cooperation with non government organizations a action plan on the implementation of the Law of Biofuels was developed and accepted by the Cabinet of Ministers on June 22 (2005) for each task specifieing the responsible ministry and the time schedule. According to these regulations biodiesel and bioethanol are reduced rate of excise tax in the volume in which the corresponding biofuel is added to the fossil fuel (diesel or gasoline). In order to promote in Latvia the use of biodiesel fuels acquired entirely from rapeseed oil, and the production and use of biofuel blends with fossil diesel, a reduced excise rate has been enforced in the Law “On Excise Duties”. If the fossil diesel is blended with biodiesel made from rapeseeds, than the excise tax is decreased: 9 For blends containing 5-30% vol. of rape biodiesel; 9 For blends containing 30% vol. and more of rape biodiesel; 9 For biodiesel produced in full volume from rapeseeds the excise tax is zero. In order to promote the use of bioethanol the excise tax is decreased also for petrol, containing 4.5-5.0% bioethanol or 10-12% ETBE, if the bioethanol is obtained from agricultural raw materials, is dehydrated and denaturated.

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There was given also a direct subsidation to the biofuel producers in the year 2005 in the limits which are determinated by the production quotas. In year 2005 the direct support to producers was as follows [5]: 9 170 LVL (243 Euro) for 1000 liters of biodiesel for quotas 12.5 million liters; 9 140 LVL (200 Euro) for 1000 liters of bioethanol for quotas 11.4 million liters. To ensure compliance with the requirements of the Directive 2003/30/EC, the necessary normative acts had been adopted in year 2005 regarding requirements for biofuel quality, conformity assessment, market supervision and procedures for consumer notification [5]. Significant step in promotion of the production and consumption of liquid biofuels were also special studies, according to the quality of biodiesel during storage, which were conducted by Ministry of Economic Affairs of Latvia and ”Potential, opportunities and obstacles of biofuels in relation of the implementation of Directive 2003/30/EC in Latvia” – conducted by Latvian Environment Protection Fund [5]. The last one study are especially important because it reveal possible liquid biofuel introduction scenarious in Latvia, identifieing potential biofuel users and evaluating environmental effect of liquid biofuel usage in transport according to each scenario. There could be different possible ways for faster introduction of biofuels in the road and off the road transport sector of Latvia, which could be worked out on the basis of the analysis of experience of some foreign countries into introduction of biofuels. One of the ways could be involving the government initiative to provide economical, legislative and informative measures for influence on the feedstock producers, biofuel producers, biofuel distributors and sellers in such a degree that the selling price of biofuel in the filling stations will be lower than the petroleum fuel price. It could be especially suitable for marketing biodiesel, because biodiesel can be sold as pure fuel or as biodiesel and fossil diesel blends in every proportion [3]. The other way could be introduction of low blends (up to 5% vol.) of biofuels with petroleum fuels [3]. In such situation filling stations, which are marketing the fuels containing not more than 5% of biofuel admixture need not install additional fuel tanks and pumps, associated with the labeling obligations. Thereby it is easy without additional expenses to start the biofuel market. There exists also possibility to not embrace no one of the mentioned situations, but produce and deliver in different periods different quantities and concentration of biofuel blends. In total it could be variant how to better control the amount of sold biofuel in any definite year to meet the requirements of the EC Directive 2003/30/EC. This situation is more flexible because it allows to the producers and deliverers to operate more widely depending on the seasonal disposition of the feedstock production.

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The use of pure biofuels in public transport or municipal transport could be also a very good example, especially, for public.

Conclusions The potential of liquid biofuels production in Latvia is large and the production and use of them is going to increase rapidly. The production of biofuels now is stimulated by some important policy incentives and in future it certainly will increase. At present, biofuel usage stimulation process is started and it is to be expected that it will be better than now. To facilitate the expansion of biofuels in the transport sector, it is recommended to introduce some scenarios in the fuel market and give public information on biofuel quality, sustainability and impact on engines and environment.

References 1. Program “Production and use of biofuels in Latvia” (2003-2010), (2003), Riga, Ministry of Agriculture. (in Latvian). 2. Gulbis V., Shmigins R. Biofuels in Latvia – present state and future perspectives. (2005) // Proceedings of 14th European Biomass Conference and Exibition: ”Biomass for Energy, Industry and Climate Protection”, France, Paris, October 17-21, 2005, 1079–1082. 3. Gulbis V, Smigins R. Development of biofuels in the transport sector of Latvia. (2006) // Proceedings of International Scientific Conference “World Bioenergy 2006”, Sweden, Jönköping, May 29 – June 1, 2006, 115–120. 4. Official Journal of the Republic of Latvia. (2005) Nr. 52. 5. Report pursuant to Article 4(1) of Directive 2003/30/EC of the European Parliament and of the Council of 8 May 2003 (URL: ec.europa.eu/energy/res/legislation/doc/biofuels/member_states/2006_rapports/2003 _30_lv_report_en.pdf) 6. Agricultural farms of Latvia 2005: collection of statistical data, Riga, (2006) 36. 7. Agricultural farms of Latvia 2004: collection of statistical data, Riga, (2005) 36. 8. Energy balance in 2004. (2005) Central Statistical Bureau of Latvia, Riga, (2005) 86. 9. Agricultural and rural area of Latvia, Riga (2005) 142.

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Cultivation of Cereals for Starch and Bio-Ethanol Production in Saxony-Anhalt

Dr. agr. Lothar Boese State Research Center of Agriculture, Forestry, and Horticulture Saxony-Anhalt, Center of Agronomy, Bernburg, Germany

Summary

The capacity for ethanol production in Germany has strongly increased in the last few years. In addition to more than 1,000 old small agricultural and commercial distilleries with an output of 220,000 m³ there were built up three big factories and a rather small one with a capacity of 600,000 m³/a. The new plants produce ethanol exclusively for fuel or fuel additives. Input material are cereal grains, preferably wheat, rye, and triticale. The demand of the new plants for grain amounts to more than 1.5 million tons per year. Further plants are in stage of construction or planning.

The grain for ethanol production in general should be well, usual in trade, and free of pests, chemicals for conservation, and mycotoxins. Well-formed kernels and a high starch concentration in the grain are desired. Particularly suitable are high-yielding varieties of good agronomic features, high level in resistance against deseases, and of low grain protein concentration. Agronomic practices should be adjusted to a healthy crop, which produces high grain yield and grain quality, focussed on high starch concentration in the grain. Special attention has to be paid to nitrogen fertilization. Moderate rates of fertilizers should be applied in order to reach high grain yield and high grain starch concentration, as show field trials in Saxony-Anhalt. First nitrogen rate in early spring should be emphasized. Late rates in stage of shoo-ting or heading have to be rejected.

Introduction The capacity for ethanol production in Germany has strongly increased in the last few years. In addition to more than 1,000 old small agricultural and commercial distilleries with an output of 220,000 m³ in 2003 [1] there were built up three big factories and a rather small one with a capacity of 600,000 m³/a in all. The plant in Zörbig (federal state Saxony-Anhalt, capacity 100,000 m³/a) has started its production in 2004, the plants in Zeitz (Saxony-Anhalt, 260,000 m³/a) and Schwedt (Brandenburg, 230,000 m³/a) started in 2005. While the traditional distilleries produce alcohol for drinking or pharmaceutical industries, the new plants only produce it as fuel or fuel additive for Otto engins. Input material at the mentioned plants are cereal grains, preferably wheat, rye or triticale. The demand for grain amounts to more than 1.5 million tons per year. According to the obligation by law of adding bio-ethanol

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to fossil petrol, the demand for ethanol as a biofuel will be increasing in Germany. Further plants, which are in stage of construction or planning, will use sugar beet as well. The whole capacity of planned ethanol production from new plants in Germany will be about 1.9 million m³/a in future, inclu-ding 1.6 million m³/a in graín processing distilleries. They need roughly 2.5 tons of grain to produce one cubic meter ethanol. Therefore the demand of graín of all new plants, already producing or in stage of planning as well, will be about 4.0 million t/a.

Requirements to the input material

The aim of ethanol production from the economical point of view is a high ethanol output per ton grain input. Prerequisite for this is a high starch content within the grain. Therefore in some contracts the price of grain for ethanol production is coupled with the starch content of the grain. Producing grain for ethanol distillation, the farmer should be interested in a high grain yield and a high starch concentration in the grain too. Results from field trials have shown, that starch concentration in the grain is strongly negatively correlated with the concentration of crude protein. Therefore the farmer has to focus all agronomical measures, in particular nitrogen fertilization, on high grain yield and – in the other way round than for bread wheat – on low concentration of crude protein and high concentration of starch. Additionally, well-formed kernels (1000-kernel-weight, hectolitre weight) and high ethanol productivity of the grain are wanted.

Table 1 shows the requirements of the Zörbig and Schwedt ethanol production companies in grain quality. In general, the grain must be well, usual in trade and free of pests, chemicals for conservation, and mycotoxins. Conservation additives would hamper or stop the microbial process of alcoholic fermentation. The indicated limit values for mycotoxins are to be observed absolutely because the distiller’s grains with solubles (DGS) as a by-product are used as feedstuff for animal nutrition.

Choosing species and varieties

Bio-ethanol can be produced theoretically from all plants or parts of plants, which contain carbohydrates, such as sugar, starch or cellulose. Because of technological and economical reasons the interest in Germany is currently focussed on the cereal species wheat, triticale, and rye. Barley seems not to be convenient because of lower starch content in the grain. The maize producing area for grain in Germany is rather marginal because of climatic disfavour.

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There is a positive correlation between grain starch content and ethanol productivity of the grain (Fig. 1). Both features depend on species and variety, furthermore on site and season of cultivation. Varieties of rye – because of pentosans in the grain – have a starch content mostly 3...8 % below those of wheat and triticale varieties.

Table 1: Quality Requirements of Grain for Ethanol Production in Saxony-Anhalt

1.1.1 Feature Rye Wheat (MBE Zörbig) (Südzucker AG Zeitz) Moisture (%) <15.0 <16.0 Hectolitre weight (kg/hl) >68 Starch content (% in o.m.) >58.0 Crude protein content (% in d.m.) >11.0 Falling number (s) >175 Black dockage (%) <1.0 <1.0 Little and Broken Kernels (%) <20 Ergot bodies (Claviceps purpurea) (%) <0.1 Mycotoxins: Deoxynivalenol (DON) (mg/kg) <1.0 <0.5 Zearalenon (ZEA) (mg/kg) <0.05 <0.05 Ochratoxin A (mg/kg) <0.05

Ethanol productivity (l/dt grain dry matter) 47 Winter wheat 46 Winter rye Winter triticale 45

44

43

42

41 62 64 66 68 70 72 74 Starch content (% in grain dry matter)

Figure 1: Ethanol productivity of wheat, rye and triticale grain depending on starch concentration (after ROSENBERGER 2005 [2]; samples of 2003 and 2004 season)

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On average, the ethanol productivity of rye is also a bit lower than those of wheat or triticale grain. However, deciding for one or the other species for ethanol production, the farmer in general has to look at first at the different efficiency of cereal production at his own site, further at sales opportunities and prices.

Choosing suitable varieties for ethanol production the farmer has to focus on general characters, but also on some special features. In general he should prefer high-yielding varieties of good agronomic properties such as high frost resistance, resistance against lodging, pests and diseases. Resistances against ergot (Claviceps purpurea) and Fusarium species are of special importance in this connection because distiller’s grain as a by-product is used for feedstuff, as mentioned above. An important special feature for ethanol varieties should be a high starch concentration. As a rule, the starch content in the grain is more or less negatively correlated with the crude protein content (Fig. 2). Varieties with low crude protein content show a high starch content, and vice versa. A low falling number as a negative variety feature in baking cereals should not be a problem here, because, processing grain to ethanol, the first step is the conversion of starch to sugar.

Grain starch concentration (% in dry matter) 66 Variety Avanti Rasant

65

Picasso

Fernando 64 Recrut Nikita

63 9,5 10,0 10,5 11,0 11,5 Grain crude protein concentration (% in dry matter)

Figure 2: Starch concentration in the grain of six winter rye varieties depending on crude protein content at Bernburg site in 2005 season

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In Saxony-Anhalt and other federal states of Germany additionally to the common variety testing trials in cereals special trials in winter wheat were carried out to select convenient varieties for ethanol production. In this trials with a special nitrogen fertilization regime, the starch concentration in the grain samples has been analysed. As a result from these trials in general the new highest-yielding varieties with low protein content are recommended for ethanol production. They realize in general the highest starch yield per hectar. These are new varieties of the B quality group (bread wheat) or C group (remaining varieties). Group A varieties (quality wheat) are only exceptionally suitable if they show a low crude protein content. In winter rye and winter triticale also new high-yielding varieties with good agronomic features are adviced. The range of starch concentration at rye and triticale varieties is not so extended as in winter wheat.

