Diamondiaal Compendium

DIAMONDIAAL COMPENDIUM

A circular community for the future

(S)ACT-Group 1689

Alexander Boedijn Anne Tjallingii Anouk Stam Carlotta Meriggi Mona Regad

Preface

In this compendium, we put together a collection of detailed information about numerous sustainable technologies in relation to water, energy and food production. These sustainable technologies could be implemented in the future community Diamondiaal, in order to make it an off-grid and circular community. In this document, all working mechanism are explained, together with their advantages and disadvantages. Taking that information into account, we assessed how feasible the technologies would be for the community Diamondiaal by ranking them. This technical compendium could be of great help in the decision-making process of what technologies to implement in the community. Decisions that need to be taken in terms of technologies, are dependent on the priority setting: it is more important to create a circular community that is completely off the grid? Or is it more important to build the community together with all inhabitants and create a high level of solidarity? Both choices would also have consequences for the costs.

There are several people and organisations we would like to thank. First of all, we would like to thank Amal Abbass-Saal, director of Inspiratie Inc. and founder of the future community Diamondiaal. Furthermore, we would like to thank Astrid Hendriksen, our connection between Wageningen University and Inspiratie Inc. Finally, we would like to thank Nora Sutton, who guided us with her expertise, and Gerard Jagers op Akkerhuis, who coached us as a team.

Table of content

INTRODUCTION ______5 EXISTING COMMUNITIES ______7

QUARTIER VAUBAN, FREIBURG, GERMANY ______7 DE CEUVEL, AMSTERDAM, THE NETHERLANDS ______8 SCHOONSHIP, AMSTERDAM, THE NETHERLANDS ______9 VERENIGING AARDEHUIS, OLST, THE NETHERLANDS ______10 HAMMARBY SJÖSTAD, STOCKHOLM, SWEDEN ______11 MEETINGS WITH EXPERTS AND STAKEHOLDERS ______12

FABCITY ______12 EXPERT MEETING WITH PROF. DR. IR. ZEEMAN ______14 VISITING INSPIRATIE-INC ______15 QUALITATIVE CONSTRAINTS ______17

GENERAL DIVISION OF THE LAND WITHIN OOSTERWOLD ______18 CONSTRAINTS REGARDING ECOLOGY ______18 CONSTRAINTS REGARDING SOIL AND WATER ______19 LANDSCAPE ______20 QUANTITATIVE CONSTRAINTS ______21

HOUSEHOLD REQUIREMENTS: ENERGY AND WATER ______21 GEOGRAPHIC CONSTRAINTS ______23 WATER AND HUMANS ______27

WATER HARVESTING ______27 WATER TREATMENT ______31 WATER STORAGE ______36 FOOD AND WATER ______38

HYDROPONICS ______38 AQUAPONICS ______39 HUMAN AND FOOD ______41

COMPOSTING ______41 GREENHOUSE (ALSO GLASSHOUSE OR HOTHOUSE) ______44 VERTICAL FARMING ______46 WINDOW FARMING ______48 COLD FRAME ______49 ENERGY AND HUMAN ______50

SOLAR THERMAL ENERGY ______51 SOLAR PANELS FOR ELECTRICITY ______53 WIND POWER ______56 ANAEROBIC DIGESTER SMALL-SCALE ______58 COMBINED HEAT AND POWER (CHP) ______61 HEAT PUMP ______63

WOODCHIP BURNERS ______65 BIOMASS GASIFICATION ______68

BIOMASS FURNACE FOR RECOVERING CO2 FROM FLUE GASES ______70 WATER AND ENERGY ______71

BUFFERS ______71 HEAT EXCHANGERS ______73 MICROBIAL FUEL CELLS ______74 EXPLANATION SCENARIOS ______77 RECOMMENDATIONS ______83

FINANCIAL ANALYSIS OF EACH SUSTAINABLE TECHNOLOGY ______83 SOIL AND BUILDING RESTRICTIONS ______83 PHONE APPLICATION FOR BETTER COMMUNICATION WITHIN DIAMONDIAAL INHABITANTS ______83 FOCUSSING IN THE DETAILS ______83 REFERENCES ______84

TABLE 1. GENERAL DIVISION OF THE LAND IN OOSTERWOLD ACCORDING TO THE MUNICIPALITY ...... 18 TABLE 2. GAS CONSUMPTION IN DIFFERENT TYPES OF BUILDINGS...... 21 TABLE 3. ELECTRICITY DEMAND IN THE NETHERLANDS...... 22 TABLE 4. WATER DEMAND IN THE NETHERLANDS...... 23 TABLE 5. COMPARISON OF ROOFING MATERIALS RUNOFF COEFFICIENTS ...... 29 TABLE 6. SPF AND QUSABLE FACTOR VALUES SUGGESTED BY EUROSTAT...... 64 TABLE 7. COMPARISON OF ENERGY CONTAINED IN VARIOUS TYPES OF FUELS. MC = MOISTURE CONTENT .... 65 TABLE 8. REVIEW OF FUEL STORAGE OPTIONS...... 66 TABLE 9. AMOUNT OF BIOMASS NEEDED FOR HOUSEHOLD HEATING IN THE DIAMONDIAAL VILLAGE...... 67 TABLE 10. GRADING OF SELECTED TECHNOLOGIES FOR COMPARISON...... 76

FIGURE 1. LAND DIVISION AND PLANNED DEVELOPMENTS OF THE DIAMONDIAAL PLOT...... 5 FIGURE 2. SCHEMATIC REPRESENTATION OF THE SYSTEMS USED IN DE CEUVEL ...... 8 FIGURE 3. SUSTAINABILITY PLAN FOR THE SCHOONSHIP AMSTERDAM ...... 9 FIGURE 4. OVERVIEW OF ENERGY, WATER AND WASTE FLOWS IN HAMMARBY SJÖSTAD...... 11 FIGURE 5. WORKING PRINCIPLE OF A UASB...... 14 FIGURE 6. AREA PLANNED FOR THE DEVELOPMENT OF OOSTERWOLD...... 18 FIGURE 7. AVERAGE, MONTHLY RAINFALL IN THE NETHERLANDS...... 24 FIGURE 8. DAILY SUM OF GLOBAL RADIATION. THIS DATA REPRESENTS THE AVERAGES PER MONTH FROM THE PERIOD 1951 – 1980...... 25 FIGURE 9. AVERAGE, YEARLY WIND SPEED FROM DATA GATHERED BETWEEN 1981-2010...... 25 FIGURE 10. MONTHLY, MEAN TEMPERATURE IN THE NETHERLANDS...... 26 FIGURE 11. EXAMPLE OF A ROOF HARVESTING SYSTEM WITH TRANSPORT AND STORAGE FACILITIES ...... 28 FIGURE 12. EXAMPLE OF THE LAYERED COMPONENTS OF A GREEN ROOF...... 30 FIGURE 13. DIFFERENT STAGES OF THE WATER TREATMENT PROCESS...... 31 FIGURE 14. SCHEMATIC REPRESENTATION OF THE BIO-SAND FILTERING SYSTEM IMPLEMENTED AT DE CEUVEL ...... 32 FIGURE 15. SCHEMATIC REPRESENTATION OF AN OZONATION PROCESS ...... 34 FIGURE 16. SIMPLE HYDROPONICS UNIT ...... 38 FIGURE 17. SMALL-SCALE AQUAPONICS UNIT...... 39 2 FIGURE 18. GLOBAL IRRADIATION IN THE NETHERLANDS ON A YEARLY BASIS IN KWH/M ...... 50 FIGURE 19. BIVALENT SYSTEM WITH A SUN COLLECTOR AND A CENTRAL HEATING SYSTEM) ...... 51 FIGURE 20. VARIOUS COMPONENTS NEEDED FOR A FUNCTIONING SYSTEM...... 54 FIGURE 21. WORKING PRINCIPLE OF A WIND TURBINE...... 56 FIGURE 22. EXAMPLE OF ANAEROBIC DIGESTER ...... 59 FIGURE 23. SCHEMATIC REPRESENTATION OF A CHP SYSTEM...... 61 FIGURE 24. VAPOUR COMPRESSION CYCLE4: 1) CONDENSER, 2) EXPANSION VALVE, 3) EVAPORATOR, 4) COMPRESSOR...... 63 FIGURE 25. DIFFERENT COMPONENTS OF A DOMESTIC BIOMASS BURNING SYSTEM...... 66 FIGURE 26. SCHEMATIC REPRESENTATION OF A DOWN-DRAFT GASIFIER WITH THE VARIOUS PROCESSES INVOLVED...... 68 FIGURE 27. PROTOTYPE AND DESCRIPTION OF THE PURIFICATION PROCESS COMPONENTS...... 70 FIGURE 28. TANK BUFFER TYPES...... 71 FIGURE 29. GREENHOUSE BASEMENT BUFFER...... 71 FIGURE 30. WORKING PRINCIPLE OF A HEAT EXCHANGER. SOURCE: PRECISION GRAPHICS...... 73 FIGURE 28. GENERAL OVERVIEW OF BIOELECTROCHEMICAL SYSTEMS. ON THE LEFT AN OVERVIEW OF THE MICROBIAL FUEL CELLS ARE SHOWN ...... 74

Introduction

The ‘Diamondiaal’ project is carried out by Inspiratie Inc., a non-profit organisation located in Almere, The Netherlands. The aspiration to develop a sustainable and circular community arises from the values promoted by the organisation, namely cooperation and participation, while supporting diversity and citizen empowerment. The long-term goal is to achieve a sustainable and self-sufficient living by drawing from the principles of circularity and providing space for expression of initiatives by inhabitants, in a multicultural context. The development of Diamondiaal takes place within the municipality of Almere’s project of extension called Oosterwold. Within the 50 ha of Oosterwold, the city allocated 2 ha to Inspiratie Inc. for implementing their vision of the intercultural and global village ‘Diamondiaal’. On this parcel, land is assigned to various purposes and activities. As depicted on the Picture below, Diamondiaal combines housing with social enterprising. In parcels A, B and C, social housing for about 60 individuals. This will be developed and managed by a housing corporation. In the white parts on the fringes of the representation and in parcel E, private housing by 4 families is planned, and land has already been bought by certain households. The central piece of land is devoted to the building of a community centre, where catering, educating and nursing facilities will be installed, alongside ateliers for artists. This space is open not only to residents, but also to the general public.

Figure 1. Land division and planned developments of the Diamondiaal plot.

There is a vision for Diamondiaal and existing plans such as the one above carried by Inspiratie Inc., but there is an important knowledge gap concerning the actual design and implementation of the village. This is why Inspiratie Inc. commissioned the WUR Science Shop to provide expertise through our work. They gave us the opportunity to build from the resources, enthusiasm and creativity in place towards a sound analysis and study of the potential solutions. In our limited timeframe, we defined our scope in the most feasible way and set ourselves the task of identifying several combinations of sustainable techniques relating to energy, water and food production that complement each other and function in a circular way. In these systems, the outputs of one is an input for the other, and vice versa. Supporting interconnections between these systems is the first step for a circular community, with partially self-sufficient inhabitants able to produce their own energy through renewable resources. We are at the beginning of a journey that will involve multiple groups and parties and our work is the stepping stone for further investigation of creating a sustainable and circular community.

Existing communities

The concept of a sustainable and self-sufficient Diamondiaal village is innovative, as there is no known example of a fully circular community. However, this project draws from famous cases of ‘ecovillages’ and sustainable neighbourhoods, as well as recent initiatives receiving attention. In this part, we will introduce certain of these communities, in the Netherlands and abroad.

Quartier Vauban, Freiburg, Germany

The Quartier Vauban in Freiburg is an iconic example of sustainable urban development. Starting in 1993, the aim was to build a new neighbourhood in a cooperative and participatory way, while promoting ecological, social, economic and social values. This eco-district houses today 5,500 inhabitants and launched advancements in the domains of mobility, public space, social interaction and energy (www.vauban.de 2016).

Energy

Picture 1. "We [the people] Solar energy is widely implemented throughout the district, make the world as we like it!" with 450 m2 of solar collectors and more than 3,700 m2 of (Gorges, 2011) solar panels. A co-generator plant was built by the municipality in complement to satisfy energy demand (www.vauban.de 2016). Housing units were built according to low energy construction standards (maximum energy use of 65 kWh per m2 per year). In addition, some developments included passive houses (requiring 15 kWh per m2 per year), which generate more energy than they consume, as well as ‘plus energy’ houses, which electricity surplus is redistributed in the network (Stadt Freiburg im Breisgau 2011). Water Measures were taken to reduce water use in the neighbourhood, and limit the impact of living on water resources. This includes the use of dry toilets and waste water treatment systems for reuse in household appliances (toilets and washing machines) and watering plantations. Green roofs and green surfaces are maximised in the district to harvest rainwater and prevent water runoff.

De Ceuvel, Amsterdam, The Netherlands

This more recent urban development differs from the one above as it was initiated by citizens. The city provided a 10-year lease for the development of the project, but financing was limited. This piece of land has important constraints, as it consists in a former industrial area in the north of Amsterdam and its soil is heavily polluted. Therefore, houseboats were used and no underground systems were chosen. It is today home to a dynamic ground of offices, ateliers, businesses and catering facilities.

Figure 2. Schematic representation of the systems used in de Ceuvel (modified from http://www.metabolic.nl/projects/de-ceuvel/).

