RENEWABLE ENERGY SOURCES IN SERBIA SOLAR AND WIND ENERGY Where is Serbia? • Republic of Serbia is an inland country located at the crossroads of Central and Southeast Europe with the 2 area of 88 361 km . • Total population of about 7 million. • Serbia covers the southern part of Carpathian Basin and the central part of Balkan Peninsula, lying between Balkan and Carpathian mountain ranges in Europe the east, and Dinaric Alps in the west and southwest. Balkan peninsula • Forests and arable land represent about 25% and 36% of total area. • Major rivers are Danube, Sava, Morava, Drina and Tisa. • The capital Belgrade is also the largest city (with metropolitan area population of 1.7 million) located at confluence of Sava and Danube rivers where Pannonian Plain meets Balkans.
Climatic conditions in Serbia
• Serbia is located between 41o46’40’’ and 46o11’25’’ of the north latitude and 18o06’ and 23o01’ of the east longitude. • Serbia belongs to the continental climate regions which can be divided into the continental climate in the Panonic lowlands, moderate-continental climate in lower parts of the mountain region and the mountain climate on high mountains. • Relief substantially influences the climate of Serbia. Parallel to the coast of the Adriatic Sea spreads the range of the Dinars mountains of Montenegro which prevents more intensive invasion of the air masses from the Adriatic Sea towards the areas of Serbia. Climatic conditions in Serbia
• From the other side the territory of Serbia is through the Panonic lowlands widely exposed to the climate influences from the north and east. • Along the valleys of Kolubara, Big and South Morava the air masses float to the north-south and vice versa. • The climate of Serbia is heavily influenced by air masses of certain physical characteristics. The biggest influence is exerted by the air masses formed over Siberia, Artic, Atlantic Ocean, African land and the Mediterranean. Over these areas a field of high air pressure is formed. • On the territory of Serbia often cold air from the Siberia penetrates and rarely from the Artics. Meteorological data of some cities in Serbia in the period from 1961 • Table is formed on the basis of meteorological data of the Republic Hydrometeorological Institute of Serbia http://www.hidmet.gov.rs/index_eng.php • Unfortunately for Čačak there are no continuous data for the given period.
Average daily sunshine duration for the mentioned cities is 5.4 h Natural wealths in Serbia Basic Structure of the Serbian Energy Sector Generation, Distribution, Supply – EPS -
• PE Elektroprivreda Srbije (EPS) is the largest company in the country (it employs around 32.000 employees). • EPS is 100% state owned and holds licences for the following business portfolio: • coal production • electricity generation, • electricity trade, • electricity supply, • distribution of electricity.
EPS - power plants, coalmines and distribution companies Serbia will face serious energy shortage in the near future
• The rapid consumption of coal reserves takes toll on coal power plants—the old warhorses of energy production sector—accounting to approximately one-half of the current total primary energy supply. • Apart from nuclear waste disposal problems and political issues that cannot be overemphasized, limited resources of uranium, both local and global, make nuclear energy an unlikely sustainable substitute for fossil fuels. • Within next two-three decades, Serbia will have to rely much more on renewable energy sources to The largest lignite mining region – the Kolubara satisfy some of the steadily increasing energy Basin- has reserves estimated at 2.2 billion tons. demand. It is one of the biggest deposits in Europe with an annual production of around 22.6 million tons of lignite. Renewable energy status • In order to accomplish the main country’s target “20-20” signed as a candidate for the new member of European Union and increase the RES in energy system by 20%, Serbia must improve the utilization of RES. • Up to now RE generation has been mostly based upon the exploitation of hydro and biomass/waste resources, which includes big hydropower dams and biomass heating systems. • The biomass/waste contributed the total final consumption with 1,152 Mtoe while the HPPs added up 335 Mtoe. • Biomass potential is abundant especially in wood and agriculture such as crop farming, cattle breeding and fruit processing. This potential also includes biodegradable animal waste which is not utilized at all. • Electric power sector beside the hydro and biomass resources had injected 63 Mtoe from geothermal and 81 Mtoe from wind/solar energy. • In wind power the potential goes up to 10,000 MW while in small HPPs are projected to be up to 500 MW.