Cropping practices

Crop rotation: The general recommendations for crop rotation should be applied also in the case of grain production for ethanol. However, legume crops like peas, beans, lupins, alfalfa, clover, and other as preceeding crops should be avoided because of uncontrolled delivery of inorganic nitrogen from crop residues in the soil during growing season. The higher inorganic soil nitrogen level would push up the grain protein concentration and decrease the starch concentration at the same time.

Sowing: In order to get a high grain yield, sowing of winter cereals on favoured sites in Saxony-Anhalt should be realised from September 20 until Oktober 10. On poor sandy soils sowing should be done one or two weeks earlier. On average, a sowing rate of 300 germinable kernels per square meter is suitable. In the case of hybrid varieties the sowing rate should be reduced to 100...200 kernels per square meter because of its high seed prices.

Crop protection: Choosing varieties with high resistance against lodging or the application of growth regulators in the case of lodging risks, respectively, should be part of a well-practiced cereal production. It defends from losing grain yield and grain quality by lodging and is a prerequisite of an effective harvest. Field-specific controlling of weed, pests and diseases according to economically based infestation thresholds ensures the yield formation process and also the required quality of the products. In particular the farmer has to watch infections of fusarium during flowering stage because of the above mentioned problems with mycotoxins. The threshold values of mycotoxin concentration in the grain are to be observed absolutely.

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Fertilization: Basic fertilization (P, K, Mg, Ca) should be done in the same manner as in the case of cereal crops in general. The same principles should also be applied to sulphur and micronutrients (Cu, Mn, Zn, Mo, B). Application of organic fertilizers like manure, slurry or compost has to be renounced. The expected inorganic N delivery from the organic matter in the case of applying organic fertilizers should unnessesarily enhance the N concentration and reduce the starch concentration in the grain.

Groundwork of the nitrogen fertilizer assessment should be the specific algorithms and computer based calculations of the crop nitrogen requirement. In Saxony-Anhalt the computer programm “Nitrogen requirement assessment” is generally accepted. It calculates on the basis of field-specific information, such as soil type, crop, preceeding crop, inorganic soil nitrogen concentration and other, the first nitrogen rate in early spring and the second rate four weeks later at the beginning of shooting. To re-adjust the second (shooting) nitrogen rate to the course of nitrogen uptake it is possible to use crop testing methods, for example rapid nitrate test or YARA N-Tester. The second rate should be applied not to late, latest at the onset of shooting. First and second rate as a whole, nitrogen supply should be sufficient for a side-specific high grain yield. In order not to enhance the grain protein content, applying a third nitrogen rate – the so-called quality rate or ear rate – should absolutely be renounced.

Results of nitrogen fertilization field trials

In Saxony-Anhalt several field experiments were carried out in order to test nitrogen fertilization in its influence on grain yield and grain quality of cereals. Results from a trial series with winter rye (variety Picasso) on a loamy-sandy soil at Gadegast side in the 2003 to 2006 seasons will be shown here. In this trial series nitrogen fertilization (as calcium ammonium nitrate) has been varied in total amount and partitioning, respectively. On average of four years, the highest grain yield of 84 or 85 dt/ha was obtained with a total nitrogen amount of at least 120 kg/ha N (Fig. 3). Compared with this, the reduction of nitrogen amount by 40 kg/ha N led to a grain yield drop of 3 dt/ha. There is a slight tendency on the level of 120 kg/ha N to strengthen the grain yield by stressing the first nitrogen rate in early spring.

The crude protein concentration in the grain depends on the total amount of nitrogen fertilization (Fig. 4). The partitioning of fertilizer, however, also influences the protein concentration. Displacing a part of the total fertilizer amount to a later stage of crop development, to the stage of shooting or heading, enhances the protein concentration

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remarkably. On the contrary, highest starch concentration in the grain is reached at low or zero nitrogen level (Fig. 5). To get a high starch content under normal cropping conditions, the major part of N fertili- zer should be applied early in the spring. Finally, the starch yield, as the product of grain yield and starch concentration, is of major interest. It reaches a high value on a relatively low

Grain yield (dt/ha) 90 85 80 75 70 65 60 55 0 N 80 N 120 N 160 N 50 1 th rate (March): 0 40 40 40 80 120 80 2 nd rate (st. 30 ): 0 40 40 80 40 0 40 3 rd rate (st. 37) : 0 0 40 0 0 0 40 Partitioning of fertilizer N (kg/ha N)

Figure 3: Grain yield of winter rye depending on total amount and partitioning of mineral nitrogen fertilizer (average 2003-06)

Grain crude protein concentration (% in dry matter) 13

12

11

10

9

0 N 80 N 120 N 160 N 8 1th rate (March): 0 40 40 40 80 120 80 2nd rate (st. 30 ): 0 40 40 80 40 0 40 3rd rate (st. 37) : 0 0 40 0 0 0 40 Partitioning of fertilizer N (kg/ha N)

Figure 4: Grain crude protein concentration of winter rye depending on total amount and partitioning of mineral nitrogen fertilizer (average 2003-05)

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nitrogen level of 80 kg/ha (Fig. 6). Applying more nitrogen, the starch yield is increasing only marginally. Highest values will be reached, stressing the first application rate in early spring. To get further information for advising the farmers, the new research project “Cultivation of cereals for ethanol production / Feeding with distiller’s grains with solubles” has started in 2004.

Grain starch concentration (% in dry matter) 66

65

64

63

0 N 80 N 120 N 160 N 62 1th rate (March): 0 40 40 40 80 120 80 2nd rate (st. 30 ): 0 40 40 80 40 0 40 3rd rate (st. 37) : 0 0 40 0 0 0 40 Partitioning of fertilizer N (kg/ha N)

Figure 5: Grain starch concentration of winter rye depending on total amount and partitioning of mineral nitrogen fertilizer (average 2004-05) Grain starch yield (dt/ha) 55

50

45

40

35

0 N 80 N 120 N 160 N 30 1th rate (March): 0 40 40 40 80 120 80 2nd rate (st. 30 ): 0 40 40 80 40 0 40 3rd rate (st. 37) : 0 0 40 0 0 0 40 Partitioning of fertilizer N (kg/ha N) Figure 6: Grain starch yield of winter rye depending on total amount and partitioning of mineral nitrogen fertilizer (average 2004-05)

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Cooperating several federal states in Germany, in this project, among others, coordinated field trials on several sites will be carried out with winter wheat, winter rye, and winter triticale to select the most suitable varieties and suitable patterns of nitrogen fertilization.

References

[1] Wetter, Ch.; Brügging, E.: Frischer Treibstoff – selbst gebrannt, Bauernzeitung 26, pp. 32-33, 2005

[2] Rosenberger, A.: personal information, 2005

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OVERVIEW AND OPPORTUNITIES OF BIODIESEL PRODUCTION IN KALININGRAD REGION

Aizenberg Genady (Director), Tsipukhovskiy Andrey * Kaliningrad State Land-Reclamation Center, Kaliningrad, Russia

Two or three years ago activity targeted to biodiesel production would have been pointless because of the low home market price for the diesel fuel derived from oil. However, in recent years constant rising of the oil price in the world market as well as in the home market forced us to pay attention to alternative ways.

Analysis and prognosis of the whole situation in the chain: "growing rape – rapeseed oil extraction – biodiesel production – selling of biodiesel", showed the following results: ƒ positive factors 9 presence of huge land areas that could be used for expanding of rape planting area and planting areas of other plants with good oil content; 9 there is an experience in growing rape in Kaliningrad region and some other regions of the Russian Federation; 9 cost-effective ratio between the diesel fuel price in the world and home markets and the rape growing expenses; 9 friendly tax policy toward farmers; 9 low charges for transport service and electricity. ƒ negative factors 9 no experience in biodiesel production and using of it as a vehicle fuel in Russia; 9 not sufficient tech. level of rape producers that prevents them from expansion of the planting areas; 9 expensive and complicated situation with bank loans and investment resources.

The analysis of the raw material market. Rape is being grown in Kaliningrad region on the land area about 20000 hectares. Average rapeseed productivity is about 2.5 t/hectare, and gross sales volume – 50000 t/year. Rapeseeds grown in Kaliningrad region satisfy European quality requirements and whole harvest is exported abroad. The purchasing price for rapeseeds in 2006 was about 240-250 Euro/t, at the same time growing expenses are not higher than 90-110 Euro/t.

Favorable weather and climate conditions, presence of vacant planting areas and high profitability of growing rape would be a good motivation for increasing production volume in

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the future. At the same time, constant rising of the production expenses (first of all vehicle fuel price, its share is up to 60-70% of total expenses) will drop down profitability in the near future and force farmers to look for other ways for reducing production costs and focusing on alternative vehicle fuel.

The prognosis of the overall biodiesel production expenses in case of "from growing field to fuel station". Nowadays prices are considered. ƒ 0.35 EUR/kg if growing, oil extraction and conversion take place in Kaliningrad region; ƒ 0.32 EUR/kg if growing and oil extraction take place in other regions of Russia and oil to biodiesel conversion in Kaliningrad region, including transport charges.

At present time in Russia wholesale price for traditional diesel fuel equals to 0.47 EUR/kg. At the same time wholesale price for biodiesel in European countries is at level of 0.7 EUR/kg.

According to analysis results, requirements in biodiesel production facilities can be spitted in three different scales:

ƒ 8000-10000 t/year – for processing of the rapeseed oil delivered from other regions; ƒ 2 t/day – to meet the needs of the local farming industry; ƒ 0.5 t/day – for using in small farming companies.

BIODIESEL PRODUCTION PLANNING

Short-term goals are:

ƒ attracting attention of rape producers, Russian and foreign investors and authorities to economical and ecological benefits of biodiesel production in Russia; ƒ establishing of the business contacts with foreign manufacturers of agricultural and processing equipment, investors, leasing companies in order to rise tech level, get investment resources and train Russian specialists.

Medium-term goals are:

ƒ establishing of the holding company mainly based on foreign investments that will consolidate: 9 re-established farming companies based on reallocated and bought lands and leased equipment; 9 newly established oil extraction companies in regions of rape cultivation;

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9 biodiesel production companies (mainly in Kaliningrad region); 9 trade companies (on initial stage selling biodiesel to European countries, until biodiesel market will be created, and then, as prices in home and world markets will tend to be equal and adaptation of Russian consumers will take place, selling it in the Russian market).

Such organizational plan has its benefits. It can lower to minimum risk of raw material deficit in case of bad weather condition (planting areas located in different regions). For Russian and foreign investors it gives possibility to fully control financial and economic activity of the holding company (transparent money management). And finally, that arrangement is free from many troubles that Russian farming companies suffer from nowadays.

At medium-term stage pilot holding company establishment is planned. Based in Kaliningrad region and having production volume about 8000-10000 t/year it would be an excellent showcase, training facility and the example of " the live state of the art technology", that definitely will be helpful in further technology promotion in Russia.

Long-term goals are:

ƒ increasing of base holding company activity and reaching production output level of 250000 t/year.

At the present time we have the following business contacts interested in biodiesel project realization:

ƒ Ministry of agriculture and fishery in Kaliningrad region; ƒ a number of European manufactures, producing biodiesel conversion units, oil extraction equipment and agricultural machineries; ƒ farming companies in Kaliningrad, Belgorod and Stavropol regions which grow rape; ƒ companies-wholesalers of diesel fuel; ƒ National Auto-Motor Institute (NAMI, Moscow, Russia).

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Energetic Utilization of Common Reed for Combined Heat and Power Generation

Dr. Mirko Barz *(1), Prof. Dr. Matthias Ahlhaus (1) , Dr. Wendelin Wichtmann (2) (1) Laboratory for Integrated Energy Systems, Stralsund University of Applied Sciences, Germany (2) Institute for Sustainable Development of Landscapes, Greifswald, Germany

Abstract Among other biomass fuels, common reed is considered as a promising source for Bioenergy. Initiated by the Institute for Sustainable Development of Landscapes of the Greifswald University partners from science, industry and agriculture decided to develop an integrated process for the energetic utilization of common reed from rewetted peatlands for combined heat and Power generation (Project ENIM). This paper will present the results of the first orientating combustion examinations and point out a possible commercial utilization opportunity for the combined generation of heat and power in an existing biomass CHP plant.

1 Introduction The strong increase of the worldwide energy demand, the predominant use of fossil sources and the known related consequences for the environment (e. g. acid rain, GHG emissions and global warming) and for national economies (e.g. dependency from energy source imports, increasing prices, competition between national economies to get the energy resources etc.) require a structural change of the fossil source based energy economies towards to a sustainable energy economy. Increasing the share of renewable energy in the energy balance enhances sustainability and biomass is one of the most important renewable energy sources in the Baltic Sea Region. In Germany for example the biomass demand for energetic utilization (supported by governmental regulations like the renewable energy law) is increasing enormously. We recognise a raise of the prices and particulate regional shortages of biomass supply. On the other hand the renewable energy act created conditions for a lucrative use of biomass in co-generation power plants, so the biomass demand will continuously increase in the near future. Beside the classical biomass fuels such as e.g. wood new biomass sources must be made available to avoid bottle necks. Common reed (Phragmites australis) is such a promising biomass source. But concerning an environment friendly utilization there still exist a considerable demand for research and development, caused by the difference in chemical composition, physical properties and

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partially due to their critical characteristic reaction behaviour as a solid fuel in relation to the classical solid biomass feedstock wood.