Energy Electricity demand is partially satisfied by solar panels. In compliance with the physical constraints of limited infrastructure development into the ground and a restricted budget, high-tech air-to-air heat pumps are used to provide reliable heat during winter, in combination with a heat exchange ventilation system. These require electricity from the grid to function, but can later be provided through renewable sources (Metabolic 2014). Water De Ceuvel, as an experiment, is under constant monitoring by specialists. Rainwater harvesting is under study for drinking and irrigation purposes. They use bio-sand filtering as a technique for water treatment. Besides, dry toilets from the brand SanoMar are used to reduce water use and waste water production, while producing reusable biomass for composting. They are also experimenting with a struvite reactor to remove phosphates from urine and using it as a fertilizer.

Schoonship, Amsterdam, The Netherlands

This recent development is also part of the movement that attempts at rethinking urban systems in a durable way, namely “[creating] an urban ecosystem that is not in conflict with the natural environment and the economy” (Metabolic 2016).

Figure 3. Sustainability plan for the Schoonship Amsterdam (modified after Schoonschip Amsterdam 2016).

In the north of Amsterdam, 47 households are planned. They target to be 70 % water self-sufficient, completely energy self-sufficient, in addition to food production.

Energy At the household level, energy demand is satisfied through solar panels. Heat is provided by a sun collector and a heat pump also for the water.

Water Rainwater is harvested for household appliances, which are chosen as water- and energy-saving, with heat-recycling showers. In the toilets, faeces and urine are separated and a pilot is planned to retrieve nutrients from it to inject in greenhouses (Metabolic 2016).

Vereniging Aardehuis, Olst, The Netherlands

23 houses and a community building are built in Olst, inspired from the ‘Earthship’ concept. This ecological housing project seeks to build energy and water self- sufficient homes by looking at all domains of sustainability, namely People, Planet and Profit. They put forward solidarity as a driving principle and set themselves the objective to promote sustainability as a lifestyle, for example through CO2 neutral building and housing (Vereniging Aardehuis Oost-Nederland, 2016). Energy Solar panels are used to fulfil electricity needs by producing about 63,300 kWh per year. For heating, houses integrate a glass façade south-oriented for natural sun heating. Extra heat is provided by wooden stoves and heat pumps. Water A composting toilet system is in place, and wastewater is treated by a reed bed filter. Only the community building is connected to the sewage system.

Hammarby Sjöstad, Stockholm, Sweden

At a much larger level, the city of Stockholm rehabilitated a harbour area into a vibrant innovative neighbourhood. The city set objectives in energy use and waste reduction and closing the loops was an important factor in the design of technologies. With massive financing, this urban development hosts today more than 25,000 people and provided innovative solutions in the matters of storm water management, high-tech waste sorting and transportation for example.

Figure 4. Overview of energy, water and waste flows in Hammarby Sjöstad (Lausanne.ch, 2016).

Meetings with experts and stakeholders

FabCity

Fabcity is an event taking place from 1st of April until 26th of June on Java Island in Amsterdam. This event displays 50 innovative installations and examples of self- sustaining technologies. People with various backgrounds helped building this sustainable urban area. More than 400 students with very different educational backgrounds are involved in the project, including artists, entrepreneurs, and professionals.

Picture 2. Left: Sustainers Homes. Right: Heijmanshome (picture by ACT-1689)

Sustainers Homes

A great example in which our group was very interested was the ‘Sustainers Homes’. This organization made modular and mobile self-sufficient houses. The Sustainer Homes are able to provide for the water- and energy demand that is needed for the usage of a home throughout the year. They claim to be completely off-the-grid. Because this is closely linked to our project, we consulted them for detailed information.

For the water demand, they have placed a rainwater catchment mechanism on the roof, which is cleaned by reverse osmosis so it can be consumed by people. For grey wastewater and urine, they used an helophyt filter. This filtered water can be put back in nature solely if people would use biodegradable detergents. For this filtering, the IBA certificate system is used. They remove nitrate and phosphate, which means a reduction up to level 3a according to the IBA system. Furthermore, it

12 depends on the policy of the area where you would live how clean this wastewater should be. For the black waste stream, they use a composting toilet from the brand ‘Separett’. There is constant ventilation in the toilet to avoid odours. If the faeces are compact and dry, it can be useful for composting.

For the energy demand, they implemented solar heating, but they will change this to an air- to-air heat pump. Furthermore, they implemented solar panels and a little windmill to provide for the electricity demand. They have batteries for a backup when there is not enough energy storage through solar panels alone. They mentioned that the windmill provides only 600 W, which almost does not contribute to the total electricity demand. That is why they will leave the windmill out of their next model.

Stand from Waternet

This stand had some interesting techniques regarding water filtering. They use biogas insulation and biogas heating. Their representant told us they could recover the phosphate from urine, which can be used as fertilizer. For these mechanisms, they used a vacuum toilet. In addition, the heat converter they used was presented proudly, as it allows them to recover 50% of the heat that is released by the shower. The heat exchanger is easy to implement and can be combined with solar heating and solar panels.

Picture 3. A fancy solar panel of Green Choice (picture by ACT-1689).

Expert meeting with prof. dr. ir. Zeeman

Prof. dr. ir. Zeeman holds a personal chair in the Department of Environmental Technology at WUR and works part-time as a senior consultant at LeAF. Her field of expertise includes anaerobic digestion and waste water treatment. The first subject of interest is that she has implemented a dry toilet system in her own home and connected it to a UASB (upflow anaerobic sludge blanket). A UASB (figure X) is a type of anaerobic digester that uses a suspended sludge in which bacteria live and break down organic matter.

Figure 5. Working principle of a UASB1.

Whenever surplus sludge is removed, she uses it as a fertilizer in the garden. She states that in order to be sure all pathogens are gone, a period of 6 months is needed. Ongoing research is aiming to reuse sludge on a larger scale for agriculture. However, post-treatment of the sludge to remove pathogens proves to be difficult. Prof. dr. ir. Zeeman also indicates that the UASB indeed functions less well in winter time due to lower temperatures. Furthermore, the choice of which type of toilet system to use is important. It is recommended to use a system in which the flows of urine and faeces are not diluted. By using a lot of water to flush away excreta, the volume increases and the concentration of nutrients goes down. Proven technologies that could be implemented in Diamondiaal are vacuum toilets, composting toilets and waterless

1 Retrieved from http://www.sswm.info.

14 urinals. For each of these systems, the level of social acceptance would have to be discussed with future inhabitants. Prof. dr. ir. Zeeman recommended that handling and processing of excreta should be done in a centralised way, in order to reduce individual contact with pathogens, and thus the risk of diseases. A central vacuum station for transport of excreta would be a possibility. This system is up and running in Sneek, where a project called 'Waterschoon' started to experiment with new ways of sanitation. Unfortunately, Prof. dr. ir. Zeeman also indicated that a centralised system such as the one in Sneek is economically feasible at a minimum of 1200 users. It may be a project for the whole of Oosterwold (50 ha) rather than just Diamondiaal. However, she did express interest in a possible pilot program only for Diamondiaal, in cooperation with WUR.

Visiting Inspiratie-Inc

On the 7th of April, we visited the organisation Inspiratie Inc. located in Almere for the second time. In our first visit to Inspiratie Inc., we had a short meeting in which we mainly introduced ourselves. During the second meeting, a lot of potential inhabitants of Diamondiaal where present. During this day, we learned more about what the organisation Inspiratie Inc. stands for and what they feel passionate about. Inspiratie Inc. creates opportunities for everybody who wants to participate in society.

We met and talked with refugees and asylum seekers. They had very diverse backgrounds and skills. We met a visual artist who loves to paint, sculpt, design and organise workshops for schools. He has a daughter of 2,5 years old and a son of 4 months old. If he obtains a residence permit, he would love to live in Diamondiaal. Besides him, we spoke to several others including a barber, a cook, a photographer, an artist, a journalist, a writer, a history teacher and several people who love to take care of children. We saw a very diverse group with different backgrounds, skills and home countries. They all really want to start and build a new life for themselves and their families here in the Netherlands.

Besides this, we got familiar with the vision of Diamondiaal by Amal Abbass-Saal. We drove together with her to the piece of land in which Diamondiaal will be in 20 years. At this point, there is not much activity on this piece of land and most of it is still untouched. After the visit of the area, we drove back to the building of Inspiratie Inc., where Amal Abbass-Saal showed us several ideas of building types and architectural ideas. Pictures of these can be seen in the section Qualitative Constraints.

We discussed some important issues for our project. Amal Abbass-Saal mentioned that there will be around 60 people living in the 1.74 ha. There should not be too much traffic, because it needs to be a friendly and calm environment for children to play outside. Another important comment she made, is the name of the area director of Oosterwold, which is Yvon Noot. There will be at least one connection to the grid

15 in the community house that is going to be built within Diamondiaal. This also functions as a backup solution in times of need. The community house should be a place hosting parties and a place to interact with the inhabitants and visitors of the village.

We had a very fun and educational day in Almere and we obtained a much better view of what Inspiratie Inc. and Diamondiaal exactly stands for.

Qualitative Constraints

The government wants Almere to grow stronger. Plans for the development of Oosterwold are since 2006 developed by the municipalities of Almere, Amsterdam and Zeewolde, the Provinces of Flevoland, Noord-Holland and Utrecht, Waterschap Zuiderzeeland and the national government. Spread over a large area, 15,000 homes are going to be built and vary in form and size (large villas and starter- homes). A large amount of people will be working at home and shops, companies, schools are spread over a large area. Most of the transportation in Oosterwold will be by car. Therefore some roads in Oosterwold will be predefined by the municipality.

The inhabitants see Oosterwold as their land, because they will be involved in the process from the beginning. The development of Oosterwold has few rules and thus creativity of initiatives is supported. A key figure is the area director, who advises and stimulates initiatives. She will stimulate sustainability, but every initiative can find its own way in this. The houses will be isolated properly and a lot of solar panels will be used. Water purification will happen on the initiatives own land. An ambition which should be pursued by all the initiatives, is that Oosterwold will be self-sufficient and sustainable. There can be a backup system for electricity, heating or green gas, and waste water should be treated and reused as much as possible. This should not be a risk for health nor the environment. One of the initiatives who will buy a piece of land within Oosterwold is Inspiratie Inc. Amal Abbass-Saal is the head of Inspiratie Inc. and has an idealistic vision about this community that will be called Diamondiaal (Gemeente Almere & Gemeente Zeewolde, 2013).

This chapter will cover information about the qualitative constraints within both Oosterwold and Diamondiaal. It will cover the general division of land the municipality wants as a guideline. In addition, some constraints regarding ecology, traffic and soil will be explained. Only the constraints which are important within the boundaries of this project will be used for further assessment of the technical feasibility of this project.

Figure 6. Area planned for the development of Oosterwold.

General division of the land within Oosterwold

The Wet ruimtelijke ordening is a Dutch law which indicates the spatial structure and visions. They contain guidelines for new developments and should be carried out by the municipality. Every initiative within Oosterwold should work within this framework. The general division of land is explained in surface-percentages which is made visible in Table 1.

Table 1. General division of the land in Oosterwold according to the municipality (Gemeente Almere & Gemeente Zeewolde, 2013)

Type Percentage Buildings 20.00 % Concrete surfaces 6.50 % Public green 20.50 % Agriculture 51.00 % Water 2.00 %

Constraints regarding ecology

The Province of Flevoland has stated that the connection of Hoge Vaart and Priembos should stay intact. In addition, the water of Oostvaardersplassen, Leperlaarsplassen and Gooimeer/Eemmeer fall within the Nature Conservation Act. These natural sites are nearby Oosterwold and shouldn’t be disturbed in any way. Subsequently, the general rules of the Flora en Faunawet and the Boswet should be

18 applied. In the southwest of Oosterwold are woods of 20 years old. This is property of Staatsbosbeheer and the public character of this should be maintained.

Constraints regarding soil and water

There are quite some constraints regarding the soil, housing developments and waste water treatment, which are listed below. The most important constraint that affects this project is the soil subsidence of 0.8 meters that is expected in the upcoming 50 years. Due to this, energy suppliers that need to be placed underground cannot be used. Therefore, geothermal heating is not applicable in the whole area of Oosterwold. Besides this, the rules regarding water management have to be taken into account when choosing certain sustainable technologies.

Soil An effective water management is required to keep the soil from being marshy. Because a soil subsidence of 0.8 meters is expected in the next 50 years, there are restrictions for warmth and cold storage systems. This soil subsidence will be a great challenge for the inhabitants to deal with. It could also lead to flooding of the land. The water systems that are going to be used should be able to resist the soil subsidence and extreme weather events.

A drinking water storage is present under Oosterwold and can be used for public drinking water. These wells are protected and are 200 m under the ground. No drilling is allowed there. A few pipelines run under Oosterwold from this drinking water storage. It should not be used for agricultural purposes, but only for household consumption.

Infrastructure There are existing pipelines for gas, water and electricity. Initiatives should think about these when the construction of building takes place.

Flooding risk Due to waterways and ditches, the water drainage will be maintained in an effective way. These are in control of the government. There are no problems related to it at the moment but in the upcoming century, water could be an issue. In that case, the water controller will take measures for this.

Wastewater treatment Groundwater quality should stay the same. Therefore, there are requirements for wastewater. Wastewater processing cannot oppose the Kaderrichtlijn Water guidelines. It has to be conform the health requirements.

Landscape

Wind turbines There is one important constraint explained in the structural vision of the municipality which we need to take into account. This includes, regrouping of wind turbines in the area (including the ones of farmers), in order to improve the appearance of the area. The municipality wants the wind turbines to be more centred at one locations instead of scattered around (Gemeente Almere & Gemeente Zeewolde, 2013).