2 Potentials Common reed is a perennial and fast growing plant. The data to the biomass yield varies strongly in dependence of the cultivation location (3,6 – 43 t/ha [1]). Ikonen indicated for the North European Region (Finland and Estonia) 3 – 15 t/ha dry biomass [2]. In the North- German lowlands where nearly 20 percent of the agricultural areas are more or less degraded fens often more than 15 t · ha−1 dry matter can be produced. About 200,000 hectares of lowlands could be rewetted for biomass production (see Fig. 1) in Northern Germany the harvest from these areas could feed 20 power plants of 20 MW capacity each if yields of about 10 t/ha are assumed [3].

Fig 1: Suggestion for a sustainable land use of fens. Profile cross-section of a fen after restoration [4]

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3 Characterization of common reed as fuel Biomass feedstock’s distinguish between each other in a wide range and also exhibit a great difference towards solid fossil fuel. The essential difference is expressed by the heating value (LHV) and the elementary composition of the feedstock. The results of the proximate- and ultimate-analysis of common reed are presented in Table 1 in which for comparison also values for other potential biomass fuels and fossil fuels are illustrated. feedstock LHV volatile ash ultimate analysis (mf) in in % in % in % MJ/kg C H N O S Cl fossil fuels hard coal 31,8 38,8 6,3 79,4 5,1 1,5 6,6 1,0 <0,2 brown coal 27,0 55,0 7,6 68,4 5,5 1,8 15,4 1,3 - biomass fuels common reed 1) 17,7 66,8 8,8 46,5 5,9 0,3 42,5 0,14 0,16 miscanthus 17,8 81,0 2,7 47,26,5 0,7 41,70,13 0,23 pine wood 18,7 84,0 0,3 50,9 6,6 0,2 42,0 0,02 0,01 wheat straw 17,1 79,6 5,3 46,7 6,3 0,4 41,2 0,1 0,4 grain straw 17,5 80,1 4,6 47,0 6,2 0,4 41,7 0,1 0,34 maize straw 16,8 - 5,3 45,6 6,4 0,3 43,3 0,04 0,16 rape straw 17,0 78,7 6,5 48,3 6,3 0,7 38,0 0,2 - Table 1: Comparison of fuel analysis for biomass samples and fossil fuels [5], 1) [6]

The LHV of common reed is significant lower than the heating value for fossil fuels and requires higher fuel inputs for the same energetic output (which is generally valid for all solid biomass fuels). However, compared to other biomass fuels the relative high value of LHV = 17,7 MJ/kg indicates that reed is an promising energy source. The nitrogen content is very low so that no problems concerning nitrogen oxide emissions were expected (for biomass combustion processes only the formation of NOx from fuel nitrogen is important, the formation of thermal NO occurs only at high temperatures to a great extent and plays during biomass combustion a minor role). Compared to pine wood the higher contents of chloride, sulphur and ash might cause problems regarding emissions and process management if the reed is used conventional combustion technologies. Sulphur and chlorine are air-polluting relevant elements. During combustion these elements mainly convert to SOx and HCl. Especially the chloride content could increase the risk of Cl-corrosion.

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4 Orientating small scale combustion examinations in a 50 kW boiler The aim of the small scale combustion examination was to convert the chemical energy of the reed (indicated by the LHV) into thermal energy of the flue gas as complete as possible to minimise any losses. Furthermore the ecological operation of the combustion technology is the most important criteria for the evaluation in order to keep within the emission limits. A

Biomass Boiler, Typ “SOLARFOCUS therminator” with a capacity of 50 kWth was used for the combustion experiments (see Fig. 2). This boiler is part of the biomass combustion test facilities at the Laboratory for Integrated Energy Systems and after modifications applicable for different biomass fuels like firewood, briquettes, pellets and wood chips.

Fig. 2: Biomass Boiler, Typ “SOLARFOCUS therminator”

The reed was used in form of small bales (see Fig. 3) and reed chaff (see Fig. 4).

Fig. 3: Small reed bales Fig. 4: Reed chaff

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The results of the first orientating examinations in the small scale application indicated that common reed can be used as biogenious fuel. Tab. 2 shows the results of the exhaust gas analysis.

Flue gas component Average value Maximum value CO 220 ppm 321 ppm NO 200 ppm 263 ppm O2 9 Vol% 7 Vol% CO2 11,5 Vol% 13,4 Vol% Tab. 3: Results of the exhaust gas analysis – common reed combustion [6]

Sulfure oxide emissions couldn't be measured. The used reed was harvested in March 2005 (in Hungary) so that the potassium content of the fuel is already low. Examinations of the ash melting behaviour showed that the ash melting point (which is directly related to the potassium content in the biomass fuel) is above 1420 °C. No ash slagging was recognized in the combustion chamber. Because of the rigid structure of the blades of reed and the high ash content of nearly 9 % the ash can block the fixed grate of the furnace and thus interfere the air supply and the exchange of the reaction products. It was necessary to riddle the fire bed each 15 minutes to ensure a continuous operation the test facility.

Fig. 5: Fire bed during reed chaff combustion

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An unwanted effect of riddling the fire bed is that considerable amounts of unburned reed have been moved to the ash chamber. Figure 6 illustrate the different ash fractions found in the ash chamber.

Fig. 6: fine and coarse ash fraction after reed combustion

Especially the coarse ash fraction contains a considerable amount of unburned carbon (see Tab. 4).

Fine ash fraction Coarse ash fraction Share of the fraction in % 89,1 10,9 Carbon content in % 1,0 53,11 Tab. 4: Carbon content in the ash fractions

The resulting low total fuel utilization of only 93,3 % doesn’t satisfy the requirements of an environment friendly combustion (convert the chemical energy as complete as possible into thermal energy) and optimization measures are required.

5 Conception for commercial reed utilization To be able to estimate the possibility of a commercial use of reed as energy source small scale examinations are insufficient. Furthermore, the combined generation of heat and power is of particular interest, caused by economic conditions defined in the German Renewable Energy law (fixed price electricity purchase for electricity generated from renewable sources). Operators of Biomass CHP plants evince a great interest to make new biomass sources available. Within the framework of the cooperation project “ENIM”, the industrial partner (GMK - Gesellschaft für Motoren und Kraftanlagen mbH) will provide a

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power plant for large scale combustion examinations. Development, planning, construction and operation of power plants are the main business fields of GMK and they have set up more than 20 biomass CHP plants, among these the first biomass power station with ORC- cycle technology in Mecklenburg Vorpommern which one will be used for the commercial tests runs. Since 2001 this power plant (see Fig. 7) is in operation and wood chips are used as fuel for the combined heat and power generation.

Fig. 7: ORC-cycle biomass power plant in Friedland, planned, constructed and operated by GMK

Examinations for the commercial utilization of common reed will proceed under commercial conditions. For this purpose the reed will be used at first in various mixtures with wood chips. If procurable the share of reed will be raised in relation to wood chips to the point off 100 % reed utilization. The agricultural partners of the ENIM project will ensure the fuel supply with common reed during the test runs and for further operation of the power plant.

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References [1] Timmermann, T. 2003: „Nutzungsmöglichkeiten der Röhrichte und Riede nährstoffreicher Moore Mecklenburg-Vorpommerns“, Greifswalder Geographische Arbeiten 31: 31 - 42. [2] Ikonen, I. : “Common reed as source of Energy”, UBC Bulletin 1/2006 [3] Wichtmann, W.: “Biomass for energy from rewetted peatlands”, Proceedings of the 2nd International Baltic Bioenergy Conference, Stralsund, Nov. 2 – 4, 2006 [4] Wichtmann, W; Timmermann, T.: Restoration of fen peatlands with industrial plants. Poster on the Millenium Wetland Event, Quebec, Canada, 2000. Program with Abstracts p. 488 [5] Barz, M.: “Zur Thermischen Nutzung von Biomasse“, Mensch & Buch Verlag, Berlin 2001, ISBN 3-89820-217-8 [6] Lange, T.: „Orientierende Versuche zum Einsatz von Getreide und halmgutartiger Biomasse in einer Kleinfeuerungsanlage“, Diplomarbeit, FH Stralsund 2006

175 Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

Yield of woody biomass from southern Norway and their suitability for combustion and gasification purposes depending on the harvest frequency

M.Sc., Dipl.-Wirtsch.-Ing.(FH), Martin Kunze(1), Prof. Dr. Henrik Kofoed Nielsen* (2), Prof. Dr.–Ing., Matthias Ahlhaus (3)

(1) Offenburg University of Applied Sciences, Offenburg, Germany (2) Associate Agder University College, Grimstad, Norway (3) Stralsund University of Applied Science, Stralsund, Germany

1 Introduction The intention of the project is to analyse the influence of the harvest frequency on the yield of the woody biomass and their suitability for gasification and combustion purposes. In 2002 an area of 1,250 m² has been cultivated with three different clones of willow ('Christina' Salix viminalis, 'Aage' and 'Steffan' Salix schwerinii x Salix viminalis) and three clones of poplar ('Spirit' and 'Muhle Larsen' Populus trichocarpa as well as 'O.P.42' Populus trichocarpa x Populus maximoviczii). In case of the willow parts of the field were harvested at the beginning of 2003 and 2004. In April 2005 an additional area of 250 m² with three willow clones was established ('Gudrun' Salix dasyclados, 'Tordis' (Salix schwerinii x Salix viminalis) x Salix viminalis and 'Aage' Salix schwerinii x Salix viminalis) with 150 cuttings each. Table 1 gives an overview of the different woody energy crops established in Grimstad.

Table1: Overview of the different woody energy crops established in Grimstad, stand April 2006 Block number Clone Genus Age of the shoots Age of the roots [#] [-] [-] [a] [a] 1 Gudrun Willow 1 1 2 Tordis Willow 1 1 3 Aage Willow 1 1 4 Christina Willow 2 4 5 Aage Willow 2 4 6 Steffan Willow 2 4 7 Christina Willow 3 4 8 Aage Willow 3 4 9 Steffan Willow 3 4 10 Christina Willow 4 4 11 Aage Willow 4 4 12 Steffan Willow 4 4 13 O.P. 42 Poplar 4 4 14 Muhle Larsen Poplar 4 4 15 Spirit Poplar 4 4

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2 Materials and Methods In each willow block two central rows were harvested to measure the yield. To measure the water content samples were dried in laboratory ovens at 105°C until constant weight. The poplar blocks 13 to 15 merely contain 30 trees. Only half of them were harvested in order to follow the production after two more (six in all) years. Bow saw, lopper and hand pruner were used for harvesting the mentioned trees. The remaining border plants were harvested by a chain saw.

The combustion experiments were carried out at the University of Applied Sciences in Stralsund with the boiler “therminator” (Solarfocus, Austria). Different four year old samples from Norway were burned as wood chips and as wood logs. The CO content in the exhaust gas was measured with a portable exhaust gas analyser “IM 2800” (IM Environmental Equipment Germany GmbH).

The gasification experiments were performed at the University of Applied Sciences in Offenburg with a downdraft gasification unit. The produced gas was burned in an old Renault 4 Otto engine which is connected to an asynchronous machine. The amount of generated electricity was measured with an electrical counter. The composition of the produced synthesis gas was determined continuously with an ABB “Advance Optima” gas analysis system.

3 Results and Discussion 3.1 Yield Based on the harvest in late winter 2006 alone you could evaluate the growth as Figure 1 shows. Here you see that 'Aage' and 'Steffan' reach their maximum annual yield after a growing time of only two years. In 'Aage' up to 16 tDM/(ha a) could be harvested. The yield in 'Christina' is rather poor. The maximum value is obtained after the third growing year with

14.2 tDM/(ha a).

The standardised yields of the old willow seam to decrease with an increasing growing time. Especially in ‘Steffan’ it is clearly visible that a high harvest frequency leads to optimal yields.

The breeders of the newer willow clones also recommend to harvest after a growing time of two to three years. [1]

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18 16 14 /(ha a)]

DM 12 10 8 6 4 2 Standardised yield [t 0 Christina Aage Steffan Clone 2 Years 3 Years 4 Years

Figure 1: Comparison of the standardised yields of the different clones in the old willow depending on the harvest frequency

With the results of the harvests in 2003 and 2004 it is possible to follow the development of the yield of the different willow clones since the establishment in 2002. This correlation is demonstrated in Table 2 and Figure 2.

Table 2: Absolute measured yields during the harvests in 2003, 2004 and 2006 in the old willow Block Clone Harvest frequency 2002 - 2004 2004 - 2006 Sum Sum

[#] [-] [-] [tDM/ha] [tDM/ha] [tDM/ha] [tDM/(ha a)] 4 Christina 7,90 18,20 26,10 6,53 5 Aage2+2 13,90 32,00 45,90 11,48 6 Steffan 18,00 28,64 46,64 11,66 - 2002 - 2003 2003 - 2006 - - 7 Christina 4,22 42,86 47,08 11,77 8 Aage1+3 3,10 32,82 35,92 8,98 9 Steffan 1,34 35,28 36,62 9,16 ---2002 - 2006 10 Christina35,29 35,29 8,82 11 Aage4 50,85 50,85 12,71 12 Steffan35,74 35,74 8,94

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60

50 /ha]

DM 40

30

20

Absolute yield [t 10

0 Christina Aage Steffan Clone 1 Year 2 Years 4 Years

Figure 2: Accumulated absolute yields of the different clones in the old willow measured in 2003, 2004 and 2006. The yield after four years undisturbed growth divided into measured yield after the first and second year.

The yield of the one year old shoots from the field established in 2005 ranges from

1.2 tDM/(ha a) in 'Aage' and 2.9 tDM/(ha a) in 'Tordis'. Compared to the field of 2002 this area has not been fertilised before establishment. So the yields are rather poor according to the yields measured in 2003 in the old willow. 'Tordis' and 'Gudrun' are the most promising clones in the new willow field as they nearly reach the yield of 'Aage' measured in 2003 without fertilizer. This agrees with the findings of the company delivering the cuttings “Ny Vraa”/Denmark. [2]

Regarding the four year old poplar the yield varies from 7.1 tDM/(ha a) in 'O.P. 42' to

10.29 tDM/(ha a) in 'Spirit'. This is based on a single row free from competition on one side. The harvest of the remaining trees in the beginning of 2008 will show how the annual yield will develop perhaps with a more ideal growing time of six years for poplar.

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3.2 Combustion experiments The combustion experiments were performed with the “therminator” boiler at University of Applied Sciences in Stralsund. This boiler has a nominal thermal power of 50 kW and is suitable for wood logs, wood chips and pellets. It is designed as a shaft furnace. The experiments were done with samples of the four year old willow clones 'Christina', 'Aage' and 'Steffan' as well as a mix of the poplar clones 'Spirit' and 'Muhle Larsen' (both Populus trichocarpa). The four different wood types were combusted as wood logs and as wood chips i.e. eight experiments in all.

It was found that the power of the boiler is generally higher when it is operated in the wood log mode. In average the difference is 14.9 %. This fact is illustrated in Figure 3.

50 45

] 40 th 35 30 25 20 15

Boiler output [kW 10 5 0 Christina Aage Steffan Poplar mix Kind of wood

Wood chip operation mode Wood log operation mode

Figure 3: Average output of the boiler in kWth depending on the kind of wood and the operation mode of the boiler in a stationary operation point

The average thermal power in the wood chip operation mode in case of 'Christina' and the Poplar mix is rather poor. This is due to a bad wood chip quality particularly with regard to excess lengths and higher impurities of the fuel. The highest thermal power reached 'Aage' and 'Steffan' in the wood chip operation mode with 46.8 kWth and 46.2 kWth respectively. Furthermore it was found that the released power of the boiler was more constant during the wood log operation mode. Independently of the kind of wood the thermal power always

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varied a lot more in the wood chip operation mode. A reason for this phenomenon is the batch wise fuel feed during the wood chip operation mode. In the wood log operation mode the whole fuel had been added before the combustion was started. Normally stoker augers give a more continuous feeding compared batch stoking. The boiler originally was designed for wood logs. So this is why a more constant power release was achieved with wood logs. Figure 4 demonstrates this fact for the willow clone 'Steffan'.

70

60 ] th 50

40

30

20 Boiler output [kW 10

0 0 4 8 1216202428323640444852 Duration of combustion [min] Wood chip operation mode Wood log operation mode

Figure 4: Variation of the thermal power of the boiler in wood chip and wood log operation mode during the combustion at a “stationary operation point”

The CO content in the exhaust gas is a measure for the quality of the combustion. Low CO contents describe an almost complete combustion. The German legislation allows a CO content of 4,000 ppm at a thermal power of 50 kW. [3] The measuring range of the instrument is between 0 and 2,000 ppm. The CO content in the wood chip operation mode is always higher than in the wood log operation mode as it can be seen in Table 3. In case of the Poplar mix the CO content reached values higher than 2,000 ppm which were no more measurable with the equipment available.

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Table 3: CO content in the exhaust gas in ppm depending on the kind of wood and on the operation mode of the boiler in a stationary working point Clone Wood chip operation mode Wood log operation mode [-] [ppm] [ppm] Christina 651 82 Aage 431 124 Steffan 309 230 Poplar Mix >2000 234

3.3 Gasification experiments The gasification unit at University of Applied Sciences in Offenburg is designed as a downdraft gasifier. It was filled with approximately 20 kg of wood pieces with a maximum length of six centimetres. So it could be ensured that the material slips down the shaft. In the first experiment the water content of the material which was harvested three months before was 24.6 %. This was too high and caused many problems, especially with condensate and tar in the system. The temperature in the reaction zone was not high enough so that the synthesis gas producing reaction didn’t start. The quality of the gas was so poor that the engine didn’t start. Hereupon the remaining samples were dried at 65°C for two days to a water content of five to nine percent. With this water contents the experiments ran satisfactorily. The measured data during the gasification experiments are listed in Table 4 and Table 5. There are no data for block five because of the aborted experiment with the high water content mentioned above. In block one and three there was not enough material available for gasification experiments. All experiments were carried out with material harvested between March and April 2006.

Table 4: Determination of the wood consumption during the gasification experiments Block Duration of the experiment Wet material Water content Dry material Wood consumption

[#] [h] [kg] [%] [kgDM][kgDM/h] 2 1.83 14.0 7.02 13.02 7.10 4 1.50 12.4 7.89 11.42 7.61 6 0.33 2.8 7.79 2.58 7.75 7 1.50 12.6 7.96 11.60 7.73 8 1.50 12.4 7.52 11.47 7.65 9 1.50 13.4 6.01 12.59 8.40 10 1.50 12.6 8.79 11.49 7.66 11 1.50 13.6 8.13 12.49 8.33 12 1.50 13.0 9.08 11.82 7.88 13 1.50 11.4 6.75 10.63 7.09 14 1.33 11.0 5.76 10.37 7.77 15 1.50 13.0 6.82 12.11 8.08

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Table 5: Determination of the specific produced electric power per block

Block Produced electric power Specific produced electric power

[#] [kWh] [kWh/kgDM] 29.060.70 46.810.60 61.650.64 77.450.64 87.200.63 96.450.51 10 7.26 0.63 11 6.20 0.50 12 6.55 0.55 13 6.18 0.58 14 5.20 0.50 15 6.36 0.53

In Figure 5 the results of the old willow are illustrated. The value for 'Aage' – 2 years is missing due to the abortive experiment.

0,7

0,6

0,5 ] DM

electric power 0,4

0,3 [kWh/kg 0,2

0,1

Specific produced 0,0 Christina Aage Steffan Clone

2 Years 3 Years 4 Years

Figure 5: Comparison of the specific produced electric power of the different clones in the old willow depending on the harvest frequency

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Interestingly the highest specific produced electric power was generated with the one year old shoots of 'Tordis'. There is no correlation between the age/kind of wood and the specific produced electric power observable. In fact the specific produced electric power seams to be more depending on the way the system is operated (volume flow of the gasification air, pressure in the system). Within the system it is not possible to keep these parameters constant during every experiment.

Figure 6 shows the composition of the produced synthesis gas during a stationary operation point depending on the water content of the gasification material. It is obvious with a low methane content in the producer gas, that a high content of carbon monoxide always goes along with a low content of carbon dioxide and the other way around because the amount of carbon in the fuel is limited. The values of methane and hydrogen seam to be stable over the water contents tested. With slightly higher water contents more hydrogen could be generated.

25

20

15

[Vol.%] 10

5

Composition of the synthesis gas gas Composition of the synthesis 0 5 5,5 6 6,5 7 7,5 8 8,5 9 Water content of the gasification material [%]

Methane Hydrogen Carbon dioxide Carbon monoxide

Figure 6: Composition of the produced synthesis gas during a stationary operation point depending on the water content of the gasification material

Compared to literature the values of carbon monoxide are rather low, the values of carbon dioxide in this case are quite high. The values of methane and hydrogen on the other side agree with other findings. [4]

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4 Conclusions

The highest yield of 16 tDM/(ha a) could be found for the willow clone 'Aage' with a growing time of just two years. 'Steffan' also reaches its highest yield after two years while 'Christina' achieves the maximum standardised yield after three years of growing. The new willow clones 'Tordis' and 'Gudrun' are most promising and should reach even higher yields in future. The yields measured in the poplar are lower than the maximum yields of the different willow clones.

Based on the few experiments in Stralsund, for combustion purposes it’s recommended to use wood logs. They deliver a higher thermal power than wood chips. The released thermal power in the wood log operation mode is much more even than in the wood chip operation mode due to the batch-wise fuel addition. Wood logs are stoked in a single batch though wood chips are stoked in many batches Using wood logs the CO content in the exhaust gas is lower which is an indicator for a higher combustion quality.

For gasification purposes low water contents are required. There is no correlation between the specific produced electric power and the age/kind of the wood. In fact the way of operating the system seams to influence the amount of generated electricity. The synthesis gas consists in average of 21 % carbon monoxide, 15 % hydrogen, 11 % carbon monoxide and 1,4 % methane.

References

[1] Agrobränsle AB, 70117 Örebro, Sweden. www.agrobraensle.se [2] Ny Vraa Bioenergi I/S, 9382 Tylstrup, Denmark. www.nyvraa.dk [3] 1. BImSchV § 6 [4] Hans Hartmann, Arno Strehler: Die Stellung der Biomasse im Vergleich zu anderen erneuerbaren Energieträgern aus ökologischer, ökonomischer und technischer Sicht. Münster: Landwirtschaftsverlag, pp 61 – 65, 1995

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Towards an ecologically sustainable energy production based on forest biomass – Forest fertilization with nutrient rich organic waste matter

Kenneth Sahlén *(1), Nina Åkerback (2) (1)Swedish University of Agricultural Sciences, Faculty of Forest Sciences, Department of Silviculture, 90183 Umeå, Sweden (2) Svenska yrkeshögskolan – University of Applied Sciences R&D, Energy and Environmental Engineering Fin 65201 Vasa, Finland

This project is an EU-financed collaboration between Swedish University of Agricultural Sciences, Faculty of Forest Sciences in Umeå, Sweden, Svenska yrkeshögskolan - University of Applied Sciences in Vasa, Finland and the Finnish Forest Research Institute in Kannus Finland.

Today there are pronounced goals within the EU that aim towards an ecologically sustainable community, and there is also a global goal to decrease net carbon dioxide emissions. These goals have resulted in efforts to increase the use of renewable biofuel as energy source. This will result in an enlarged demand for biomass for energy production. To meet this demand, the forest resources in the Nordic countries will be used to a far greater extent in the future. One way to meet this increased tree biomass demand is to increase forest tree growth through supply of nutrients, of which nitrogen is the most important.

Organic nutrient rich waste matter from the society might be used as forest fertilizer. This would result in increased supply of renewable tree biomass, decreased net carbon dioxide emissions, increased forest ecosystem carbon sequestration, decreased methane emissions from sewage sludge landfill and decreased society costs for sludge landfill or incineration. Nitrogen is the most limiting factor for tree growth of the boreal conifers and considerably increased growth is generally achieved after application of N-containing fertilisers. An increased use of municipal sewage nutrients and compost of mink and fox manure for forest fertilization would contribute to a society development towards increased ecological sustainability. Therefore, the purpose of this project is to develop methods for forest fertilization with municipal wastewater, sludge and manure from mink and fox farms.

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The project may be divided into three main parts. The first part is the chemical composition of the fertilizer, where the main objective is to increase the nitrogen content in sludge-based fertilizers and in compost of mink and fox manure.

The second part involves the technique and logistics for forest fertilization. The idea is to develop equipment that may be integrated in existing forest technical systems.

The third part consists of field fertilization investigations, in which environmental and tree growth effects of nutrient substrate type and application quantity are determined. A number of field fertilization experiments are established in Scots pine forests in Sweden and Finland. The results from the field experiments so far show that tree growth may be increased by 30- 70% after fertilization with sewage nutrients after 3-5 years. The content of heavy metals in berries and mushrooms as well as the nitrate concentration in the soil water, are not elevated after fertilization.