Design Diamondiaal Amal Abbas-Saal has a general idea about the design of the houses and landscape. She has shown two types of designs which they want to implement. Both are shown in the pictures presented below. The homes in Picture 4 are designed by Peter Vetsch. Mrs. Abbas-Saal has a preference for this type of buildings. If the expenses of this design are too high, there is the possibility that a design from Sustainer Homes (see Picture 5) will be implemented. Next to these designs, Mrs. Abbas-Saal wants the future inhabitants to have an important influence on the general appearance of the village.

Picture 4. Design type 1. Erdhaus by Peter Vetsch2.

Picture 5. Design type 2. Modular house by Sustainer Homes3.

2 Retrieved from http://www.erdhaus.ch/erdhaumluser--earth-houses.html.

3 Retrieved from http://sustainerhomes.nl/portfolio/case-homes/?lang=nl.

Quantitative Constraints

Household requirements: Energy and Water The research presented here is used to attain an indication of energy- and water usage for the average household in Diamondiaal. The indication is considered as the minimum demand and will restrict the search area of sustainable technologies. The restriction aids us to critically select and focus on sustainable technologies that fit the purpose of Diamondiaal. We would like to stress that the minimum demand is used to assess the feasibility of a technology. It does not represent the minimum usage which can be achieved by the residents. The latter is strongly determined by the mind-set and the subsequent consumer behaviour of the residents.

The assumption of an 'average Diamondiaal household' is needed because both energy- and water use depend on the definition of a household. The definition should at least specify the number of people per household (shared resources) and the type of building (insulation). Based on the information obtained from meetings with Inspiratie Inc., it is assumed that around 60 people will live in Diamondiaal. It is also assumed that there will be a total of 20 households: 6 households of 2 persons, 6 households of 3 persons and 8 households of 4 persons. Inspiratie Inc. is considering house designs by Peter Vetsch. If this would fail, the modular houses from Sustainer Homes may be used. Although these types of houses are not easy to categorise we assume that they can be compared to terraced houses, regarding insulation.

Energy

Energy consumption of households in The Netherlands is typically expressed as the electricity- and gas use per year. Gas is mainly used for heating water. Either for space heating or hot water. The gas usage is strongly dependent on the building type because it determines insulation and size. According to Nibud (2016), the average use is less dependent on the number of people living in one house. Table 2 shows several typical Dutch types of buildings and their gas usage.

Table 2. Gas consumption in different types of buildings. Source: RVO 2015

Building type m3 gas per year Flat 940 Terraced house 1310 Corner house 1580 Semi-detached 1870 Detached 2440

However, this is indeed based on the assumption that the burning of gas is used to heat water. If other possibilities for heating water are to be explored then we must know how much energy a cubic meter of gas represents. In the Netherlands a higher

21 heating value of 35.17 MJ/m3 is used to express gas as energy (Energieleveranciers.nl, 2016; “Household Energy Use,” 2016).This means that 1 m3 of natural gas equals about 9.77 kWh. Since many houses in the Netherlands use boiler systems, an average efficiency of 80 per cent is assumed. Taking this into account, a total household heating demand for Diamondiaal can be calculated as follows:

푯풐풖풔풆풉풐풍풅 풉풆풂풕풊풏품 풅풆풎풂풏풅 (풌푾풉 풑풆풓 풚풆풂풓) ퟗ. ퟕퟕ = # 풐풇 풉풐풖풔풆풉풐풍풅풔 ∗ 품풂풔 풖풔풆 ∗ ퟎ. ퟖ

9.77 퐻표푢푠푒ℎ표푙푑 ℎ푒푎푡𝑖푛푔 푑푒푚푎푛푑 = 20 ∗ 1310 ∗ = ퟑퟏퟗퟗퟔퟕ. ퟓ 풌푾풉 푝푒푟 푦푒푎푟 0.8

Please keep in mind that this calculation is based on gas usage and quality of insulation. Sustainable solutions may not have to realise this amount of energy to heat all households.

The use of electricity is mostly dependent on the number of people in the household (Nibud, 2016). Table 3 shows this relationship for the Netherlands.

Table 3. Electricity demand in the Netherlands. Source: RVO 2015

Amount of people in household kWh per year 1 1870 2 2990 3 3660 4 4110 5 4610 6 4930

For the whole of Diamondiaal, based on the total number of residents, this amounts to a total household electricity demand of the following: 푯풐풖풔풆풉풐풍풅 풆풍풆풄풕풓풊풄풊풕풚 풅풆풎풂풏풅 (풌푾풉 풑풆풓 풚풆풂풓) = ∑(# 풐풇 풉풐풖풔풆풉풐풍풅풔 ∗ 풆풍풆풄풕풓풊풄풊풕풚 풖풔풆)

퐻표푢푠푒ℎ표푙푑 푒푙푒푐푡푟𝑖푐𝑖푡푦 푑푒푚푎푛푑 = (6 ∗ 2990) + (6 ∗ 3660) + (8 ∗ 4110) = ퟕퟐퟕퟖퟎ 풌푾풉 푝푒푟 푦푒푎푟

Water

Table 4 shows yearly water usage dependant on the amount of people in the household (Graveland & Baas, 2013; Nibud, 2016; Vewin, 2015).

Table 4. Water demand in the Netherlands.

Amount of people in household m3 water per year 1 46 2 93 3 127 4 159 5 194

Based on this data the total household water demand for Diamondiaal adds up to the following: 푯풐풖풔풆풉풐풍풅 풘풂풕풆풓 풅풆풎풂풏풅 (풎ퟑ 풑풆풓 풚풆풂풓) = ∑(# 풐풇 풉풐풖풔풆풉풐풍풅풔 ∗ 풘풂풕풆풓 풖풔풆) 퐻표푢푠푒ℎ표푙푑 푤푎푡푒푟 푑푒푚푎푛푑 = (6 ∗ 93) + (6 ∗ 127) ∗ (8 ∗ 159) = ퟐퟓퟗퟐ 풎ퟑ 푝푒푟 푦푒푎푟

Considerations  Please note that the data shown here is presented as the demands on a yearly basis. It does not take into account consistency of supply. Daily demand and - supply of energy and water can vary greatly depending on the weather and seasonal conditions (i.e. rainfall, sunlight and temperature).  The great cultural diversity of the Diamondiaal residents is not considered here. Different cultures may have other standards when it comes to a 'pleasant' room temperature, washing, diet etc.  This is an indication for the household demand. It is expected that around 150 people will make use of facilities in Diamondiaal daily. This includes people who will work at and visit Diamondiaal. The energy-, water- and food demands of these visitors are outside the scope of this project.

Geographic constraints

Any piece of land has its own set of environmental characteristics (i.e. climate, soil type, flora and fauna). Because Diamondiaal aims to implement sustainable technologies, the climate factors constraining renewable technologies are explored here.

Rainwater

Average, yearly rainfall at the Oosterwold area is 796 mm (Climate-Data.org, 2016). Which very much represents the rainfall of the Netherlands, which is 800 mm (KNMI, 2016a). Since the Diamondaal area is 17,400 m2, the total, yearly rainfall for that area can be estimated as follows:

푹풂풊풏 풘풂풕풆풓 = 푨풓풆풂 ∗ 푹풂풊풏풇풂풍풍 = ퟖퟎퟎ ∗ ퟏퟕퟒퟎퟎ = ퟏퟑퟗퟐퟎ 풎ퟑ 풑풆풓 풚풆풂풓

Less than 20 % of this water would need to be harvested to meet the yearly water demand of all Diamondiaal households. Figure 7 shows that rainfall in the Netherlands is considerable throughout the year.

Figure 7. Average, monthly rainfall in the Netherlands. Source: KNMI (http://www.knmi.nl/home) Although the Netherlands do not have real draughts, dry periods can occur. April is usually the month with the least rainfall and a worst case scenario would be 30 consecutive days without rain (Effing, 2008). If such a period would occur and no other water sources are available, a buffer capacity is needed to run the households. Assuming that water use is consistent throughout the year the following buffer is needed:

30 퐵푢푓푓푒푟 푐푎푝푎푐𝑖푡푦 = ∗ 2592 ≈ 213 푚3 365

Sunlight

Average, yearly irradiance for the region of Almere is 1000 kWh/m2 (Ternary.eu, 2016; Viessmann Werke, 2008). However, monthly averages differ greatly which means that solar radiation, as a resource, is not very consistent. Figure 8 below shows how the irradiance is distributed throughout the year.

Figure 8. Daily sum of global radiation. This data represents the averages per month from the period 1951 – 1980. Source: KNMI (http://www.knmi.nl/home)

Wind

In the Netherlands, conditions are such that wind can be used as a source of energy. However, this is still very much dependent of the exact location. Error! Reference source not found. shows that the area of Flevoland has an average, yearly wind speed between 4.5 and 5.5 m/s. During the visit to Oosterwold we noticed that wind turbines have been built a mere hundred metres from the building site of Diamondiaal.

Figure 9. Average, yearly wind speed from data gathered between 1981-2010. Source: KNMI (http://www.knmi.nl/home) 25

Temperature

The temperate maritime climate of the Netherlands results in the average monthly temperatures shown in Figure 10. The extreme temperatures are around -10 °C and 33°C (KNMI, 2016b).

Figure 10. Monthly, mean temperature in the Netherlands. Source: KNMI (http://www.knmi.nl/home)

Water and Humans

On average, one person in the Netherlands requires 120 L of water per day (Debets & Bril, 2014). This amount is shared between the toilets (34 L), bath and shower (51 L), dishes and washing machine (22 L), kitchen activities (8 L) and use of the sinks (7 L). Given the purpose of the Diamondiaal village and the commitment to a ‘sustainable living’, the amount of water will likely be adjusted downwards, with the use of energy-saving devices and technologies. In the context of this project, we are looking at flows for potable drinking water for human consumption, as well as water for kitchen activities and showering.

In this section, we review systems and techniques enabling to deliver drinking water to households. Water delivery consists of three steps: 1. water harvest, 2. water treatment and 3. water storage. The methods presented here are drawn from the literature and existing examples.

Water harvesting

Groundwater

Groundwater is an important resource for drinking water, especially in coastal areas. It presents multiple advantages relating to water production, with high-quality, little seasonal variations, low-storage costs and easy exploitation (Vandenbohede, Houtte, & Lebbe, 2009). Groundwater extraction is done through well drilling and pumping. Depending on water quality and the presence of contaminants, more or less complex treatment methods are applied after extraction.

A thorough analysis of the potential of the underground aquifer should be done when considering exploiting it. Resource extraction should not exceed the mean annual recharge rate, otherwise a lowering of the water table may cause land subsidence (Niemczynowicz, 1999). In coastal areas and polders, it can also lead to saltwater intrusion (Vandenbohede et al., 2009), and thus groundwater reserves require to be well managed for ensuring their sustainability on the long-term.

It is a viable option for the Diamondiaal village, but may be complemented with other water harvesting methods to lower the pressure on the environment and diversify the pool of resources.

Roof catchment

Rainwater harvesting is praised for being a ‘free’ source of water, as it only requires storage and treatment costs, for sparing groundwater resources and reducing storm water runoff (Aladenola & Adeboye, 2010). It is a relevant option for buffering water scarcity in developing countries and for climate change mitigation. This source of water is particularly suited for domestic consumption at the household level (Gould & Nissen-Petersen, 1999), as it is close to the user and require little energy for harvest. In this system, the user is in control of his own system and in charge of maintaining it without depending from the community.

This type of harvesting can easily be done by collecting water from roof surfaces, by using a system of gutters and pipes to transport water from the catchment area to the storage facility4. A first filter can be applied before water reaches the tank, to remove leaves and debris. Considering the first rain contains the most contaminants, some ‘first flush’ systems might be preferred to automatically evacuate the first 20-25 L of rain (Villarreal & Dixon, 2005). The choice for filtering system depends on local conditions and the ones requiring Figure 11. Example of a roof harvesting low maintenance should be preferred. system with transport and storage facilities (Khoury-Nolde, 2006)

Quantitative estimation The amount and quality of rainwater depends on the amount of rainfall and surrounding environment, extent of the roof surface and type of roof material. Indeed, each roof material has a different runoff coefficient, which enable to estimate how much water can be collected. Different types of material have various levels of impermeability and thus will retain or allow rainfall catchment through a gutter and pipes system (see Table 5).

4 Galvanised or stainless steel, fiberglass or plastic gutters and downpipes are suitable. The size of the gutter must be appropriate to release water into the tank without water overflow. Splash-guards can be used to prevent overflow and spillage (Li et al., 2010). Gould & Nissen-Petersen (1999) recommend at least 1 c m2 of gutter cross-sectional area for every square meter of catchment area.

Table 5. Comparison of roofing materials runoff coefficients (modified after Mentens et al., 2006; Worm & van Hattum, 2006)

Type Runoff coefficient

Galvanised iron sheets >0.9

Tiles (glazed) 0.6-0.9

Aluminium sheets 0.8-0.9

Flat cement roof 0.6-0.7

Organic (e.g thatched) 0.2

Green roof 0.25-0.5

Some quantitative data are required when designing a domestic rainwater harvesting system, such as the mean rainwater supply, in order to calculate the surface needed for roof catchment.

The following equation can be used to determine the area of roof needed to supply rainwater to a household (adapted from Reijtenbagh, 2010):

푨 = 푺 ÷ (푹 ⋅ 푪풓)

퐴= Catchment area in square meter (m2) 푆= Mean rainwater supply in cubic meter (m3) 푅= Mean annual rainfall in millimeters (m/a) 퐶푟= Runoff coefficient

For Diamondiaal, following our qualitative requirements5, this would amount to a minimum roof catchment area of 3,618 m2 with a runoff coefficient of 0.9 or 8,141 m2 of green roof with a coefficient of 0.4. This difference has to be taken into account when designing the building of the Diamondiaal village, as the volume of water collected through a green roof is much lower than through a less absorbent material. Some combinations of roofing materials might facilitate rainwater harvesting.

5 We base this calculation on the need to supply water to 62 people, divided in 20 households (6 households of 2 persons, 6 households of 3 persons and 8 households of 4 persons). In this equation, S is worth 2592 m3 and R is equal to 796 mm.

Green roofs

Green roofs are usually divided in two categories, extensive and intensive. Extensive green roofs cover wide surfaces and have a shallow substrate (<6 inches). They are light- weight structures that require little maintenance. Intensive green roofs, sometimes referred to as “rooftop gardens”, have a deeper soil (> 6 inches) and include a more diverse vegetation, including small trees and shrubs. They are more expensive and heavier on the

Figure 12. Example of the layered components of a building structure, which must include them in green roof. (Program for Resource Efficient its design. Figure 12 provide an overview of the Communities, 2008) various components of this type of structure. It has to be pointed out that an insulation layer is required when the building is heated or cooled (Program for Resource Efficient Communities, 2008).

Green roofs are dependent on many variables relating to their efficiency. Gromaire et al. (2013) argue green roofs have a high capacity in retaining water, up to 70 per cent on an annual scale, although it depends largely on their structure. Rainwater depth and moisture conditions are important, and long and extensive periods of rainfall in winter can seriously decrease their retention capacities. The thicker the substrate is, the better it can retain water, especially with a dense vegetation vaporising evapotranspiration (Berghage et al., 2007). Harvesting rainwater from green roofs for domestic consumption is a challenge, but can be done by considering certain design criteria. Further research on this topic is recommended.

Advantages6  Aesthetic value  No added pollutants in the water (unlike uncoated metal roofing)  Savings in heating and cooling  Heat island mitigation effect  Habitat creation for flora and fauna

Disadvantages7  High level of turbidity and nutrient content of harvested water  Less capacity of harvest than ‘hard’ materials

6 (Program for Resource Efficient Communities, 2008) 7 (Program for Resource Efficient Communities, 2008)

Water treatment

Conventional water treatment systems and households systems traditionally follow the same basic treatment process of water: sedimentation, filtration and disinfection (see Figure 13). Sedimentation and filtration are simple processes used to reduce turbidity, and improve the effectiveness of disinfection methods. Source protection and safe storage are also important components to prevent salt intrusion (e.g. from where water is drawn) and contamination post-treatment.

Figure 13. Different stages of the water treatment process. (WHO Regional Office for the Western Pacific, 2014)

It is important to stress that water treatment is a process rather than technologies. There is no ideal and standard combination of these, but each method has its own advantages and disadvantages, depending on the local context. Most of them are not exclusive, but work in combination with each other to improve their efficiency.

In this section, we review filtration and disinfection techniques, their benefits and drawbacks, and in a specific section below, present methods integrating the different phases of water treatment. Depending on water quality standards, these techniques should be complemented by disinfection processes.

Bio-sand filtering at De Ceuvel, Amsterdam

It is a rainwater harvesting method based on an average of 0.8m3/ m2/year on a roof surface of 35 m2 (i.e. a daily average of 78 L per day per household). It consists in three 60 L plastic drums, used for pre-storage, filtration, and post-storage. It uses the method of slow bio-sand filtration to trap and remove solid elements, nutrients and microbiological agents. Slow sand filtering functions through layers of sediment, from coarsest on top to finest at the bottom. To make the filtration more effective, a biological layer at the top, where microbiological activity develops in standing water, ensures nutrients and pathogens are eliminated (Helmreich & Horn, 2009; Metabolic, 2014).

Figure 14. Schematic representation of the bio-sand filtering system implemented at De Ceuvel (Metabolic, 2014).

Advantages  Low costs (about € 100,- for a system)  Implementation is easy, one person can set it up in about three hours  High flow rate (≃ 20 L per hour8)  Locally available materials  Effective in removing nitrates, phosphates, suspended solids and, to a certain extent, ammonia (need for more recent data)

Disadvantages  Maintenance is needed. Changing sand every 30-35 days, cleaning up tanks  Limitations of slow sand filters since they can only reduce microorganisms  In this design, there is standing water in the first drum. The input pipe should be placed at the bottom of it to reduce hydraulic retention time and avoid microbiological activity.  Lack of protection in post-storage tank from recontamination

8 (WHO Regional Office for the Western Pacific, 2014)

Activated carbon

Widely used in water filtration systems, an activated carbon treatment system consists in tanks filled with granular activated carbon (granules of carbon-rich materials such as coal, wood, nutshells, etc.). Water is pumped through it and granules adsorb contaminants. Carbon filtering is used on its own (see Picture 6), but is also used in association with UV treatment systems Picture 6. Groundwater treatment system with two tanks of activated carbon or reverse osmosis for an effective disinfection. (US Environmental Protection Agency, 2012). Advantages9  Removes organic chemicals, chlorine, lead, tastes and odours from water  Important technique to use in combination with others

Disadvantages  Potential high costs  Need for maintenance (changing carbon filters, concern for membrane deterioration)  Not suited for bacteria removal, need for further disinfection

Chlorination

Using chlorine is an easy disinfection method (Helmreich & Horn, 2009), although it is not of common practice in the Netherlands. It is done by using chlorine tablets or chlorine gas. It should be applied after the storage phase, so chlorine would not interact with organic matter that might settle at the bottom of the tank and create undesired components.

Advantages  Low costs  Effective in removing pathogens quickly (Safe Drinking Water Foundation, 2016)  Residual protection in the tank to prevent recontamination.

Disadvantages  Some agents show resistance to low amounts of chlorine  Corrosive to some pipes materials such as copper and iron10  Difficulty of dosage  Hazardous by-products  Not commonly used in the Netherlands

9 (Lemley, Wagenet, & Kneen, 1995) 10 (Cantor, Park, & Vaiyavatjamai, 2000)

Solar disinfection

This technique uses solar energy to eliminate pathogens from water. It consists in filling plastic bottles with water, and exposing them to solar radiation for several hours.

Advantages  Low costs  Easy to implement  Does not produce hazardous by-products  Effective against bacteria and viruses

Disadvantages  Suited for cleaning small quantities of water (2 L of water per person per day) (Wegelin, Canonica, Mechsner, & Fleischmann, 1994)  Dependent from weather and sun availability: it requires, to be effective, at least 500W/m2 for 5 h minimum

Ozonation

Ozone is a powerful oxidant product with a high disinfection capacity compared to chlorination for example. It can be added at different points in the water treatment system such as before sand filtration or activated carbon, or as a final disinfection Figure 15. Schematic representation of an ozonation step. process (Oram, 2016)

Advantages11  Removal of organic and inorganic matter  Removal of bacteria, viruses and micro-pollutants, such as pesticides  Odour and taste elimination

Disadvantages12  High costs (needs professional implementation)  Due to hazardous by-products, activated carbon is needed as a follow-up measure  Does not provide residual protection in the tank to prevent recontamination

11 (Lenntech.com, 2016) 12 (Lenntech.com, 2016; Oram, 2016)

Reverse osmosis

Traditionally used in desalination plants, the reverse osmosis (RO) process is also available for domestic water filtration. This process works by applying high pressure to untreated water through a membrane. All particles larger than 0.001 microns are removed and clean water is produced.

Advantages  Requires little space  Wide prism of effectiveness (bacteria, viruses, heavy metals etc.)

Disadvantages  Requires electricity to function  Removes contaminants with salts and minerals13: need for human health to remineralise the water with Ca, Na and Mg (Kozisek, 2005)  Need for maintenance (changing carbon filters, concern for membrane deterioration)  High costs

Ultraviolet radiation

Cleaning water through an ultraviolet (UV) treatment is an alternative to using any chemical product. After having filtered water, it is disinfected by placing it under UV light. A light of a certain wavelength will kill most bacteria. Its efficiency depends on water quality, intensity of the UV light and time of exposure under the light. UV radiation is often used as the last step, after filtration and reverse osmosis processes.

Advantages  Does not produce hazardous by-products  Effective against bacteria and viruses

Disadvantages  Requires electricity to function  Requires maintenance to remain effective  Does not remove chlorine, heavy metals, not volatile organic compounds

13 Some RO systems contain the function to reintroduce minerals in treated water. If not, they should be bought separately and handled manually.

Water storage

Even after treatment, water should be stored safely, otherwise it could be recontaminated. To such ends, a clean, watertight and protected tank is needed. The location of the container depends on available space. It may be built above surface or underground, and may be constructed as part of the building, or in a separate unit. The size of the reservoir depends on the water available for storage (size of the catchment area, average rainfall), the amount of water used and the expected duration of time without rainfall. Storage tanks can be built in multiple ways, depending on the material, shape and size. Cement-brick, metal, plastic and concrete are viable options.

It is often the largest item of expenditure in the water harvesting system (Khoury- Nolde, 2006), as it can represent up to 45-70% of the total cost (Li, Boyle, & Reynolds, 2010), but simple solutions of storage at the household level (e.g. the plastic containers used in De Ceuvel evoked earlier) are possible to lower the costs. In the Diamondiaal village, tanks will probably be built on-site by the population. Therefore the design of the tank must be suited to local conditions, including availability of materials, labour and costs (Sturm, Zimmermann, Schütz, Urban, & Hartung, 2009).

Quantitative estimation Various approaches can be used to calculate storage requirements: ➔ The minimum design capacity of the rainwater tank is based on the difference between the cumulative monthly rainfall supply and the cumulative monthly demand (Reijtenbagh, 2010; UNEP & Caribbean Environmental Health Institute, 2009). It reflects thus on the maximum cumulative supply and demand, minus the cumulative storage in the container by the end of the year. It is calculated by the following equation: 푽 = ([퐦퐢퐧(푺)] − 퐦퐚퐱(푺)) − ∑ 푺풄 푉 = minimum design capacity (m3) S = monthly rainwater storage (m3) Sc = cumulative monthly storage (m3)

➔ The simple method: here, the average annual water demand is considered based on the amount of people and the number of dry rainless days per year (UNEP & Caribbean Environmental Health Institute, 2009).

푽 = 푨 ⋅ (푳풂 ÷ ퟑퟔퟓ) 푉= storage requirement (L) 퐴 = annual water demand (L) 퐿푎 = longest average dry period (days)

Above-ground tanks

This type of reservoir is common for rainwater harvesting through roof collection.

Advantages14  Cheaper than an underground tank  Easy water extraction by tap  Cracks or leaks are easier to detect  Easier access for cleaning

Disadvantages15  Require more space  Require anchoring to the ground as it is subject to weather conditions (e.g. wind)

Underground tanks

Unless the building is designed for Domestic Rain Water Harvesting (DRWH), it is often necessary to develop the infrastructure separately. Water is stored in an underground cistern, and a pump is required to extract it. This type of reservoir is most common for groundwater. It should be preferably of a cylindrical or hemispherical shape to limit pressure exerted by the soil on the tank when it gets empty (Li et al., 2010; Thomas, 1998).

Advantages  Preventing penetration of light and algal growth  Keeps water at a cool temperature  Saves space (Abdulla & Al-Shareef, 2009).

Disadvantages  High costs (requires excavation)  Difficulty to monitor their condition as leaks or cracks are not visible  Water extraction is more difficult and requires a pump (Abdulla & Al-Shareef, 2009)  Potential pollution by groundwater from below or flooding from the top  Price and construction depend on the capacity of the soil to support the infrastructure.

14 (Abdulla & Al-Shareef, 2009; Li et al., 2010; UNEP & Caribbean Environmental Health Institute, 2009) 15 (Abdulla & Al-Shareef, 2009)

Food and water

One of the major aims of Diamondiaal future inhabitants is the production of their own food. Besides traditional farming, there are other options for producing food without the use of soil. Through hydroponics (cultivation of fruits and vegetables in a closed loop where water is always recycled), and aquaponics (a combination of fruits and vegetables cultivation and fish farming) there is an alternative to produce two main food resources: vegetable and fish. They are an important source of vitamins, minerals and proteins. Additionally, these two techniques are widely used as a way of teaching alternative agricultural techniques. It would be a nice initiative for Diamondiaal inhabitants to organize workshops in order to connect people with nature and new agricultural techniques. Water is an essential component for agriculture and crop production. Various techniques can be used in rainwater harvesting for irrigation purposes. Rainwater can be obtained from pools, rooftop and greenhouses. The systems to collect the rainwater can be a single barrel at the end of a downspout or multiple tanks hidden in the ground with many pumps (Sabota, 2009). For a more elaborate explanation of water catchment see section of water and human.

Hydroponics

Hydroponics system (see Figure 16) is the technique of growing agricultural crops without the use of soil. Soil is substituted with inert growing media, providing plant support, moisture and maintenance. The irrigation system is integrated with the media, providing nutrients for the plant (Somerville, Cohen, & Pantanella, 2014).

Figure 16. Simple hydroponics unit (Somerville et al., 2014)

Input Output

 Electricity  Fruits and vegetables  Water  Organic waste  Nutrients

Advantages16  Reduction of water usage  No soil is required  Recycling of nutrients

Disadvantages  Initial costs are quite high  Knowledge is necessary for building and maintaining the system.  By using shared nutrients, diseases and pest can spread  Not all plants are suitable for hydroponics

Aquaponics

Aquaponics (see Figure 17) is a vegetable production system, which integrates the production of plants without soil and aquaculture (Rakocy, 2012). Water from the fish tank runs through filters to the plants that grow on a medium, where after the water goes back into the fish tank. Now the water in the fish tank can be reused again, which completes the circle. The fish waste is removed from the water through a mechanical filter (removal of solid waste) and through a bio filter. The bio filter is essential for the conversion of ammonia to nitrate, which both can be used as a nutrient for plants (Somerville et al., 2014).