Author Information Kenneth Sahlén Swedish University of Agricultural Sciences, Faculty of Forest Sciences, Department of Silviculture, 90183 Umeå, Sweden Phone: +46 70 655 3633 E-mail: [email protected]

Nina Åkerback Svenska yrkeshögskolan – University of Applied Sciences R&D, Energy and Environmental Engineering P.O.Box 6, Fin 65201 Vasa, Finland Phone: +358 6 328 5721 E-mail: [email protected]

187 Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

Mixed cropping systems for fermentation gas production on sandy soils

Matthias Dietze State Research Centre of Agriculture and Fishery Mecklenburg-Vorpommern, Institute of Field-, Plant- and Horticulture, 18276 Gülzow, Germany

Mixed cropping systems mean the simultaneous cultivation of different crops and/or sorts of plant species on one field. Up to the middle of nineteenth century, mixed cropping systems had a great importance.

A stronger support on organic farming in agriculture in the last decade led to a “rediscovery“ of mixed cropping systems because the renouncement of synthetic fertilizers and chemical plant protection can be compensated by this cultivation system within certain limits. The re-establishment of mixed cropping systems with grain crops, for example false flax/peas and false flax/barley, particularly proved in recent time in organic farming systems in Bavaria and Austria was successful.

Apart from the increase of the diversity of species and higher yield stability the substantial advantages of the cultivation of crop combinations are the following: • more flexible habitat adjustment, • better weed suppression, • reduction of the disease infestation, • lower expansion of parasits, • simultaneous food and non-food production, • production of qualitatively supplementing biomasses.

In order to make use of the advantages of mixed cropping systems, a applicability of the simultaneous cultivated plants should be given, for example that they complement each other in the requirements of habitat, that a simultaneous sowing is possible and that it comes to an optimal ripe at the same time. In contrast to the harvest procedure treshing the harvest of the complete biomass does not demand a simultaneous ripe. In the fodder cultivation and particularly in the pastures mixed species are also usual on high intensity level. The first aim of the cultivation of mixed cropping systems are higher and more constant yields on less productive locations and smaller intensity level than by sole cropping systems.

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The yields of efficient sorts in pure seed with known yield components are purposefully affected by the fertilization and protected at the same time against pests and weeds, are not attainable however. Therefore mixed cropping systems seem particularly suitable for organic farming and the cultivation of sandy soils. In Mecklenburg-Vorpommern approximately 27% of the agricultural used area is assigned to the poorer soils. It concerns all natural location units D1, D2 and the not groundwater influenced soils of the D3 locations.

On sandy soils and especially on not groundwater influenced sandy soils smaller productive capacity and yield stability limit the crop rotation. Animal husbandry in Mecklenburg- Vorpommern only has a subordinate importance. The cycle of carbon particularly necessary for a sustainable management of sandy soils cannot be ensured by this extremely small extent of animal husbandry. In addition the small straw yields are not sufficient for an exclusively straw fertilization in order to achieve a positive humus balance on these locations. Thus the locations, which water supply depending exclusively on precipitation differ in view to biomass production substantially from the remaining locations in Germany. Biomass production for energetic use can contribute to an extention of the crop rotation and thus to an increase of the diversity of species.

From the variety of known fodder plants for the cultivation on sandy soils only those crops where selected for the investigation, which seemed suitable for a biomass production in a mixed cropping system. That also includes “forgotten” crops like Melilotus albus, Camelina sativa and Carthamus tinctorius.

Within the project “Mixed cropping systems for the fermentation gas production on sandy soils” following aims are pursued: • examination of suitable fodder plants and grain fruits on compiled criteria for mixed cropping systems, • determination and comparison of the achievement of crops in sole and mixed cropping systems, • investigation of ”forgotten” crops with high biomass yields, which are suitable due to specific characteristics for sandy soils.

Das Projekt wird mit Mitteln des BMELV gefördert und von der Fachagentur Nachwachsende Rohstoffe (FNR) betreut

189 Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

Energy maize – The influence of production technique on the yield of biomass and biogas

I. Klostermann

LFA M/V - State Research Centre of Agriculture and Fishery Mecklenburg- Vorpommern, 18276 Gülzow, Germany

Problem definition The use of regenerative energy sources is inevitable. The finiteness of fossil sources of energy and the climatic load lead to the use of renewable raw materials in the energy sector. The German Renewable Energy Law (EEG) offers favourable basic conditions. Promoted by „The Renewable raw materials bonus“ and the energy plant premium the biomass for the biogas production became a genuine alternative to conventional production for farmers. In the year 2005 70.000 hectares of maize were cultivated for biogas production in Germany. At present there are about 3000 agricultural biogas plants with a total electrical capacity of 500 megawatts in Germany. In Mecklenburg-Vorpommern about 50 biogas plants were in operation at the end of 2005. The economy of biogas plants is not only affected by their technology, but also by the used biomass. In typical maize regions energy maize for biogas production is superior to other field crops because of its high potential of yield, its good mechanized cultivation and good fermentation quality. Depending on yield and quality approx. 17.000 KW/h can be produced with the energy maize yield of 1 hectare. The requirements of energy maize production are very high. High dry matter yields with dry matter contents between 28 and 35% are very important. At the same time however the cultivation of maize raises some questions to the biogas production: • Does energy maize require another technique of cultivation? • Are there particularly suitable maturity groups? • Do the new varieties of energy maize have higher yields of dry matter and methane per hectare? We tested the influence of harvest time; variety and plant density on the energy maize yield under the conditions of Mecklenburg-Vorpommern on the experimental fields Gülzow and Vipperow since 2004. Late maturing energy maize varieties were integrated. The yields of methane l/kg oD.M. (Organic Dry Matter) were calculated by the formula of Baserga [1]. I had no investigation possibilities at present. The laboratory of the LFA determines the input for this formula: the values crude protein, crude fibre and crude ash. The digestibility and the crude fat content were infered from the “DLG - Feed Value Table for Ruminant” according to

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the dry matter content. The used method can reflect the actual methane yield only roughly; it should not be used for economic calculations. It permits however a tendentious estimation of the biogas yields and a comparison between different substrates. The harvested crop of this cultivation tests was not ensilaged, the analysis was made on the fresh mass. With optimal ensiling the crop loses of 10% dry matter. This loss of dry matter is not included in the calculations.

Results and conclusions

2004/05 Gülzow

Dry matter content % Yield of dry matter dt/ha Gülzow / Average 2004/05 Gülzow / Average 2004/05 250 45

40 200

35

30 150

25 dt/ha % 20 100

15

10 50

5

0 0 PR39A98 (240) Gavott (250) Atletico (280) Nexxos (270) Benicia (280) Amandha (320) PR39A98 Gavott (250) Atletico Nexxos Benicia Amandha (240) (280) (270) (280) (320) Varieties Varieties

Yield of methane l/kg oD.M. Yield of methane per hektare m³/ha Gülzow / Average 2004/05 Average 2004/05

7000 350

300 6000

250 5000

200 4000

150 m³/ha 3000 l/kg oD.M. 100 2000

50 1000 0 0 PR39A98 Gavott (250) Atletico Nexxos Benicia Amandha PR39A98 (240) Gavott (250) Atletico (280) Nexxos (280) Benicia (280) Amandha (320) (240) (280) (270) (280) (320) Varieties Varieties

End Sept. Beginning Okt. Middle Okt. End Okt. Figure1: Cultivation test “Harvest time”

In 2004 a cultivation test was established for „The determination of the optimal harvest time for biomass maize in view to a high biomass production and maximum biogas output with high portion of methane “in Gülzow (Figure1and 3). Eight sorts of different maturity groups are harvested in three-way repetition at four different harvest times. The varieties include a maturity group spectrum from 240 to 700. The variety “Doge” with the maturity group 700, impressed in a cultivation test of varieties in the exception year 2003, did not convince at all

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in 2004, likewise the variety “KX 2386” (400). The dry matter content was too law. Therefore the variety spectrum was changed in the year 2005: The varieties of the maturity group 250 “Fantastic” and 260 “ES Charles” were taken instead of “Doge” and “KX 2386”. In both years the maize was tilled on 28th April. The first harvest was in 2004 and 2005 at the time of the beginning of the silo maize harvest in the region. The further three harvests took place in the fortnightly distance. That succeeded very well due to good climatic conditions in the years 2004 and 2005. The figures represent only the varieties, which were examined in both years. For the ensiling and storing quality a dry matter content of 28% to 35% is important. That was a problem on the first harvest time of the late maturity groups. The variety of the maturity group 400 obtained the necessary dry matter content only at the last harvest time. Most varieties reached the highest dry matter yields at the second or third harvest time. The variety “Atletico” (280) obtained the highest yield of dry matter, whereby the dry matter content was not sufficient at the first harvest time. The varieties of the maturity group 240 and 250 and the variety Benicia (280) offer higher security concerning dry matter content (Figure1; Table1).

Table 1: Optimal harvest time for energy maize 2004/05 (Gülzow)

Variety/ 240/250 270/280 320 Maturity group

dt D.M./ha D.M. % dt D.M./ha D.M. % dt D.M./ha D.M. %

1.Harvest time * 173,2 28,6 171,1 25,0 169,4 23,0

2.Harvest time 186,9 32,5 189,8 28,5 181,6 26,1

3.Harvest time 180,3 36,8 190,0 32,5 186,9 28,2

4.Harvest time 173,2 39,8 176,7 36,7 179,6 31,6

*1. Harvest 1.10.04 and 20.09.05, next harvests in fortnightly distance

The portion of methane (Vol %) was between 51,7 and 52% over all varieties and harvest times relatively constantly. Clear differentiations show up in the methane yield m ³ /ha, caused by the differences in the yield of dry matter. “Atletico” (280) and “Gavott” (250) had the highest yields followed of “Amandha” (320) (Figure1).

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2004/05 Gülzow

Dry matter content % Yield of dry matter dt/ha Gülzow / Average 2004/05 Gülzow / Average 2004/05

35 250

30 200 25

150 20 % dt/ha 15 100

10 50 5

0 0 Gavott(250) Atletico(280) Mikado(500) Gavott(250) Atletico(280) Mikado(500) Varieties Varieties

Yield of methane l/kg oD.M. Yield of methane per hectare m³/ha Gülzow / Average 2004/05 Average 2004/05

7000 350

6000 300

5000 250

200 4000

150 m³/ha 3000 l/kg oD.M. 100 2000

50 1000

0 0 Gavott(250) Atletico(280) Mikado(500) Gavott (250) Atletico (280) Mikado (500) Varieties Varieties

8 Crop/m² 10 Crop/m² 12 Crop/m²

Figure 2: Cultivation test “Plant density”

On the cultivation test “Plant density” the maize was tilled on 28th April in both years. The maize was harvested 2004 on 4th October and 2005 on 13th October. “Atletico” shows the higher dry matter content with the highest plant density. But “Gavott” shows the higher dry matter content with the smallest plant density. “Atletico” obtains the highest dry matter yield with 12 crops /m ² and 30% D.M.. However plant densities of over 10 crops /m ² lead to water stress on most locations in Mecklenburg-Vorpommern. The variety “Mikado” does not achieve the demanded dry matter content at the harvest time. The influence of the plant density on the methane yield l/kg oD.M. is not evident. The methane hectare yield reflects the dry matter yield (Figure2). A maize variety with high dry matter yield is very important for the biogas production. The methane yields calculated on basis of the estimate formula of Baserga (l/kg oD.M.) is only a first orientation. Too late harvests cause decreasing yields in the crop rotation. The cultivation tests were continued in the year 2006.

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Figure 3: Cultivation test “Harvest time” Gülzow

[1] Keymer, U.; Reinhold, G.: Grundsätze bei der Projektplanung; Handreichung Biogasgewinnung und –Nutzung. Fachagentur Nachwachsende Rohstoffe e.V. Gülzow, pp.182-209, 2005

194 Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

State and perspectives of biogas production using agricultural raw materials in Mecklenburg-Vorpommern

Dr. Wolfgang Schumann

State Research Centre of Agriculture and Fishery Mecklenburg-Vorpommern, 18276 Gülzow, Germany

Introduction

Favourable political basic conditions in Germany led to a remarkable development of the biogas production. The new German Renewable Energy Law (EEG) guarantees a fixed electricity tariff to operators of biogas plants for a period of 20 years. This consists as a function of the capacity of the biogas plant of a basic remuneration from 0.084 €/kWh up to 0.115 €/kWh for the smallest units and additional different extra payments. For agricultural biogas plants is the extra payment for the use of renewable raw materials of special interest. The so called NawaRo-bonus is 0.06 €/kWh for plants up to a electrical capacity of 500 kW. The NawaRo-bonus creates the economical basis for using agriculturally produced biomass in biogas plants.

Altogether the EEG improved the conditions to the generation of electricity from biomass via biogas substantially and led to an investment boom in the branch. The objective of this study was to establish a representative overview of the reached status of the biogas technology in Mecklenburg-Vorpommern.

Development of the number of biogas plants in Mecklenburg-Vorpommern

Up to the end of 2005 about 50 biogas plants with an installed electrical capacity of approximately 20 MW were in operation in Mecklenburg-Vorpommern. The predominant part of these plants is integrated into agricultural farms. In the meantime numerous biogas plants are under construction or in planning phase. Approximately 100 biogas locations with an installed electrical capacity of over 86 MW are expected in Mecklenburg-Vorpommern until 2007. The main part of this high increase will be generated by two large bio-energy parks. Each of them consists of 40 standardized 500 kW modules (figure 1).