Figure 17. Small-scale aquaponics unit (Somerville et al., 2014).

16 (Bradford County Cooperative Extension Service, 2016)

Input Outputs

 Electricity  Fruit and vegetables

 Water  Organic waste

 Nutrients

Quantitative estimation 1000 L fish tank and growing space of 3 m2 of aquaponics units [1]are considered suitable for 2 households (Somerville et al., 2014). Considering Diamondiaal with 20 households, a 10,000 L fish tank and an area of 30 m2 is necessary.

Advantages17  Significant reduction of water usage  No soil is required  Minimum production of waste  Pest and diseases are better controlled due to the fact that there is no soil  Easy to implement and build  Fun for children to learn about sustainable concepts

Disadvantages  High costs  Knowledge of fish, bacteria and plant production is needed  Fish and plant requirements do not always match perfectly.  Not recommended in places where cultured fish and plants cannot meet their optimal temperature ranges.  Mistakes or accidents can cause collapse of system.  Daily maintenance of the system is necessary  The system needs electricity  Aquaponics will not provide enough for the community of Diamondiaal

17 (Somerville et al., 2014)

Human and Food

One of the wishes of Diamondiaal is to produce self-grown fruits and vegetables. Self-providing in terms of food would make use of individual’s talents and knowledge, and increase the general collaboration and group feeling. Considering the size of the population of Diamondiaal, the food production will be done on a large scale by some skilled individuals. Instead of traditional outdoor farming, greenhouses could be used to increase the output of food production. One way to reduce the area needed for food production is though vertical farming. Beside these large scale productions, each household could also make small contributions to the food production. Cold frames could be placed in every backyard to grow some crops, together with window frames in some windows to grow some small plants and herbs.

Circularity is not a new concept in nature. The output of one organism is the input for another organism and the other way around. An example would O2 that humans convert to CO2, and which is converted back to O2 by plants. Another example is composting human output, like human faeces and organic kitchen waste, which turns into nutrients for plants.

Several techniques will now be further explained that could contribute to the circularity of Diamondiaal in the connections between human and food.

Composting

Composting is the conversion of organic ‘waste’ by microbes and worms into fertilizer for plants. It is an aerobic process and for which water, air, and carbon- and nitrogen-rich materials are needed.

During this process, heat is generated by thermophilic microorganisms. The amount of heat depends on the size, the composition and moisture of the compost pile. This heat could be captured and used for the heating of a greenhouse or another building. This could be done by letting tubes with water run through the compost pile: cold water is pumped through the pile, where it is warmed up, and is pumped outside the pile again towards for example a greenhouse. Besides heat, CO2 is also produced within the compost pile. This CO2 could be very supportive for the growth of plants inside a greenhouse.

So composting could have different purposes: fertilizer for plants, heat generation, and improvement of the air composition in greenhouses by adding CO2 (Harland, 2014). Examples of organic ‘waste’ that could be used for composting are human faeces and organic kitchen waste.

Separated dry toilets

Separated dry toilets separate the faeces from the urine when it ends up in the toilet bowl. Removal of the liquid out of the solid mass, eliminates the odour and supports the composting process. The final dried product, that is rich in plant nutrients such as nitrogen, phosphorus and potassium, could be used for plant cultivation (Vinnerås & Jönsson, 2002). 18

Picture 7. A separated dry toilet18.

Quantitative estimation Normally, a human adult produces 100 to 250 grams of faeces per day of which 25 % is solid mass (Britannica, 2016). This would be around 40 grams (25 to 62.5 grams) of organic matter per person per day. For the 60 future inhabitants of Diamondiaal, this would be 2,400 grams of organic matter per day and 876 kilograms per year. If the daily visitors, estimation of 40 people per day, would be included in the faeces production, the total amount of organic matter would be 1,460 kilograms per year.

Advantages  Reduces water consumption and wastewater production  Recovery of the organic mass closes the nutrient loop  Eco friendly  No sewer is needed: off the grid

Disadvantages  Quite radical change in behaviour  Quite labour-intensive  Special cleaning products and toilet paper should be used

18 Retrieved from www.compostingtoiletsusa.com.

Organic kitchen waste

Organic kitchen waste, such as fruit and vegetable rests (peelings, kernels, etc.), eggshells and coffee residues are great substrates for the production of plant fertilizer. This green waste is protein rich which supports the microbes that are responsible for the breakdown Picture 8. Compost from kitchen process. Together with brown waste from the garden, waste19. which is full of carbon, the breakdown process could start since brown waste is the energy source of the break down microbes. Finally, enough water and air should be added to the pile, to optimize the composting process. 19

Quantitative estimation On average, one person produces 75 kg of organic kitchen and garden waste per year. For the 60 future inhabitants of Diamondiaal, this represents 4,500 kilogram per year. The speed of the composting process depends on several factors, e.g. the size and composition of the particles in the compost pile and whether they are in balance, the activity of the bacteria and what season it is. A pile of 1 to 1.5 m3 could be converted into compost in three months (“Composting in the Home Garden - Common Questions,” 2016), when it is regularly turned over to add oxygen.

Advantages  Low costs  Recreative  Great fertilizer due to minerals

Disadvantages  Several months are needed to turn the pile over before it is ready to be used  Possibility of disturbance by odours

19 Retrieved from www.sheknows.com.

Greenhouse (also glasshouse or hothouse)

A greenhouse is a structure, primarily of glass or clear plastic, in which temperature and humidity can be regulated for optimal cultivation and protection of plants. A greenhouse also allows the growth of certain plants that would not be able to grow in the Dutch climate, which would enlarge the variety of the

20 Picture 9. Example of a production. 20 greenhouse . The solar radiation passes through the transparent roof and walls and is absorbed by the earth and the air, which increases the temperature inside the greenhouse. This increased heat is trapped inside the greenhouse, because the transparent roof and walls do not transfer infrared radiation. Due to the closed structure of a greenhouse, the collected warmth is not able to escape via convection, which results in an increase of temperature. This effect is called the greenhouse effect.

Ventilation in greenhouses is needed to prevent some serious problems, such as inconsistent temperature and humidity during different seasons, accumulation of plant pathogens, and insufficient supply of fresh air for the process of photosynthesis (Baptista & Bailey, 1999).

In terms of heat, solely sunlight might not be most effective resource for optimal cultivation of crops in the Dutch climate. Therefore, external heating is an option. As will also be discussed later in this chapter, compost piles produce heat that could be used to heat up a greenhouse. Compost piles also add carbon dioxide in the air, which is favourable for the plants growing inside the greenhouse.

Inputs Outputs

★ Electricity ★ Heat

★ CO2 ★ O2 ★ Water ★ Fruits and vegetables ★ Nutrients ★ Organic waste

20 Retrieved from www.mnlga.org.

Quantitative estimation As is stated in the quantitative constraints, the size of the greenhouse needs to be around 2,400 m2 in order to produce enough daily fruits and vegetables for all 60 inhabitants.

The exact amount of water that is needed in greenhouses is dependent on a number of factors: the light intensity, which crops are grown, etc. Depending on these factors, the required amount of water in the greenhouse of 2,400 m2, is 960 – 2,880 m3 water per hectare per year (Beerling, 2013).

The exact amount of carbon dioxide (CO2) that is required for greenhouses, is also dependent on a number of factors such as which season it is, which crop is grown, the intensity of the ventilation, the level of lighting, etc. So depending on these 2 factors, the required amount of CO2 in the greenhouse of 2,400 m is 24 - 72 kg per hour.

In terms of electricity, a greenhouse consumes, but also produces electricity. In 2013 in the Netherlands, the average consumption was 50 kWh per square meter and the average production was 120 kW per m2. For a greenhouse of 2,400 m2, this would be 120,000 kWh and 288,000 kWh (Velden & Smit, 2014).

Advantages  Ultimate control leads to creating the perfect growing environment to optimize the cultivation of crops  Possible to produce non-indigenous plants, e.g. tropical fruits in the Netherlands, which leads to a large variety.  A greenhouse may be used as a heat source

Disadvantages  The constant maintenance is time consuming  High costs for water and energy on this scale

Vertical farming

Picture 10. Example of vertical farming21

Considering the fast growing human population, new methods are being developed to reduce the surface needed for food production. One of these methods is vertical farming. Vertical farming is, as the name suggests, farming in a vertical manner which could reduce the surface up to 12 times. It is an intensive way of farming for which advanced techniques are used, such as hydroponics and aeroponics. The world’s largest vertical farm is built in Newark, New Jersey. Here, a former steel factory of 6,210 m2 was transformed into a plant production farm (Cherian, 2016). In comparison with traditional outdoor farming, vertical farming has several advantages and disadvantages on which we will further elaborate in the following sections.

Vertical farms are located in greenhouse like buildings and mainly use the techniques of hydroponics or aeroponics. Hydroponics allow the growth of crops by using mineral nutrient solutions in water, so therefore no soil is needed. Due to the recycling of the water used in hydroponics, hydroponics use around 70 % less water compared to traditional outdoor farming. Aeroponics is another technique that could be used in vertical farming. It allows the growth of crops by using mineral nutrient air or mist, so therefore no soil is required and significant less water is needed22.

Due to highly controlled growing conditions, there is an increase of the year-round crop production. It also allows a reduction or even total abandonment of the use of chemical pesticides. These aspects of vertical farming make the process highly environmentally friendly.

Besides the many advantages of vertical farming, there are also some issues. The financial feasibility of vertical farming is not quite established yet. The amount of sunlight that is needed is still equal to that of traditional farming. The costs of lighting and heating could be so high that environmental benefits would not be predominant. Also if this power is originated from fossil fuels, environmental benefits of this agricultural method will be lost (Bareja, 2016; Despommier, 2014).

21 Retrieved from http://www.aginnovators.org.au/. 22 Aeroponics even consume around 70 % less water compared to hydroponics.

Inputs Outputs

★ Electricity ★ Heat

★ CO2 ★ O2 ★ Water ★ Fruits and vegetables ★ Nutrients ★ Organic waste

Quantitative estimation The concept of vertical farming is quite new and therefore no reliable numbers and data are available yet. The concept is somehow similar to the greenhouse: it is a form of farming within a transparent building with controlled environment to optimize the cultivation of crops.

Advantages  Significant less ground surface needed  Significant less water needed  Implemented in buildings  Closed loop due to the recycling of water

Disadvantages  Possibly high costs for energy: Light and heating  Advanced techniques are needed: Costly and difficult in use  Intensive way of farming: High monitoring is required

Window farming

Although the main food production will be done most effectively on a large scale, farming within a household would increase the spirit of living within nature and might be an opportunity for recreation. An example of farming within a house or a building is ‘window farming’.

Window farming is a gardening technique based on a hydroponic system. It is hung up in the inside of the window and allows year-round production of small plants like herbs. It makes use of natural sunlight and the warmth of the indoor environment. A water pump circulates the water that contains plant nutrition from a small water basin on the bottom of the system to a small water basin in the top of the system. From there, it drips into the first plants down to the second row of plants etc. In this way, all plants are provided with water and 23 Picture 11. Plants grown in nutrients. a window farming 23 system .

Quantitative estimation If every household would have a window farm of 1 m2 and we take the estimation of 20 households in Diamondiaal, window farming would be on a scale of 20 m2. 1 m2 could harvest 6 small plants, so 20 m2 could harvest 120 small plants. It takes basil seeds for example 6 to 8 weeks to grow into a plant size that could be ready for harvest (Palomo, 2016). Besides basil, also bay, chervil, oregano, parsley, rosemary and thyme could be grown indoors in a window farm. This could be enough to support the herbal use of the future inhabitant of Diamondiaal.

Advantages  Nice small experiment for inexperienced people  Easy to setup and maintain  Opportunity for educative purposes Disadvantages  Very small scale  Does not add to the circularity of the community

23 Retrieved from our.windowfarms.org.

Cold frame

Another example of a small scale farming is by using a cold frame. Every household could have one in its garden, to optimize home grown crops.

A cold frame is a small greenhouse, basically a box placed over the plants with a transparent top, which passively collects the solar energy and protects the plants from adverse weather. Water supply should be monitored and applied if necessary. Some vegetables that could grow nicely in a cold frame are carrots, leeks, radishes, spinach, lettuces and arugula (Weiss, 2016). 24

Picture 12. Examples of cold frames24.

Quantitative estimation Every household could have a cold frame of, on average, 2 m2, which means that Diamondiaal could have 40 m2 of farming within a cold frame. Especially salad greens and root vegetables are productive inside a cold frame. Although the harvest of a cold frame is not enough to sustain a household, it is a great method to contribute to the total food production with home-grown food (Weiss, 2016).

Advantages  Nice small experiment for beginners with gardening  Easy to setup  Protects crops from adverse weather

Disadvantages  Small scale  Constant maintenance needed

24 Retrieved from http://www.sunset.com/.

Energy and Human

Households require a certain quantity of energy for space heating and hot water. On average, this will amount to 319,967 kWh per year for 20 households expected in Diamondiaal. This amount can be achieved with several different mechanisms, which will be further elaborated upon in this section. Flows that will be discussed here are potential sources of energy that can be obtained by the use of human waste and also other energy sources that are required for the households of Diamondiaal. Systems that are going to be discussed are: solar thermal energy, solar panels, wind energy, anaerobic digestion, combined heat and power installation, heat pump,

woodchip burner, biomass gasification and biomass furnace for recovering CO2 from flue gases.

There are diverse techniques for actively harvesting sun energy. Apart from collecting sun with a solar thermal collector for heat, sunlight can also be used to produce electricity. In this section, both will be discussed.

Solar energy strongly depends on the seasons, the place on earth and the radiation field. The atmosphere has an influence on the amount of solar radiation that arrives on earth. Due to different weather circumstances, the amount of solar radiation can be reduced (see Figure 18). Clouds reflect a part of the sunlight and another part get absorbed by the atmosphere. Also a part of sunlight gets reflected by the soil. Only a part of the sunlight will hit the earth directly. In the Netherlands, diffuse radiation is on average 50% (mostly in summer and winter). This is an important factor to take into account, because there are solar systems that only work with direct irradiation.

The intensity of the irradiation is expressed in Watt per square meter (W/m2). There can be quite some fluctuations within this intensity. On a cloudy day, the intensity can be 50 W/m2 and on a clear day is can be 1,000 W/m2. Energy is the power during a certain time period expressed as Watt hour Figure 18. Global irradiation in the Netherlands on a (Wh). The daily maximum in the 2 yearly basis in kWh/m (Viessmann Werke, 2008). 2 Netherlands in summer is 5 kWh/m and on a sunny winter day 2 kWh/m2. The

averages on a yearly basis in the Netherlands can be seen in Figure 8. In this image, it becomes clear that there are some differences between coastal areas and more inland areas.

Solar thermal energy

A well working solar heating system should not only depend on a sun collector, but should work in a system with several interacting components (bivalent system). Especially in the winter, you cannot depend solely on solar heating. An additional component can be coupled to the system that works on gas, and makes sure there is always warm water in the system. Solar heating can reduce fuel consumption by preheating the water that runs through this system. Error! Reference source not found.19 shows a bivalent system, which contains a sun collector and a central heating system. These systems are based on one household but maybe it could also be implemented at the community level. It was hard to find examples of this in literature so everything explained further in the text is based on systems for one household.

The efficiency of solar heating depends on several components that are integrated in the system. A part of the solar energy will be lost due to reflection and absorption of the glass cover. The proportion of irradiation on the collector and the part that gets transferred to heat is called the optical efficiency. Also a part of the energy will be lost due to thermal conduction. After the subtraction of these losses, the collector efficiency remains and explains the quality of the collector. When using the maximum irradiation of 1,000 W/m2 and an optical efficiency of 80 %, then the collector 2 Figure 19. Bivalent system with a sun collector and a central can deliver 0.8 kW/m (Viessmann heating system (Viessmann Werke, 2008) Werke, 2008). In reality, this will almost never be achieved. Most of the designers that make these collector system use 600 W/m2 as an average number. This number gets closer to reality, but due to fluctuations in the intensity of irradiation, this number will not always be the same.

Another way to calculate the efficiency of the collector system is by means of solar coverage. This indicates the percentage of the intended use that should be generated by solar heating. If the solar coverage is higher, other energy sources can

51 be saved. The total amount needed also depends on the size and isolation of your building. On average for a single family home, the solar coverage is 50-60 % (Viessmann Werke, 2008).

Instead of water, there are also collector systems that have antifreeze as a medium. An advantage of this system is that the system does not freeze in winter and keeps functioning well. This system also protects against corrosion, because no oxygen is present. These systems do need an expansion tank to capture the expansion of the medium when it heats up. This is the most popular system in the mid- and west of Europe.

Another system used for solar heating is a system under pressure with thermal frost protection. The only difference of this system with the previous one is that the medium contains water instead of antifreeze. To overcome water freezing in winter, heated water gets transported from the boiler to the collector. Due to the heating of this collector, some energy will get lost in winter. These energy losses strongly depend on the outside temperature. On average, you can count on 10 % of the yield of the collector.

A final system that is used for solar heating, is a drainage system. This system drains the medium when the installation is turned off. This medium is captured in a tank. Most of the times, the medium is with water. In winter, it is not possible to use such a system.

Input Output  Irradiance  Heat

Quantitative estimation Calculating the exact amount of energy this system can produce is not easy. Therefore, it was needed to make a very rough estimation. It was mentioned in the section of quantitative constraints that 1,000 kWh/m2 is available irradiance on a yearly basis. If we know the efficiency of a solar heating system, then we could calculate the amount that will be produced on average. We mentioned earlier that 80% efficiency gave 0.8 kW/m2, but these figures are not based on realistic conditions. In reality, we should consider a lower efficiency of 60 % giving 0.6 kW/m2.

Using 60 % as efficiency and 1000 kWh/m2 irradiance on a yearly basis would give 0.6 * 1000 = 600 kWh/m2 on a yearly basis.

Within Diamondiaal, 20 households need 319,967 kWh per year (see earlier calculations in the section of Quantitative Constraints). Because solar heating is always implemented in a bivalent system, it accounts for 50-60 % coverage of the required energy which is stated in the text. The other 40-50 % of the energy should

52 be complemented by another source of energy. This would mean that 20 households would need 159,983.5 kWh from solar heating per year when choosing 50 % as coverage.

159,983.5/600 = 266.64 m2 of land should be covered with panels to cover this amount of energy. This is a little bit more than 1 % of the total land that is available for Diamondiaal.

Advantages  Solar heating reduces the fuel consumption by preheating the medium.  A system with antifreeze or a system under pressure with thermal frost protection can both be used in all seasons.  Solar heating is a renewable energy and thus reducing waste streams.  Maintenance is very low  Solar heating is relatively cheap. For € 2,000,- you can have all the elements needed for one household25.  This technology doesn’t take much space (266.64 m2).

Disadvantages  Solar heating needs to be combined with another source of energy. Solar heating alone is not enough for the amount of energy that is required in a household.  A drainage system cannot be used in winter  Antifreeze sometimes needs to be replenished

Solar panels for electricity

Another renewable energy source is one in which photovoltaics (PV) is used for electricity. Photovoltaics converts solar energy into electricity. At first, solar cells were based on semiconductors and after some time polycrystalline Si and thin-film solar cell technologies were developed (Razykov et al., 2011).

A PV-panel consists of multiple little solar cells that are connected to each other. Every solar cells has a thin layer of semi-conductive material in which a voltage difference is created due to sunlight. There are several types of solar cells including monocrystalline, polycrystalline and amorphous solar cells. These different structures give different efficiency and longevity. The efficiency determines which part of the irradiated solar energy is actually delivered in the form of electrical energy (Ternary.eu, 2016).

25 We used here as a reference a 200 L solar thermal collecting set suitable for a household of 5-6 persons (Techniq-Energy.com, 2016)

There are several components needed for this system (see Figure 20). These include a battery, a charge controller and an inverter.

Figure 20. Various components needed for a functioning system (Leonics, 2016).

The power of solar panels is expressed in watt-peak (Wp). The panel delivers a voltage, which will be translated with a converter to 220 Volts. In the Netherlands, an optimally located solar panel with 100 Wp delivers about 80 kWh on a yearly basis (Ternary.eu, 2016).

Input Output  Irradiance  Electricity

Quantitative estimation With this system, we use a rough estimation to calculate the amount of energy that it can produce. Because 72,780 kWh per year are needed for 20 households, it is possible to calculate the amount of solar panels that are needed to obtain enough electricity. It is known that one solar panel of 100 Wp delivers about 80 kWh on a yearly basis. This means that 72,780/80 = 910 solar panels are needed to cover the electricity demand of Diamondiaal.

Advantages26  Possibility for storage, because the energy yield can be stored, it is possible to use solar energy even when there is less irradiation as long as a high quality battery is used.  Renewable source of energy, which reduces waste.  The expenses at the start can be earned back in 25 years.

Disadvantages  It takes a great amount of solar panels to comply the energy demand of Diamondiaal.  Implementing 910 solar panels could be very expensive when purchasing them. To be able to store energy in batteries, it is important to have high quality batteries. These can be expensive.  The panels need to be placed in a proper way to obtain the maximum capacity. This could be difficult on the houses for Diamondiaal because the design at this point contains round rooftops. A separate field has to be cleared for these panels.

26 (OfferteAdviseur.nl, 2016)

Wind power

In the Netherlands wind turbines currently account for over 5.2 billion kWh of energy per year (NWEA, 2016). The working principle of a wind turbine is the conversion of kinetic energy, from wind to electricity. This is achieved by powering a generator with the shaft connected to the turbine blades. 27

Size is a key characteristic when it comes to wind turbines. As a general rule, one can assume that higher turbines with larger rotor diameters produce more energy (Beurskens & van Kuik, 2004). Modern, 'big' wind turbines have a pole height of 80 - 100 metres and a power of 2 - 3 MW, which results in an energy production of about 6.5 million kWh every year (NWEA, 2016). This scale of production could power everything in Diamondiaal 50 times over.

Figure 21. Working principle of a wind turbine27.

However, Inspiratie Inc. has repeatedly stated that they would not want to live too close to such a wind turbine. On the other hand, wind turbines of a slightly smaller height are already present very near to the Diamondiaal building site. It could be an idea to approach the company that owns these wind turbines and see if a collaboration is possible.

Progress is being made with smaller scale designs. These systems, also associated with microgeneration, have a pole height of 4-18 metres and a power of 0.5 - 6 kWh (Cace, 2010). Small wind turbines are divided into two types. Horizontal axis turbines (HAT) and vertical axis turbines (VAT). This distinction is based on the orientation of the axis. Picture 13 below shows an example of each type.

27 Retrieved from http://www.tutorvista.com/content/science/science-ii/sources-energy/wind- energy.php

Picture 13. Left: a horizontal axis turbine 'Eclectic'. Right: vertical axis turbine 'Quiet Revolution' (Cace, 2010).

Input Output  Wind  Electricity

Quantitative estimation Because industrial scale wind turbines have a power and energy production that exceeds the demand of Diamondiaal by far, a small wind turbine is considered here. The Netherlands Enterprise Agency (RVO) executed quite an extensive analysis on available small wind turbines. One of those is the Donqi. Using data and formulas from RVO, the following calculations can be done for Diamondiaal (Cace, 2010).

The Donqi has a power of 1.75 kW and rotor area of 1.77 m2. It is assumed that it produces 180 kWh/m2 of rotor area per year. This amounts to the following annual production per Donqi.

퐸푑표푛푞푖 = 푅표푡표푟 푎푟푒푎 ∗ 푃푟표푑푢푐푡𝑖표푛 푝푒푟 푟표푡표푟 푎푟푒푎 = 1.77 ∗ 180 = 318.6 푘푊ℎ 푝푒푟 푦푒푎푟

If a total of 30 units would be installed (1 for every home and 10 additional units placed on other facilities within Diamondiaal), then the total yearly production would be:

퐸푑표푛푞푖 푡표푡푎푙 = 30 ∗ 318.6 = 9558 푘푊ℎ 푝푒푟 푦푒푎푟

This adds up to about 13 % of total household electricity demand. We chose to illustrate the Donqi because of its aesthetics (unlikely to cause nuisance) and the costs per unit (€ 6500,-).

Advantages → Oosterwold is a suitable location for wind turbines small and big → Subsidy (EIA) is available → Installation of small wind turbines can be done by the residents with the help of some expertise

Disadvantages → Small wind turbines range from 2,000 – 30,000 euro. A higher investment within this range will yield higher energy production, but it is unlikely this will cover more than 50% of Diamondiaal energy demand. → Wind turbines can meet social resistance. People have shown to indicate scepticism regarding safety and also complained about noise, moving shadows from turbine blades, flickering light and visual pollution.

Working examples A detailed overview of small wind turbines can be found in the guide by RVO, practical application of mini-wind turbines (Cace, 2010). This overview also includes approximate costs. One interesting option is the 'Eclectic' wind turbine which costs about € 200028. The installation can be done as a ‘do-it-yourself’ project as online guides and videos are available. The limited energy production is something to keep in mind. Another approach could be to 'invest'. There is an example of a wind turbine park at Zeewolde, which is one of the multiple projects where local residents and companies are collaborating with big companies. The construction of 200 industrial size wind turbines in Zeewolde is financed this way (hieropgewekt.nl, 2016).

Anaerobic digester small-scale

Anaerobic digestion is a process where microorganisms break down organic materials in absence of oxygen and thereafter converts these into biogas. An anaerobic digester (see Figure 22) is a sealed compartment that simplifies the degradation through anaerobic digestion of black-water, sludge and biodegradable waste (animal manure, kitchen and garden waste). The anaerobic digester is frequently installed for co-digestion of animal manure and toilet waste at the community and household level (Eawag & Spuhler, 2016). The final product in anaerobic digestion is the production of biogas, which can be used for heating and cooking. The digestate that is left (nutrient rich sludge) can be used as fertilizer for agricultural purposes (Lukehurst et al., 2010). The biogas reactor could be coupled to private and public toilets with an extra access point for organic material (Lukehurst, Frost, & Seadi, 2010). For a single family the reactor can be made out of

28 This indication of price is retrieved from http://www.energyonthehook.com/Eclectic-Energy-D400- Wind-Generator-p/ecld400.htm.

58 a plastic container and the size can vary between 1,000 L for a single family to 10,000 L for a public toilet (Eawag & Spuhler, 2016).

Figure 22. Example of anaerobic digester (Eawag & Spuhler, 2016)

Input (Cook, 2010) Output  Organic waste  Biogas  Nutrients

Quantitative estimation In Diamondaal, there are 60 inhabitants and including the central community house that is also available for visitors, an attendance of 150 people has to be taken into account. It is important to note the amount of organic kitchen waste is estimated for inhabitants of Diamondaal only (60 people). The amount of faeces are estimated for Diamondaal inhabitants (60 people) and the possible visitors (90 people) for a total of 150 people.