195 Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

48 plants in operation, 17.7 MW 8 plants to be build 4.3 MW 45 projects in planning, 64.7 MW

Figure 1: Locations of biogas plants in Mecklenburg-Vorpommern (12/2005)

Investigations in selected biogas plants

Technology of biogas plants and typical problems

The examined biogas plants were mainly built in 2002 and 2003. Regarding size and technical equipment they correspond with the present average of the agricultural biogas plants in Mecklenburg-Vorpommern. In the mean the biogas plants have an installed electrical capacity of approx. 325 kW and a reactor volume of approx. 2000 m³. The livestock numbers of the concerned farms varies between 330 and 2,300 large animal units (LU) and is in average about 1,100 LU. The plants exclusively work in the mesophile temperature range of 37 to 43 °C. The majority of them work with a one stage process only. Further data regarding the facilities are arranged in table 1.

Technical failures in the plants occur mainly in the block heat and power station (BHKW), the mixing and pumping equipment as well as the desulphurization. In some facilities the biogas process is disturbed frequently by foam formation or floating material in the reactor. Only a few plants are sufficiently equipped with measuring technique for process control. This concerns in particular gas counter and technique for gas analysis as well as for the accurate quantity collection of substrates and for heat measurement.

196 Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

Table 1: Selected data of biogas facilities

Parameter Specification Type of reactor 90% vertical reactors (fully mixed), 10% horizontal reactors (plug stream) Number of reactors 30% 1 reactor, 60% 2 reactors (parallel and/or row), 10% >2 reactors Addition of substrates 80% mash in a agitating container, 20% direct solid dosage Storage biogas Foil storage with capacity of 250 to 350 m³ over reactors Desulphurisation 90% biological (50% internal, 40% external), 10% chemical BHKW 90% injection gas engines, 10% gaseous-fuel engines

Use of basic substrates and co-substrates

Besides farm manure cattle and pig liquid manure and also cattle and poultry solid dung, only renewable raw materials are used in all plants. The portion of the farm manure of the substrate input is in average 83 % (table 2).

Table 2: Frequency of use and proportion of farm manure

Substrate Relative Proportion of the total substrate frequency of use (%) (% of plants) Minimum Average value Maximum Cattle liquid manure 70 10 63 98 Pig liquid manure 40 48 70 95 Cowshed manure 20 7 8.5 10 Poultry manure 20 1.5 4.7 8 Farm manure, total 100 48 83 99

With the co-substrates the maize silage dominates, which is most frequently used beside cereal grain. Altogether the portion of the renewable raw materials is 16.5% (table 3). At present about 5,000 hectare of silage maize for the biogas production are cultivated in Mecklenburg-Vorpommern. Area requirements for the cultivation of silage maize will increase to approximately 40,000 hectare until 2010.

Table 3: Frequency of use and proportion of renewable raw materials

Co-substrate Relative Proportion at the total substrate frequency of use (%) (% of plants) Minimum Average value Maximum Maize silage 90 2 7.8 23 Crushing grain 70 1 3.8 7 Grass silage 40 0.5 1.2 2 Remaining animal feed 20 1 3.5 6 Rye silage of the whole plant 10 19 19 19 Silage of sorghum s. 10 9 9 9 Renewable raw material, total 100 1 16.5 52

197 Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

Process parameter

Important process parameters such as reactor load, retention time, methane productivity and degradation rate of organic dry matter (odm) show partially a very high range. The highest reactor load was found in single-step plants with 3.7 kg odm/m³×d. At the same time very short hydraulic retention times of ca. 23 days were measured and therefore the degradation rates of only 43% are unsatisfactory. With lower reactor load and double retention time, two- stage plants show clearly better degradation rates of 61% in mean.

The specific methane productivity (referred to the reactor volume) varies from 0.5 to 0.85 m³

CH4 / m³×d. These values are typical for NawaRo-facilities (table 4).

Economic viability

The specific investment costs referred to the reactor volume are with 481 €/m³ in average of all plants comparatively high. Related to the installed electrical capacity in mean approximately 2,900 €/kW were invested. Therefore the examined plants are within the optimal range from 2,000 to 4,000 €/KW. With 6,000 full load hours per year the average operating time of the BHKW´s is comparatively low. This corresponds to an average electrical utilization ratio of 68%. Possible causes are longer down-times in some plants and the over-capacity of some BHKW´s. In table 5 some characteristic economical numbers of the biogas plants are arranged.

Table 4: Selected process parameters of biogas plants in Mecklenburg-Vorpommern

Parameter Dimension Average value Range Reactor volume, total m³ 1968 500 – 3.700 Installed electric capacity kW 326 65 – 495 Dry matter content of substrate mixture % 10.7 6.5 – 17.1 Portion of renewable raw materials % 16.6 1 – 52 Hydraulic retention time Single-stage plants days 23 18 – 35 Two-stage plants days 47 25 – 72 Reactor load Single-stage plants kg odm/m³×d 3.7 2.1 – 4.8 Two-stage plants kg odm/m³×d 2.7 1.6 – 3.9

Specific methane yield lNCH4/kg odm 242 148 – 449 Degradation rate of the organic substance Single-stage plants % odm 43 31 – 55 Two-stage plants % odm 61 43 – 78

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Table 5: Selected characteristic economical numbers of biogas plants

Characteristic number Dimension Average Range value Specific investment costs related to reactor volume €/m³ 481 257 – 818 related to installed electrical capacity €/kW 2,920 2,180 – 3,550 Annual full load hours of BHKW h/a 6,000 3,500 – 7,500 Specific maintenance and repair costs €/kWh 1.5 0.7 – 3.3 Specific costs of the biogas plant (without costs of €/kWh 9.1 7.1 – 11.0 co-substrates) Specific costs of power generation €/kWh 12.9 7.8 – 19.3

Conclusions

In the examined agricultural biogas facilities in Mecklenburg-Vorpommern substantial differences regarding the operational reliability of the systems and process engineering, substrate employment as well as in the processing and in process stability were found. The plants are operated with comparatively high reactor load and short retention times. For the majority of the plants this leads to insufficient degradation rates and small gas yields. The desired gas and power production is often not reached. For an efficient process control the necessary measuring technique is often missing.

Altogether, there are numerous possibilities to optimize the process for the majority of the examined biogas plants.

199 Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

The ecological cost of the use of biomass of plants for energy production

Bohdan Deptuła Poznań University of Technology, Chair of Thermal Engineering Poznań, Poland

The comparison of productivity of energetistic plantations and the average logging from forests requires the answer to the question how great is the actual, complete ecological cost of these ways of meeting the energy needs. In the climatic conditions in Europe, the near- natural productivity of forest ecosystems amounts to 1÷2 tons of dry matter from hectare, while the maximal dry matter yields of Miscanthus sinensis “Giganteus” in these climate conditions can reach the value ca 40÷45 t d.m./ha. The difference between gross and net energy yield calculated only as a result of the formal energy balance for all components of the process of plant biomass production is not sufficient to determine the load of the environment. Indeed, the gross calorific value of dry-plant biomass, depending on the contents of the hemicellulose, cellulose, lignin and resins, is contained in the relatively narrow range 15-20 MJ/kg, but its producibility-worthiness is very different. First of all, the chemical composition of the fast growing plants in comparison with chemitype of wood is disadvantageous for their thermal conversion. In particular, significantly greater content of such aggressive elements as chlorine, potassium and sulfur, and many times greater content of ash, increases capital expenditure and exploatation cost. In the paper the ecological cost of plant biofuel is calculated as a cumulative consumption of exergy of unrestorable natural resources appearing in the entire chain of the production processes leading from raw materials taken from nature to the final product. For example, there are presented the results of exergy analysis of conversion of chemical energy of miscant biomass into heat and electrical energy using the technology of bistageous gasification. The sustainability factor, defined as the ratio of actual ecological cost to the specific exergy of the useful product, is calculated for various practical realizations of such a cogeneration system.

The paper specifically considers two boundary cases of exploitation: ƒ cogeneration production of the maximum possible amount of electrical energy, and thermal energy only as “heat waste”, ƒ cogeneration with the use of part of the produced electrical energy to drive a heat pump which enables deep cooling of the generated gas.

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The calculations of the sustainability factor presented in the paper concern the cogeneration system whose nominal electric power amounts to 100 kW and which was designed as a small non-industrial, communal plant.

For the first way of exploitation, the sustainability factor amounts to 0.24 in the case of onestage gasification, and reaches the value of 0.38 when bistageous gasification of miscant biomass is realized. This factor determined for coal power station attains the value ca 3.2. Thus, the utilization of plant biomass to produce electric energy significantly reduces the depletion of unrestorable resources. In the case of cogeneration of electrical energy and low-temperature heat with the use of heat pump installation, the sustainability factor amounts to 4.2 and the exergy effect of such chain of production processes is many times lover than exergy consumption of unrestorable resources.Also in this case the depletion of unrestorable resources will be emphatically lower in comparison to consumption of unrestorable energy carriers in a traditional heating station.

The consideration of only useful products in cited calculations limits the conclusions to the systems fulfilling the conditions of the principle of sustainable development. If not, and in the designing of a new production process, the objective function formulated for the minimization of the consumption of natural resources should comprise all the final products.

Author Information Bohdan Deptuła Poznań University of Technology, Chair of Thermal Engineering ul. Piotrowo 3, 60-965 Poznań, Poland phone: 0048 61 6652215, fax 0048 61 6652281 e-mail: [email protected]

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Optimisation of the fuel supply for the biomass plant Demmin

Simon Zielonka, *Dr. Mathias Schlegel, PD Dr. Norbert Kanswohl Institute for Productive Livestock Animal and Technology, University of Rostock, Rostock, Germany

Summery Changes in the fuel supply process would have positive effects on the economics of the 24 MW biomass power plant in Demmin. The most important quality parameter of the fuel is it’s water content. The water content affects directly the fuel supply process elements transport and storage. A reduction of the water content of the fuel by 8 % could save the power plant 14 % of it’s fuel costs. Changes in the ash removal could save the power plant more than 63 % of it’s ash removal costs.

Introduction In the framework of cooperative research between the professorship of technology and process engineering of the sustainable agriculture and the biomass plant Demmin the fuel supply process is checked for possibilities of improved efficiency. There is room for improvement because there are problems with the fuel quality and as a consequence there is high fuel consumption and high fuel costs (Figure 1). This thesis is aimed at finding ways to reduce the relative fuel costs by raising the fuel quality.

Cost distribution

70,00

60,00

50,00

40,00

30,00

20,00 Share in totalShare costs 10,00

0,00 s s y e l s e va i ts ee o cos oy ctricit iomass pl e tenanc suppl r B m El n nce/ due E ai a ng the M Ash rem O erati Insur p O Costs

Figure 1: Cost distribution of the biomass power plant in Demmin

202 Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

To achieve this a comparison of the literature and the fuel supply process was carried out. The comparison was structured by the elements of the fuel supply chain: production, transport, handling, storing, drying and cleaning. The elements where checked for alternative processes, costs, performance and influences on fuel quality. The database is the data collected at the fuel receiving point and other records of the power plant of the year 2005. There where also interviews taken with fuel suppliers.

Results There are two different types of fuels used in the power plant: wood from forestry and wood from landscape conservation. The power plant acquires logs and wood chips. The costs of fuel production for forestry wood [1] and wood from landscape conservation are lower than in the sighted literature (Table 1). For the production there is no apparent opportunity for greater improvement. Table 1: Example of the production costs of a fuel supplier

Costs of machine use Output Costs Type of machine €/ h m3/ h €/ m3 €/ GJ Hydraulic hedge cutter 72,50 27,70 - 55,50 1,30 - 2,62 0,45 - 0,91 Wood chipper 180,00 70 2,57 0,89 Tractor with trailer 68,00 35 1,94 0,67 Total 320,50 - 5,81 - 7,13 2,01 - 2,47

In the chapter titled ‘transport’ there was a differentiation made between logging transport and woodchip transport. The costs of transportation are lower than in the literature. A way to reduce the amount of needed lorries is the predrying of the logs. To off set the additional costs to the fuel suppliers, the excess profit made by the power plant by saving on transportation and fuel costs, is high enough. This profit can then be used to compensate suppliers for their higher production costs. For the transportation of the woodchips there are walking-floor-lorries and container-lorries in use. The cost of woodchip transportation is also lower than in the literature. The transport distances (50 – 250 km) are a lot higher than in the literature (max. 70 km). A 10 % reduction in the water content of the fuel would save 15 % on the transport costs (Table 2). At the handling stage, there was also a difference to be found between the logging handling and the woodchip handling. The handling of the logging is done by the log lifts of the lorries. Special handling machinery is not in use. A comparison of the costs was not possible, because the handling costs are not shown separately in the literature. They are included in the transport costs.

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Table 2: Influence of the water content on the transport costs Water content Needed truck loads a) Transport costs b) % Truck loads/ a €/ a Difference to the year 2005 (€/ a) 15 2.173 175.809,32 -81.437,92 20 2.332 188.670,71 -68.576,52 25 2.517 203.562,40 -53.684,83 30 2.732 221.006,32 -36.240,91 35 2.988 241.720,10 -15.527,13 38,22 3.180 257.247,23 0,00 40 3.297 266.718,22 9.470,99 45 3.678 297.483,23 40.236,00 50 4.157 336.270,89 79.023,66 a) average load capacity of the year 2005 of 22 t b) average transport costs of the year 2005 of 80,89 €/ truck load Comment: bold line: Data of the year 2005

At woodchip handling there is more variety in the methods of loading employed than there are described in the literature. The method of transhipping a container from the chipping machine to the lorry is not described in the literature yet. There are many possibilities for storing and drying the logs along the fuel supply process. If the logs are stored in a sunny and windy place a reduction of the water content from 50 % to 30 % is possible in a storage period of spring to autumn [2]. However attention must be given to the bark beetle. The predrying of a part of the log batch before transport is possible. When storing the woodchips the loss of dry matter is the biggest problem. The woodchips have a water content of 38 % when they reach the power plant. They are stored without coverage on a non-metallic surface. The loss of dry matter during the storage period is unknown. To measure exactly the loss, the water content of the fuel has to be known. But the water content of the logs is unknown. A useful way for measuring the water content of the logs is not available. Here research is still needed. The machines used for chipping and shredding the fuel materials are state of the art. If the fuel is dirty the suppliers are using sieves to clean the fuel. At the power plant the fuel is also cleaned intensively. There is no room for improvement. But there is still a fraction of the fuel in use which over exerts the conditioning/ cleaning machines. Another part of the thesis was to research ways to reduce the disposal costs of the ash. The amount of ash was 14.29 % of the fuel weight in 2005. To reduce the costs two ways were researched: • the reduction of the amount of ash and • cheaper ways of disposal.

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The amount of resulting ash is affected by impurities like mud. Changing the fuel supply process reduces the amount of fuel needed. If one uses a higher quality fuel, less of it is required and consequentially there is less ash production. The ash production would shrink. Another way to reduce the ash produced is the drying of the ash. The power plant uses a ash removal system working with water. 45 days of storing the ash in a hall reduces the water content about 10 % (Table 3). Further research is needed into the drying process of the ash.

Table 3: Water content, amount of ash and ash removal costs after 45 days of storage Ash removal Ash after 45 days of Unit Ash Difference costs (€/ t) storage Water content % - 38,92 28,72 10,20 Ash production t - 9.769,00 7.826,10 1.942,90 16,00 156.304,00 125.217,60 31.086,40 Ash removal costs €/ a 12,25 119.670,25 95.869,72 23.800,53

By using the possibilities to reduce the amount of ash before and after the conversion, 63 % of the ash removal costs could be saved. The ash currently is disposed of in a landfill. A better way would be the utilisation of the ash, for example as a fertiliser in forestry or agriculture [3]. The quality of the ash for this is good enough. But some more tests are needed. A handy way of utilising the ash would be to mix the ash with compost in composting plants because the machines used have no problems with the stones in the ash.

Literature [1] WITTKOPF, S.; HÖMER, U.; FELLER, S. 2003: Bereitstellungsverfahren für Waldhackschnitzel - Leistungen, Kosten, Rahmenbedingungen. In: LWF-Wissen Nr. 38. Bayerische Landesanstalt für Wald und Forstwirtschaft. Freising. ISSN 0945-8131. Download datum: 06.02.2006 http://www.lwf.bayern.de/imperia/md/content/lwf- internet/veroeffentlichungen/lwf-wissen/38/lwf-wissen_38.pdf [2] GOLSER, M.; PICHLER, W.; HADER, F. 2005: Energieholztrocknung – Endbericht. Kooperationsabkommen Forst - Platte - Papier. Wien. Rev.: 12.12.05, Download datum: 11.04.06 http://www.fpp.at/pics/download/energieholztrocknung_endbericht.pdf [3] MARUTZKY, R., SEEGER, K. 1999: Energie aus Holz und anderer Biomasse - Grundlagen, Technik, Entsorgung, Recht. DRW-Verlag Weinbrenner GmbH & Co Leinfelden-Echterdingen. ISBN 3-87181-347-8

205 Use of Bioenergy in the Baltic Sea Region - Proceedings of the 2nd IBBC 2006, Stralsund, Germany

HEAT TRANSFER IN TUBE BUNDLES - AS THE CRITICAL LINK - BY TAKING OVER ENERGY FROM BIOMASS FURNACE TO DRIVE A STIRLING ENGINE

Prof. Dr hab. inż. Tadeusz BES Department of Heat Engineering, Szczecin University of Technology*), Al. Piastów 17, PL-70-310 Szczecin, Poland

Abstract The system consisting of a biomass-furnace and a Stirling engine as an electricity generator is analysed from thermal point of view. The analysis is focused on a selected element of such a system i.e. a block with a bundle of tubes located in the furnace in the way of combustion gases. The working fluid circulates between the cylinders of the Stirling engine and inside the tube bundle, in which the gas flow is arranged as a co-directed cross-flow. For any given number of tubes in the bundle other ways of switching between tubes are also analysed. The tube bundles have also been examined for various proportions of mass flows in the apparatus. Moreover a whole spectrum of NTU is taken into account. Due to low combustion heat of biomass the temperature of combustion gas is relatively low (below ~800oC). This is not sufficient to achieve adequate thermal efficiency, which is significantly below the efficiency of a conventional power plant. Therefore by improving the conditions for heat transfer within the tube bundle it is possible to increase the gas temperature as much as possible and also efficiency of the system. Thus, proper operation of the bundle is the critical element for the examined device.

1.- Introduction The application of the Stirling engine for electricity generation by using biomass furnace has attracted the attention of engineers and environmental specialists for many years. The analysis is focused on electricity generation by the power station with some important features/advantages in comparison to the well-known classical stationary or traction power stations. These features include the elimination of the water-cooling system including a condensation system, which takes up large space and has significant weight. Due to technical difficulties with obtaining very high heat flux concentration on very small surface and the necessity to achieve high temperatures in the Sirling motor, the idea of

*) The thermal analysis of the cross-flow tube bundles were investigated during the author’s stay at the Helmut Schmidt University of the Federal Armed Forces, Hamburg, Germany working over the problem together with Prof. W. Roetzel

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Stirling brothers (patented in 1816) was implemented in practice more than 100 years later. It was so despite the fact that their idea itself was more than 60 years ahead of the Otto and Diesel motors inventions. Until today Stirling engines (known as “Dish/Stirling”) found practical application being driven by solar radiation from a field of mirrors positioned parabolic-ally in regions where the engine can be exposed to intense solar radiation and where there is lack of the water, e.g. a desert.

2.- Stirling motor droving by wood-biomass-furnace

The subject of analysis is furnace of middle or small heat-power (~50 kW) fired by the wood- biomass. The selection of proper furnace is difficult due to its specific task and demanded high temperatures. The air heaters accessible in commerce are suited to the temperatures up to ~200oC. Therefore the individual designee of the proper furnace seems to be necessary The combustion process runs in burning chamber. Behind of the chamber in the way of combustion gas by its outlet the tube bundles are installed (Fig. 1.) that play similar role as after-heater in conventional steam furnace. Further these bundles is called as the “receiver”. Its task is taking over amount energy from combustion gas as high as possibly to transfers it into the working gas that circulates between the furnace and head of the Stirling motor. Fuel to furnace consists of wood-biomass: waste of wood/lumbers or „pellets”. There is diffrent opinion about amount of ash after combustion processes. From some measuring data follows that amount of ash in these products is almost negligible, but in the literature there are signals that this amount is considerably high, as well. This depends on the fuel and its preparation. In situation when ash particles appear they should be removed – what could be done in the furnace with two drafts of combustion gasses, since by changing gas direction the solid particles having usually different density from that of combustion gas are rejected by inertion forces. This reduces partly the ashes at least. To collect the rejected ash in furnace the special shield was built in (see Fig. 1).Due to very small values of heat transfer coefficient from combustion gas to working fluid in tubes of receiver these tubes have to be finned. But the dust that is transported together with combustion gas settles on installed fins. From heat transfer point of view It is very disadvantageous process since dust-sediment conducted heat extremely poor what affects very badly heat transfer to working gas. Finally after short time dusty gas that caused sedimentation could reduce remarkably effect of fins installation.

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2.1.- Mine idea by taking over the energy in biomass-furnace The heat stream generated in biomass-furnace is taking over by working gas similarly as it has been done in conventional water boiler. In such the boiler the main amount of heat is transferred in combustion chamber. In the biomass-furnace the combustion chamber should be shielded with tubes of working fluid similarly as in boiler. Now transferred heat flows from burning flame mainly by radiation. Next in the way of combustion gasses the heat exchanger (receiver) has to be placed that consists of the tube bundles with working fluid inside and the stream of combustion gas passing bundles outside. They are arranged in so called the co- directed cross-flow. As it was mentioned the tube bundles have to take over the possibly highest amount of energy insuring in that way the maximum possible temperature of working fluid. The thermal calculations of such heat exchangers are the main goal of present report.

Thermal efficiency of the Stirling motor– that uses two constant volume processes and two isotherms - follows the relation well known from literature e.g. [1]:

η =1−T /T S min max (1)

This effectiveness is based upon two temperatures Tmin and Tmax i.e. the minimum and maximum temperature in the cycle. Thus the high temperature Tmax determines high engine efficiency. For this reason in present report so remarkable attention is paid to high value of this temperature. The real effectiveness of Stirling motor is far from excellence rendered by equation (1), however, rising of this temperature shows the proper way of improving the real efficiency. The low value of Tmin depends on good properties of the cooler quality. This very important question, however, is not subject of present report.

2.2.- Singularity of heat transfer in tube bundles For thermal analysis of flows in tube bundles the special attention should be directed to the fact that heat transferred from combustion gasses to the tubes pass at the constant pressure (almost constant) but for working fluid values of pressure oscillate. These oscillations are expected by keeping constant value of specific volume v=const (density ρ=const). It is in accordance to principle of the Stirling motor and is valid in the time of single cycle at least. Therefore, the frequency of engine revolution should be compared to the time that is needed to pass the tube bundles by working fluid.

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3.- Thermal calculations of “receiver”

Further analysis is focused on the selected element of such system i.e. the “receiver” being the tube bundles and placed in furnace in the way of combustion gas. A working fluid circulate between cylinders of the Stirling motor and inside of tube bundles whereas the flow in bundles and combustion gas is arranged as the co- directed cross-flow. The tube bundles have also been examined for any given number of tubes in the bundle other ways of switching between tubes. The different mass stream proportions of gas in apparatus are also analysed. Moreover a whole spectrum of NTU (the number of heat transfer units) from 0 to ∞ is taken into account. As the basis for such calculations serve the theory developed in papers of Schedwill [2] and of Bes & Roetzel [3,4,5]. In the last reports the method of mean weighted temperature of outside fluid and the log mean temperature difference correction factor was used. They allow for analyse of different cross-flow arrangement for the counter-directed and the co-directed cross-fluid-flow arrangements with one or many passes for any tubes in bundles within working fluid inside.

3.1. Geometry of receiver

The receiver should be suited to the channel of furnace. It could be cylindrical or rectangular in cross-section. Further three geometries of the channel and receiver with tube bundles will be taken into account in present paper:

- Firstly - Many cylindrical tubes are bent accordingly to the involutes of the small basic circle - see paper [6] and figure 2 - and are positioned in one plain forming discs. Set of many such discs made the receiver shaped generally as a cylinder. The tubes are feed by working gas in the axis of basic circle and left the receiver on its perimeter. By using involutes for cylindrical channel the combustion gas pass the tubes perpendicularly to tubes (discs) and due to such shape of axes the uniform flow distribution is insured. - Secondly - many tubes are bent accordingly to screw lines that together create the ring. Set of many concentrate rings of constant ring distance made receiver shaped cylinder as a whole. The tubes are feed by gas on one bottom of cylinder from collector to each ring and to each tube and left the receiver on its other side gathered working gas in collector as well (Fig. 2.).

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- Thirdly - Set of many tubes with equal length lying parallel create single plane. Analysed is couple of such planes under condition that the switch over between tubes runs alternately from one tube-plane to another one. Many such of couples that are set together made receiver shaped as parallelepiped (see Fig 3.a and b). All of these receiver geometries have one property: From thermal point of view they can be calculated accordingly to one pattern flow configuration. This is co-directed counter cross-flow. The proposed by Hausen [7] name is as in origin “Gleichsinnig Kreuz-Gegenstrom”.

3.2. Thermal theory of co-directed counter cross-flow [3,4,5]

The co-directed counter cross-flow arrangement is shown in Fig. 5. Let us consider a single tube i from the bundle. The numeration of tubes has been set in reverse order to the flow direction of outside fluid. The symbols used here are listed in the nomen- clature.