Assuming that one person excretes 0.35 kg of faeces per day and produces 0.25 kg of organic kitchen waste (Eawag & Spuhler, 2016; Vögeli & Lohri, 2009), the total amount of organic waste in Diamondaal would amount to:

푇표푡푎푙 표푟푔푎푛𝑖푐 푤푎푠푡푒 = [(0.35 ∗ 150) + (0.25 ∗ 60)] ∗ 365 = 24,638 푘푔 푝푒푟 푦푒푎푟

The amount of biogas produced for 1 kg of faeces is 60 L. The amount of biogas produced for 1 kg of organic kitchen waste is 100 L (Eawag & Spuhler, 2016).

Therefore, the total biogas produced would amount to:

푇표푡푎푙 푏𝑖표푔푎푠 푝푟표푑푢푐푒푑 = (0.35 ∗ 150 ∗ 365 ∗ 60) + (0.25 ∗ 60 ∗ 365 ∗ 100) = 1700 푚3 푝푒푟 푦푒푎푟

Assuming that 1m3 of biogas equals 6 kWh (Eawag & Spuhler, 2016), then the energy production amounts to:

퐸푛푒푟푔푦 푝푟표푑푢푐푡𝑖표푛 𝑖푛 퐷𝑖푎푚표푛푑푎푎푙 = 1700 ∗ 6 = 10,200 푘푊ℎ 푝푒푟 푦푒푎푟

This represents roughly 3 % of total household heat demand.

Advantages29  Generation of renewable energy  Small land area required (most of the structure can be built underground)  No electrical energy required  Combined treatment of animal, human and solid organic waste  Conservation of nutrients  Long service life  Low operating costs  Conservation of nutrients

Disadvantages  Requires expert design and skilled construction  Substrates need to contain high amounts of organic matter for biogas production  Incomplete pathogen removal, the digestate might require further treatment  Limited gas production below 15 °C  Because the structure is underground it could cause problems when there is a soil subsidence expected of 0.8 meters in the upcoming 50 years  Risk of getting exposed to pathogens

29 (Eawag & Spuhler, 2016)

Combined heat and power (CHP)

Also referred to as cogeneration, CHPs produce electricity by coupling an engine to a generator. The heat produced by the engine is not wasted, but put to a new use (see Figure 23). A frequently used type is an installation in which the engine is powered with gas (Masters, 2013).

Figure 23. Schematic representation of a CHP system. Source: TSF Engineering. Input Output  Bio fuel  Electricity  Heat

 CO2

Quantitative estimation If this system would be implemented, 2 figures are important: the capacity and the available fuel. Sustainable fuel can only come from biogas-, biofuel production or wood waste within Diamondiaal, and these sources are not abundant. The biogas Diamondiaal could produce was found to be approximately 1700 m3 (see Anaerobic digester earlier). This equalled to 10,200 kWh. If a CHP is considered with an electricity efficiency of 30% and a heating efficiency of 50 % (Clark, 2013; Masters, 2013):

퐸푙푒푐푡푟𝑖푐𝑖푡푦 푝푟표푑푢푐푒푑 = 10200 ∗ 0.3 = 3060 푘푊ℎ 퐻푒푎푡𝑖푛푔 푝푟표푑푢푐푒푑 = 10200 ∗ 0.5 = 5100 푘푊ℎ

This would only cover roughly 4 % of yearly household electricity demand and only 1.5 % of the household heat demand. Thus, fuel is a limiting factor. Based on the Quantitative Constraints and a detailed research on usage (Boedijn, de Jonge, de Jonge, van den Doel, & Baas, 2013), a heat load requirement during the

61 day of 110 kW seems reasonable for Diamondiaal. An electricity requirement of 35 kW is also assumed. Both requirements only take the households into account. If the capacity of the CHP is based on the electricity demand, then the input of fuel is the following:

퐸푙푒푐푡푟푖푐푖푡푦 표푢푡푝푢푡 35 퐹푢푒푙 𝑖푛푝푢푡 = = ≈ 117 푘푊 퐸푙푒푐푡푟푖푐푖푡푦 푒푓푓푖푐푖푒푛푐푦 0.30

If only 1700 m3 of biogas is available per year then the CHP could only run for:

10200 푘푊ℎ ≈ 87 ℎ표푢푟푠 117 푘푊

Advantages → Electricity and heat are outputs of this technique, and both could have multiple implementations. → When the technique is installed, there is not much action further required. This makes the operating of the engine easy.

Disadvantages → Investment is high for a CHP unit suited for the whole of Diamondiaal. → Installation can only be done by an expert. → The technology is only sustainable when bio fuels are used as a resource.

Heat pump The past decade the 'domestic heat pump' has emerged as a sustainable alternative for the heating demand of households. Due to the growing efficiency of new systems, heat pumps are now used to heat, cool and provide hot water for homes up to 250 m2 (Silberstein, 2003). A typical heat pump makes use of a refrigerant and a vapour compression cycle (see Figure 24). To complete this cycle the heat pump uses electricity to run the compressor. 30

Figure 24. Vapour compression cycle4: 1) condenser, 2) expansion valve, 3) evaporator, 4) compressor30.

There are several main types of heat pumps (Boedijn et al., 2013): → Air-to-air heat pumps extract energy from the outside air and give it off to the inside air. This type can only be used for heating. → Air-to-water heat pumps give off the extracted energy to water which can then be used for both heating and hot water. → Ground-to-air heat pumps extract energy from the ground and give it off to the inside air. → Ground-to-water give of the energy to water. → Water-to-water heat pumps extract energy from a body of water. This can be a natural source, for instance a lake, but it can also be a reservoir, tank or man-made aquifer.

There are options for Diamondiaal to make use of this technology, especially in combination with other systems, such as a water buffer. Design choices with respect to scale (i.e. individual household or centralised system) and type are key (Hansen, 2016; Wotech, 2016). Some of the qualitative constraints should also be considered. This is mostly related to the soil conditions at Oosterwold. Heat pump systems that extract energy from the ground, which are widely used in the Netherlands (Boedijn et al., 2013), might run into complications. These complications include installation and municipal regulations.

30 Retrieved from https://en.wikipedia.org/wiki/Heat_pump#/media/File:Heatpump2.svg.

Input Output

 Electricity  Heat

 Heat source

Quantitative estimation Depending on the type of heat pump, the average installed heating capacity ranges from 3.5 kW (air-to-air heat pumps) to 9 kW (ground source- and air-to-water heat pumps) (Laitinen, Tuominen, & Holopainen, 2014). The following calculation, introduced by Eurostat, shows what the annual heating energy production is.

푄푢푠푎푏푙푒 = 푄푖푛푠푡푎푙푙푒푑 ∗ 푄푢푠푎푏푙푒 푓푎푐푡표푟

2 It is assumed that a household of 4 persons, in a 120 m house, needs an installed capacity of 8 kW to meet heating demand year round (Boedijn et al., 2013).

Considering the climate in the Netherlands, a Qusable factor of 2000 (table 6) is assumed.

푄푢푠푎푏푙푒 = 8 ∗ 2000 = 16000 푘푊ℎ 푝푒푟 푦푒푎푟

For the 20 households in Diamondiaal, this would come down to a heat production of 320,000 kWh. Although this is an overestimation, since not all households consist of 4 persons, it does show that indeed the quantitative constraint for heating (see p.21) is met. Therefore we conclude the following:

Installed heat pump capacity to meet total heating demand is about 160 kW. Assuming an SPF of 3.2, the renewable energy production for Diamondiaal households is the following. 1 퐸 = 푄 ∗ (1 − ) = 320,000 ∗ 0.6975 = 220,000 푘푊ℎ 푝푒푟 푦푒푎푟 푟푒푠 푢푠푎푏푙푒 푆푃퐹

Table 6. SPF and Qusable factor values suggested by Eurostat. Source: Eurostat.

Advantages → Suitable for integration with other technologies. (Water buffer as a heat source and the system diversifies electricity use.) → Low maintenance costs and a lifespan of about 15 years. → Large range of possible implementations of which at least one might be feasible.

Disadvantages → High investment. This may be mitigated by installing large scale systems instead of a system for each household. → Installation and operating requires expertise and cannot be executed by the Diamondiaal residents. Soil conditions in Oosterwold may restrict the use of ground source heat pumps. → Systems can cause some noise.

Woodchip burners

Although burning wood is not new, wood-chips burners are gaining popularity, as wood provides a source of energy for heating and appealing for people who want to be less dependent on other sources of energy. The biomass used in these systems, chipped wood, is usually a by-product of the sawmilling industry, but any type of wood pellets, briquettes or cubes can be used.

Table 7. Comparison of energy contained in various types of fuels. MC = Moisture Content (Wood Fuel South West Advice Service, 2016)

Wood is an external input that shall be stored before entering the heating system. Depending on the quantity stocked and available space, choice can be made between underground storage, silos or in open air under a covered shed. Because the transfer of the fuel is essential in ensuring a proper functioning of the heating system, the source of fuel should be close to the combustion centre. Table 8 below

65 summarizes the suitability of each of these storage solutions (Hodsman, 2004; Wood Fuel South West Advice Service, 2016).

Table 8. Review of fuel storage options.

Type Advantages Disadvantages

Underground storage Easy fuel delivery Expensive for small-scale systems. Local Diamondiaal constraints of soil subsidence and the flooding risks.

Silo Suitable when limited space available

Open air under shed Easy fuel delivery Manual transfer of fuel to burner Cheapest option

Biomass boiler systems can be automated (fuel is then directly fed by auger or hydraulic feeds) or not. Fuel is brought into the combustion chamber, where it produces hot gases and water that go through a heat exchanger before reaching the storage tank. From there, it is conducted to the heating circuit, which are traditionally radiators (Wood Fuel South West Advice Service, 2016).

Figure 25. Different components of a domestic biomass burning system31.

Input Output

 Bio fuel  Heat

 CO2

31 Retrieved from http://www.greenmatch.co.uk/blog/2015/02/pros-and-cons-of-wood-pellet-boiler.

Quantitative estimation Several possibilities of energy conversion exist. These systems can be used only for heating, but also for combined heat and power, boiler or stove. This choice determines the amount of biomass required. To estimate it, we convert the heating demand into biomass quantities. Table 7 above provides energy densities to compare between biomass fuels. It is also important to know the energy efficiency of the boiler used and take it into consideration before doing calculations (Wood Fuel South West Advice Service, 2016).

For Diamondiaal, our annual heating demand is 319,967.5 kWh. When considering a wood boiler 90 % efficient, we have 319,967.5 ÷90 % = 355,519.4 kWh. This is the amount of energy that needs to be brought into the boiler. Table 9 below summarizes our findings.

Table 9. Amount of biomass needed for household heating in the Diamondiaal village.

Type of biomass fuel Required amount (in ton)

Wood chip (at 30% MC) 118

Log wood (20% air died stacked wood) 85

Wood pellet 71

Advantages  Applicable at various scales  Easy to implement

 Potential for reusing CO2 in greenhouse systems

Disadvantages  Requires continuous operation to function at its highest efficiency  Requires regular maintenance and visual control

Biomass gasification Recently, technological developments have been investigated to optimise the heat and power generation capacity of biomass. This is done by biomass gasification, i.e. a thermo-chemical process used to convert carbon-based materials into syngas32. One of the instruments used to operate gasification is the down-draft gasifying reactor, presented in the Figure 26 below.

Figure 26. Schematic representation of a down-draft gasifier with the various processes involved (after Lefsrud, Madadian, & Roy, 2016; Madadian, Lefsrud, Lee, & Roy, 2014) .

Input Output

 Bio fuel  Heat

 CO2  CO

 H2

Quantitative estimation With this system, 1 kg of biomass would produce 2 m3 of gas, the equivalent of 0.75 kWh (Lefsrud et al., 2016). This means for Diamondiaal, with an annual heating demand for the household equal to 319,967.5 kWh, that 426,623 kg of biomass are needed to satisfy the demand.

This large figure should be put into perspective relating to the parameters used in the Qualitative Constraints, where the annual heating demand comprises also heating for water. It is then a very large estimation of energy needs.

32 Syngas combines carbon monoxide (CO) with hydrogen (H2) and low quantities of other hydrocarbons.

As CO2 is a valuable resource produced during the burning process, we offer to use it in the greenhouse system. Indeed, CO2 fertilisation can increase the growth rate in greenhouses by 15-30 % (Noren, 2002). The increasing popularity of biomass burners consists in an important source of CO2 for greenhouses. Using the CO2 output from the burning process to feed food production systems appears to be a relevant option for the Diamondiaal community.

Some techniques are in development, such as the one presented in the literature and described below, while some might be more simple and easier to tailor to the Diamondiaal context.

Biomass furnace for recovering CO2 from flue gases Roy, Lefsrud, Orsat, and Filion (2014) describe the example of an improved biomass furnace to recover the heat and CO2 produced in a wood pellet stove and inject them in a greenhouse. To such ends, they built a flue gas purification system in the chimney of the furnace. This purification system consist of an air filter, two heating components and a catalytic converter. The filter is in charge of removing particulates present in the flue gas (gas resulting from combustion processes), while heating elements and the catalyser make hazardous gases less toxic.

Figure 27. Prototype and description of the purification process components (Roy et al., 2014).

Water and Energy

A first glance at the characteristics of Diamondiaal tells us that some sustainable options, which make use of water, can be ruled out. The geographical location is not suited for wave- and tidal energy as well as hydroelectricity. However, water can play a key role in the storage of energy.