In order to determine the relationship between effectiveness P, surface area A, overall heat transfer coefficient and fluid temperatures the energy conservation relation for each fluid, augmented by boundary conditions, is applied. The temperatures T and ϑ - of working gas and combustion gasses, respectively - shown in nomenclature - are expressed in dimension- less form. The overall heat transfer coefficient is assumed to be constant for all tubes in the bundle. Finally, by using other dimensionless parameters, also explained in nomenclature, the energy balance for the tube-side fluid flowing in the ith tube takes the following form: dT = ntu (T − ϑ ) (2) dη i i where ntu means number of transfer units per single tube n and length of tube single section lo: NTU/n/lo, n number of tubes in bundles.

The energy balance for the fluid outside the tube is given by

ϑi +1/ 2 − ϑi −1/ 2 = ntu⊥ (ϑi −Ti ) (3) Symbol, ϑ , means the average temperature of fluid passing outside the ith tube. The necessity of using two local reduced temperatures ϑ i-1/2 and ϑ I+1/2 of the fluid flowing outside the tubes will become obvious. These are the temperatures at the locations where a thermal effect boundary, between the tubes denoted by; i-1 and those denoted by i+1, can be defined. Now, there are two equations (2) and (3) with three unknown variables ϑ i, ϑ i±1/2 and Ti. They have to be found. These equations do not have a unique solution unless

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additional information about the distribution of dimensionless temperature ϑ i between boundary temperatures ϑ i-1/2 and ϑ I+1/2 is available. To solve this problem Bes & Roetzel [4] have developed a method in which the average temperature ϑ i has been defined the weighted average of the temperatures ϑ i-1/2 and

ϑ I+1/2

ϑi = ωϑi −1/ 2 + (1 − ω)ϑi +1/ 2 (4) where ω is the weight-parameter. Meaning of parameter is as follows:

1 1 ω = − (5) 1 − exp(−ntu⊥ ) ntu⊥ It has been used in a paper [4] that the temperature of outside fluid changes its value exponentially along the perimeter of a tube. The reasoning is explained short in [4].

After mathematical transformations the above system of equation can be presented in short notation. Energy balances of gas in tubes and outside tube follows:

dT =B (T − ϑ ) (6) dη i i−1/ 2

ϑi −1/ 2 − μϑi −1/ 2 =(1 − μ)Ti ) i=1,2,3…n (7) where μ and B denote:

μ=exp(-ntu┴ ) and B=(1- μ)/R (8)

System of difference -differential Eqs. (4,5) has to be completed by the boundary conditions for the flow arrangement shown in Fig. 5.

3.3.-Analytical solution to the problem of tube bundles For any kind of heat exchanger it would be desirable, if possible, to derive an exact formula for the effectiveness P and present it in an explicit form. For the co-directed counter-current cross flow heat exchangers, the case being considerate is possible to obtain such a relation. To develop a procedure leading to this aim let us use the set of all equations based on the switchover condition of the fluid in tubes (see Fig. 5).

The solution to this problem becomes easier when it is divided into two steps: In the first one, a general solution of the set of Eqs. (4), (5) will be obtained. This leads to a set of

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integration constants. In the second step using boundary conditions regarding temperatures of the fluid entering the tubes the values of these constants will be calculated. Further it is assumed that the heat transfer coefficient takes into account both convection and radial coefficients and moreover they are independent on coordinate η. Whole procedure for solution to this problem is presented in paper [3]. Its results offer the relation for effectiveness P of bundles and can be shown as follows:

Firstly the polynomials pi(σ) and wi should be defined. They are:

j i ⎛ j −1⎞ σ i pi (σ) = σ∑ ⎜ ⎟ and w i = μ p[B(1/ μ −1)] (9) j =1 ⎝ i −1⎠ i! where σ means: σ=η (4/R) sinh( ntu⊥ /2).

-1 Further following notation will be used: ε=exp(-B) and w=1/ε-μ[4R sinh( ntu⊥ /2)]. The auxiliary parameters δi with I=2,3,4,…n can be obtained after assuming δ0=1, δ1=w and by using recurrent relation:

j =i k=i −1 δ =w − w / δ I=2,3,4,….n-1 (10) i ∑ j =2 j ∏k=i − j +1 k Finally the thermal effectiveness of co-directed counter-current flow configuration is expressed as:

i =n−1 P =1 − e −B / δ (11) ∏i =0 i It is to be emphasized that compact relation for thermal calculations of flow arrangement shown in Fig. 5. is valid only for each single tube in an exchanger (bundles). The relative number of transfer units ntu ⊥ =NTU/n/l0 remains constant. Nevertheless, for the effectiveness P of the co-directed counter current cross-flow arrangement under consideration this is an exact expression.

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a) c)

b)

Fig. 1. Fig. 3. General view of system considering of the biomass- Side a) and top/bottom b) views of tube bundles furnace and the Stirling engine to drive an electrical bent accordingly to screw lines and set in form of generator: 1) burning chamber, 2) main entrance of air, concentric rings, c) path of tube axes 3) more air, 4) after-burning chamber 5) tube bundles, 6) exit of combustion gasses, 7) shield for rejection of ashes, 8) hot cylinder of Stirling engine, 9) (cold cylinder) of Stirling engine compressor, 10) regenera- tor, 11) cooler

Fig. 2. Fig. 5. View of (disc) top or bottom of tube bundles bent Co-directed counter-current cross-flow arrangement up to involutes of small basic circle

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versus thermal effectiveness P for the co-directed counter- P for the co-directed effectiveness versus thermal Θ . Normalized mean temperature difference difference mean temperature . Normalized current cross-flow. Number of tubes in bundles; a) n=10 and b) n=20 and b) a) n=10 of tubes in bundles; Number cross-flow. current Left tubes between over switches and of flow arrangement view General Fig. 6

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3.4. Radiation heat transfer in the channel with tube bundle Although the radiation heat transfer in a biomass furnace in not as large as in a coal- fired furnace due to lower temperatures, it has to be included in the energy balance. It is the exchange of radiation energy: - Between the walls of the channel where the block is located and the tubes, gas and dust; - Between the exhaust gases containing gases absorbing the energy and the ambience; - Between the particles carried by the exhaust gases and the tubes and channel wall; and between the tubes themselves.

For the examined case the calculation of configuration coefficients εr-c according to the classical formula (containing quadruple integral), so important in the radiation heat transfer, is impossible due to the extremely complex geometry of the tubes and channel walls. The experiment has to be used as a basis.

The radiation of gases such as CO2, H2O and CO is a band radiation (on axis of wavelength), and the integral of its intensity is not proportional to the fourth power of 4 temperature, however, as usually general radiation relation with Tgas will render it. Despite this, a general formula for calculating the radiation heat flux is adopted:

A substitute value Te (equivalent temperature) is adopted for the temperature of combustion gases, dust and channel walls. Finally, the formula for the heat flux qr can be determined based on experiment and expresses using a parabolic function. This reflects the linear change of the radiation heat transfer coefficient with relation to temperature. Indeed there is more complicated function. For radiation energy transfer the standard relation from literature is used;

−8 4 4 qr =Ccεw −e10 [(Te ) − (Tw ) ] (12) where Tw means the tube wall temperature. By using some mathematical transformation the radiation component of heat transfer can be expressed with help of working gas temperature. κ Thus q ≈ κ (T −T ) + 2 (T −T )2 (13) r 1 e 2 e

2 2 where κ1 and κ2 means κ1 = ∂qr / ∂T and κ2 = ∂ qr / ∂T both derivative for Tw=Te. The extension of the energy balance equations (2) and (6) by using the formula (13), which now has the form of a Bernoulli equation, and its further transformation make it

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possible to maintain the linear form of the energy balance equation, with all the implied advantages:

4,- Numerical illustration of theory – Effectiveness of tube bundles

Having such relation as (11) at one’s disposal it is easy to calculate parameter δi recursively and then effectiveness for such flow configuration of tube bundles with the high number of tubes. In Fig. 6.- for any NTU values and any heat capacity rate ratio, dimensionless mean temperature difference Θ have been plotted against effectiveness P for n=10 and n=20 rows of tubes. For various number of n=1,2,3,4,5,7,1015,20, 50 and 100 the relations for the effectiveness regarding flow arrangement under consideration were earlier reported in literature [ 3]. There-fore in this paper the charts with relations e.g. mean temperature Θ versus P are omitted. It can be noted that with increase in number of tubes in a bundle the effectiveness of such exchanger approaches the value of effectiveness the counter current flow arrangement. However. Even for very high values of NTU and n the difference between effectiveness’s cannot be neglected e.g. for n=20 and large NTUs (>5) it approaches 21/2 %. By using the present method we are able to take care of all divergences, including, these smaller one.

5. Conclusions Prior to the experimental verification of the whole device, the verification of its elements has to be carried out, primarily with regard to the block with the tube bundle. Usually such experiments should be preceded by theoretical thermal calculations, being the purpose of this paper. - The theory presented in the report offers a good tool for theoretical evaluation of the block with tube bundles arranged in the co-directed counter current cross flow. - It is advised that for practical applications the higher number of tubes in bundle should be taken i.e. n=10, n=20 and more. For a high number of tubes the thermal efficiency of the bundle approaches the value for a counter-current heat exchanger. - Small values of NTU are not recommended, not only due to low efficiency, but also due to the fact that they reduce the favourable influence of the configuration type on its efficiency.

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- The proportions between the streams of combustion gasses and working medium are included in the theory as the R parameter being the quotient of heat capacities of the streams. - Installation of fins on the tubes significantly improves heat transfer conditions, but creates possibilities to accumulation of deposits on them as well. The finning and especially adjusting the distance between fins should be a result of compromise between the improvement of heat transfer conditions and the cost increase caused by frequent removal of fouling and maintenance of the device. - Based on the experiments regarding the block with tube bundles, one has to determine the very important factor of radiation heat transfer and especially the influence of the tubes' wall temperature on such a heat flux. The function of radiation stream depending on the temperature could be replaced with a parabolic function without losing the advantage of linearity of the problem, important for theoretical calculations. - Forcing the flow by using overpressure improves the heat transfer, but this improvement is limited due to the fact that excessive overpressure may lead to depressurization of the combustion chamber. Selection of one out of three geometries of the block (Fig. 2,3 and 4) has to be the result of measurement of pressure loss and the analysis of the resistance of tubes.

Literature [1] Rogers. G.; Mayhew. Y.: Engineering Thermodynamics – 4th edition; Longman – Scientific Technical, John Wiley & Sons. Inc. New York (1994) pp.270 [2] Schedwill, H.: Technische Anwendung von Kreuzstromwärmeaustauschers, Fortschritts- Ber. VDI.-Z. Reihe 6 (1968) [3] Bes, Th.: Thermal performances of co-directed cross-flow heat exchangers, Heat & Mass Transfer 31 (1996), 215-222: Springer-Verlag (1996) [4] Bes,Th.; Roetzel. W,: Verlauf der Fluidtemperaturen im Querstromrohrbandel. Wärme- und Stoffübertragung28 (1993) 457-463. (written on the basis of report for Stifterverband für die Deutsche Wissenschaft 1982/83 [5] Roetzel W.: Chapter C in Heat Atlas (VDI-Wärmeatlas Springer 2000. [6] Bes, Th.: Spiral Heat Exchanger in new geometrical and thermal aspects. Procee-dings of the Twelfth International Heat Transfer Conference: pp.387-392 (2002) [7] Hausen, H.: Die Wirkung des Austauschers von Rekifikationsboden, I. ang. Math. Mech. 17 (1937) 25-37. [8] Трухов В., С.; Турсунбаев, И., Я.; Умаров, Г., Я.: Parameter calculations of inside heat transfer outline of Stirling engine (in Russian): Scientific Academy of Uzbek Republic, Uzbek SSR, Tashkent 1979

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Fig. 4. Co-directed counter current cross flow tube bundles a) module units of tube bundles. b) block of heat exchangers (tube bundles) set of any (here five) units

Nomenclature Greek symbols A heat transfer surface area, [m2], ε notation of exponent, e-B, B parameter, Eq. (8), Θ dimensionless mean temperature C heat capacity rate, [W/K], difference, P/NTU, lo length of single tube, [m], ϑ dimensionless outside fluid temperature, NTU number of transfer units, kA/C, (t-tin)/(t⊥,in-tin), ntu number of transfer units for single tube, μ auxiliary parameter, e-ntu⊥, NTU/n=kA (nC), ω weight factor, Eq. (7), ntu⊥ number of transfer units of outside fluid for one tube and length of single tube section, NTU┴/n=kA/(nC⊥), Subscripts n number of tubes in the bundle, P effectiveness of the heat exchanger, ⊥ refers to combustion gas, in inlet of temperature. R heat capacity rate ratio, C/C┴, T dimensionless temperature of tube-side,

fluid (t-tin)/(t⊥,in-tin), t,t⊥ fluids temperature, [K],

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