Buffers For Diamondiaal, water can be used as a storage medium in their search for sustainability. If renewable energy would be used, then short term- and long term buffers are both options to consider in order to increase energy supply consistency. Although there exist many designs, a short term buffer, also referred to as tank buffer, is often no more than a tank and some coiled piping. In Figure 28 some examples are shown. The energy storage capacity and retention time for short term buffers is somewhere between a day to week.

Figure 28. Tank buffer types. Source: http://www.rvr.ie/

Long term buffers, also referred to as seasonal thermal energy storage (Novo, Bayon, & Castro-Fresno, 2010), have a much higher capacity. These systems store energy over a period of months. Underground storage systems which can be considered for Diamondiaal are aquifer- and borehole systems (Paksoy, Snijders, & Stiles, 2009a, 2009b). Figure 29 illustrates how heat is stored in a body of water in the 'basement' of a greenhouse.

Figure 29. Greenhouse basement buffer. 71

Quantitative estimation The following calculation (van ’t Ooster, 2016)is used to get an estimate on how big a tank must be to supply heating for all Diamondiaal households for a day.

퐸 퐸 = 푉 ∗ (푐)푤 ∗ 훥푇 푉 = (푐)푤 ∗ 훥푇

Assuming that ΔT is 30 degrees (Molz, Parr, Andersen, Lucido, & Warman, 1979) and daily demand is 1400 kWh:

1400 ∗ 3600 (푘퐽) 푉 = ≈ 40 푚3 4186 (푘퐽 푚−3퐾−1) ∗ 30(°퐶)

Thus a tank capacity of 40,000 litres would be needed. This can also be divided over multiple tanks. However, if heat demand would be higher because of the community centre and other activities in Diamondiaal (i.e. restaurant, production of pottery/ceramics, water treatment and greenhouses), then a long term buffer can be considered.

Working examples Examples of existing domestic systems that could be introduced to Diamondiaal are those of KlimaRain Solutions and SolarFreezer. KlimaRain in corporation with EFraRain developed a system that stores rainwater in bags, placed in the basement. This body of water functions as the energy buffer. With their pilot system they managed to reduce yearly gas usage by 1,667 m3, which covered 48% of total heating demand (space heating and hot water). They relied on a storage capacity of 18,000 litres. The pilot system was built into a corner house with an area of 200 m2 and housed 5 persons. With the help of subsidy the investment amounted to €12,400 (van Bergen, 2011). The start-up company SolarFreezer has developed a system that utilises the energy which is released when water transitions to ice. Also in this system water is stored in bags, placed in the basement of the house. The capacity of their products ranges from a single household to multiple houses. The SolarFreezer should be able to completely replace gas usage (>3,000 m3) (Dekker, 2016; SolarFreezer, 2016).

Advantages → Highly applicable, because a buffer system can be connected to almost any type of other process that produces energy. Effectively, this means that a buffer can function as a heat sink for the whole of Diamondiaal → Low cost, because of low tech systems and subsidy is available for high tech systems. → High effectiveness, because buffer systems can save up to 50% of energy use with respect to heating demand (space heating and hot water). → High implementation, because most of the labour for installation (i.e. digging and drainage) could be subcontracted to the Diamondiaal residents.

Disadvantages → High costs, due to large scale and long term buffer systems require high investment. → Large scale, long term buffer systems rely on specific underground conditions. Some can only be implemented in the initial construction phase. → The aesthetics of above ground systems are not appreciated and this will have to be mitigated.

Heat Exchangers

The concept of a heat exchanger is to transfer energy, in the form of heat, from one liquid to another (see Figure 30). The concept has many designs and is implemented in diverse applications. Any process that produces heat, has a potential of using that heat. The aim of using heat exchangers in a sustainable context is to harness heat from processes where otherwise this energy would go to waste. Heat exchangers can be used in Diamondiaal at the household- and operating system level. One feasible example is the wastewater flow from showering. The runoff water from a shower is warm enough to pre-heat cold water. It will then cost less energy to heat the pre-heated water to the desired temperature. A company called EcoDrain has developed an integrated system to deal with shower water runoff. Their system saves 33 % on energy for heating shower water (“Ecodrain,” 2016). The same working principle can be used at large scale processes within Diamondiaal. For instance composting systems, digesters, wood chip burners etc.

Figure 30. Working principle of a heat exchanger. Source: Precision Graphics. 73

Advantages → Low costs, because of low maintenance and labour → Easy implementation, heat exchangers can be a product for DIY projects if appropriate expertise and guidance is available.

Disadvantages → The costs for individual household systems may be too high compared to the cumulative contribution to energy saving. → Large scale systems often need separate implementation space (additional 'industrial' building).

Microbial fuel cells

Microbial fuel cells (MFC) are capable of converting organic waste that is present in wastewater or livestock manure into electricity. Several factors influence the production of electricity by MFC’s such as substrate, electrode materials, conductivity of the solution, reactor design and so on. Waste streams that can be used as a substrate for MFC are livestock manure and wastewater. The maximum value that is reported for MFC is 3.9 W/m2. This power is obtained with the strain of Geobacter sulfurreducens KN400 with acetate substrate in a 2-chamber MFC (Pant et al., 2011; Yi, Nevin, Kim, & Franks, 2009). A two chamber design is most commonly used which consist of two chambers connected by a tube. This tube contains a cation exchange membrane (Logan & Hamelers, 2006).

Figure 31. General overview of bioelectrochemical systems. On the left an overview of the microbial fuel cells are shown (Pant et al., 2011).

At the moment, some initiatives have started up pilots with MFC at wastewater treatments but this technique is not commercially available yet. Wastewater treatment sites use MFC, because it can be used to purify water and simultaneously generate electricity. Specific pollutants that can be removed from water are: nitrate, sulphur- based pollutants and Cr6+.

Despite that it is not commercially available, this technique is worthwhile mentioning because in the future there will probably be great developments regarding this technique. There is a rapid growth in the research of MFC and it is only a matter of time before these systems are scaled up. Therefore, it could be worthwhile to implement in Diamondiaal in the future (Pant et al., 2011).

Input Output  Electricity  Electricity  Organic waste  Water

Quantitative estimation For this system, it is very difficult to calculate the quantitative values for Diamondiaal because it is not yet commercially available. At this point only trials are done at several locations, but no information regarding the amount of electricity produced could be found. One value that is known is the maximum value of 3.9 W/m2 that is obtained with the strain of Geobacter sulfurreducens in a two chamber MFC. This value is obtained from a small scale design. When this system would be scaled up, it could maybe be used commercially.

Advantages  Renewable source of energy  This system purifies water and simultaneously generates electricity  When implemented on a larger scale it could be a great source of energy.

Disadvantages  Not yet commercially available.  High costs for electrode and membrane.

Final Assessment

Based on the research results, all technologies are graded. The grade, displayed as a number of ◊, represents how feasible a technology is for the project of Diamondiaal. Five ◊ meaning completely fit for the purpose of Diamondiaal while no ◊ indicates a very low feasibility. The components that are taken into account in the assessment are the following:  Level of expertise needed to implement and operate a technology  Costs versus benefits  Social acceptability  To what extent a technology is complementary to other technologies

Please be aware that this type of assessment is qualitative and the grade reflects the advantages and disadvantages discussed in the literature study.

Table 10. Grading of selected technologies for comparison.

Explanation scenarios

We built four scenarios in which we implemented the sustainable technologies. We took several steps in the process of building scenarios. First, we selected five driving forces for the scenarios that we think are important for the realisation of Diamondiaal. These driving forces are expertise, scale, aesthetics, involvement and costs.

For these driving forces, we first built the so-called micro scenarios. In these micro scenarios, we made a scale with the two extremes on both ends. The outcomes are depicted in figure 1. The first driving force, expertise, could be either external or internal. So either the expertise to build the sustainable technologies comes from outside of the Diamondiaal community and is done by external professional companies, or the expertise to build the sustainable technologies comes from within the Diamondiaal community, by the inhabitants themselves. The second driving force, scale, could be either on collective level, where the technology is shared by the whole community, or on individual level, where the technology is implemented at the household scale. The third driving force, aesthetics, could be either diverse or more standardized. Future inhabitants expressed the wish to live in homes that would reflect their diverse cultures and personal views on beauty. This would most likely lead to many unique buildings. However, if Sustainer Homes would be contracted, standardised modules are used. The fourth driving force, involvement, ranges between high and low. Inhabitants can be involved in the process of selecting technologies, but also through implementation. If involvement is direct for both activities, involvement is considered high. If involvement is indirect for both activities, involvement is considered low. The fifth driving force, costs, are very much dependant on the type of technology and could range from high to low. Costs are also dependent on whether subsidies are available.

We decided that the first two driving forces will be the axis in the graph, which represents the actual scenarios. The expertise is put on the X-axis and the scale is put on the Y-axis, as can be seen below in figure 2. We will now go briefly through the scenarios, starting from the upper left and going clockwise.

Make It Ours In this scenario, the technologies are implemented on community level by professional external parties. Therefore, there is top-down centralization, where the decision-making process and implementation of the technologies are done externally. This means a low involvement of the inhabitants of Diamondiaal combined with high costs.

Do It Together In this scenario, the technologies are also implemented on community level, but this time by the inhabitants themselves. Therefore, there is bottom-up centralization, where the decision-making process is done by a board of representatives of the community, and the implementation of the technologies is done internally. This means medium involvement of the inhabitants combined with medium costs.

Do It Yourself In this scenario, the technologies are implemented on household level, which means individually. Here, the inhabitants may choose themselves which technologies they would like to implement in their own household, and build it themselves. This results in a high diversity in terms of aesthetics of households in the community. The involvement of the inhabitants is high and the costs are low.

Make It Mine In this scenario, the technologies are also implemented on household level, but this time by external parties. Inhabitants may decide which technologies they would like in their household, but they don’t build it themselves. Therefore, involvement and costs are medium.

Now that the general aspects of the scenarios have been explained, we will continue with the scenario building process and fill them with sustainable technologies and include the SWOT analysis.

Make It Ours

Energy Water Food production

Wind power Green roof Green houses

Anaerobic bio-digester Roof catchment Composting

Co-generation Activated carbon

Reverse Osmosis

Underground and Above tank

Advantages:  Off-the-grid and completely self-sufficient due to large scale and high-tech systems.  High reliability on the efficiency of large-scale technologies with consistent quality.  Technologies are shared with all people.

Disadvantages:  Technologies are already there, so low citizen involvement in the decision- making process.  High costs  Dependency, because high-tech systems on large scale require professional help and expertise.  Chain principle: when one technique fails the whole circle of techniques could stop working.

Do It Together

Energy Water Food production

Smaller Windmills in a field Roof catchment Aquaponics

Wood chip burner Bio sand filter Greenhouse

Solar thermal heating UV radiation Composting

Solar panel Underground tank Dry toilets

Advantages:  Technologies are shared with all inhabitants.  Inhabitants will work together to find solutions and to build the community, which creates a high level of solidarity.  Community governance by citizens themselves.

Disadvantages:  Dependency, because knowledge and expertise within the community need to be sufficient to implement the technologies.  Uncertainties on the circularity of the technologies and actual level of self- sufficiency.  Necessity to abide by the rules defined by the community.

Do It Yourself

Energy Water Food production

Solar thermal energy Roof catchment Cold frame

Solar panels Bio sand filter Composting

Wood chip burner UV radiation Window farming

Small windmill Above tank

Advantages:  High individual involvement due to DIY technologies.  Low costs.

Disadvantages:  Not completely self-sufficient and not off the grid, due to small scale and low technologies.  Low production of energy, water and food, due to low-tech systems.

Make It Mine

Energy Water Food production

Solar panel, Roof catchment Vertical farming

Heat pump air to air Activated carbon Composting

Heat exchanger Reverse osmosis Dry toilet

Above tank

Advantages:  All technologies complement each other.  Inhabitants select their housing from an assortment of possible housing options.  There is certainty of tested and proven technologies.

Disadvantages:  All houses are prefabricated.  Houses and technologies are already there: low involvement of the inhabitants in the decision-making process.  Dependency, because professional help is required for the building process and maintenance.

Recommendations

Our team (S-ACT 1689) is the first group of ACT students working on the project called “Diamondiaal – a sustainable community for the future”. Since the project is only 8 weeks long, we had to make choices regarding which topics to take into account. We decided to focus on the feasibility of combining existing sustainable technologies for the construction of Diamondiaal. The following recommendations are important topics that, eventually, have to be taken into account and could be used as a starting point for future (S)-ACT students.

Financial analysis of each sustainable technology Each sustainable technology described in the compendium has a different range of costs. As a next step, diving into the feasibility of expenses for each technique will be helpful for Diamondiaal inhabitants to make choices regarding their available financial budget.

Soil and building restrictions As already explained in the qualitative constraints, within the 1.74 ha available for the Diamondiaal community in Oosterwold Almere, a soil subsidence of 0.8 m is expected in the next 50 years. This is a problem regarding the construction of houses and the implementation of some technologies, such as below ground heat- and cold storage systems. Soil subsidence may cause the risk of possible flooding of the land. In order to make a viable plan, focus has to be put first on the possibility of alternative constructions that are able to maintain the structure and functionality of each system, despite these “limitations”.

Phone application for better communication within Diamondiaal During one of the meetings we had with Inspiratie Inc., there was the wish expressed by the inhabitants of having a phone application to improve communication, and share ideas and expertise. Considering the diversity of people regarding age, culture and backgrounds, this application would help them to communicate between each other in a faster and more efficient way.

Focussing in the details In this project, many technologies have been considered and taken into account. In order to have certainty, regarding feasibility and demand for the community of Diamondiaal, an in-depth focus should be considered for each scenario. Future students could lay their attention on a single technology or on sustainable technologies for each topic described (water, energy and food production).

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