Renewable energy status - hydro
• Regarding the small HPPs, the reach point of 500 MW is still far away for Government of Serbia, even though all the cadasters of small HPPs had been made 20 years ago. • Currently there are around 180 operational power plants, contributing over 60 MW in the energy system, which is far less than it was expected. • More than 856 sites have been select as the preferred locations for the development of small HPPs with capacities up to 10 MW - only five of them were put in the operation during 2015 and small number are waiting the final commissioning in 2018. • The main obstacle is connected to low technical and economic viability of most of the sites, underpinned with warning brought by the main water company “Srbija vode” that this power plants can damage almost 3,000 km of water flows. Opened in 2015 Opened in 2016 Renewable energy status - wind
• The estimation of wind energy potential depends mostly upon the technical feasibility of electric power system to adjust to stochastic nature of energy generated from this renewable source. • Also it is important to emphasize that average age of power line infrastructure in Serbia is over 25 years and in development stage it has been only planned to operate as radial network (one direction) while the implementation of more RES in the energy system implies that this network should transform into grid with distribution nature. • This implicates the necessity to invest more in the infrastructure and therefore decision- makers have concluded to invest another 90 million into the reconstruction, modernization and rehabilitation of distribution network by 2020. • Taking into account the both, technical and infrastructure issues, the potential of 10,000 MW mostly in eastern Serbia, area of Zlatibor, Kopaonik and Pešter, has been driven down to 500 MW that can be accepted by the energy system. • Thus the investments in wind energy are not getting the rate as it was anticipated, whereas the first Kula wind park was built in 2015 counting only two wind turbines with capacity of 9.9 MW. • The biggest wind park with capacity of 150 MW is constructed in the vicinity of town Vršac.
Serbian energy policy (on the EU road) • Increase the share of RES in final energy consumption from 21.2% in 2009 to 27% in 2020 (5.8%) • Increase the share of biofuel consumption in the transport sector from 0% in 2009 to 10% in 2020. • According to the National Action Plan for renewable energy, plans for the future division of energy include 36% renewable power, 30% heating and cooling, and 10% transport.
Commitments for renewable energy sources: comparison of RES% Serbia with European Union Member States The key barriers for implementation of RES
• Lack of reliable data • Where are and how big are economically viable RES potential • Planning documents that determined the mode how to use of land (Spatial Plan of the Republic of Serbia, Regional Spatial Plans, Spatial Plans of the unit of local administration, General Urban Plan, General Regulation Plan ...) The key barriers for implementation of RES • Economical barriers • Price of electricity from RES are still more expensive than from classical source • Small GDP and GDP per capita • Political challenges (price of electricity is very small- 6,45 c€/kWh) The key barriers for implementation of RES • Administrative procedures • Lack of legal procedures or • Extremely complicated legal procedures (The process of issuing installation and operation license requires the involvement of several different public authority and is therefore extremely complicated and time consuming) The key barriers for implementation of RES
• Legal Framework • National investment uncertainty • Not enough high Credit Rating (2016, Moody's, B1, postive, Fitch, BB-, stable) • Macroeconomic performances, political stability (banking sector stability, SPECULATIVE GRADE, Capacity to meet financial commitments, risk of changes in business environment and economic conditions, significant credit risk) • Lack of confidence of investor in the national legal system The key barriers for implementation of RES The key barriers for implementation of RES The key barriers for implementation of RES • New Decree on incentive measures New Feed in prices for RES electricity Other activities Other activities Other activities
SOLAR AND WIND ENERGY IN SERBIA
• „The Study of Energy Potential of Serbia for Utilizing Solar Radiation and Wind Energy“ was completed in 2004 (Gburčik P. et al.) within the framework of the Serbian National Energy Efficiency Program, supported by the Ministry of Science and Environmental Protection. • Based on the results of this original study, the Ministry has requested a sequel study whose goal is to determine spatial-temporal distribution of the solar and wind energy potential, that is, to create an atlas of the solar and wind energy in Serbia. • Some results from this project, demonstrate that Serbia has considerable renewable energy resources characterized by the seasonal complementarity of solar and wind energy potentials. Solar energy - European Solar Radiation Atlas methodology • The ESRA methodology is used to create maps of global radiation per unit area at the analytical (national) level. The technical details of the analytical process are proscribed by the World Meteorological Organization. • The analysis for Serbia is based on data from 7 meteorological radiometric stations, which provide desired energy values directly, and data from meteorological heliographic stations (total of 40), which provide sunshine duration data. • The original Angstrom-type regression equation is related with the monthly average daily radiation to the clear day radiation at the location and the average fraction of possible sunshine hours. • Page and others have modified the method using the values of extraterrestrial radiation on a horizontal surface rather than that of clear day radiation: ▪ H is the monthly average daily global radiation on a horizontal surface (MJ/m2day) ▪ H S Ho the monthly average daily extraterrestrial radiation on a horizontal surface = a + b (MJ/m2day) ▪ S the monthly average daily hours of bright sunshine H o So ▪ So is the monthly average daily maximum number of hours of possible sunshine (i.e. day length of average day of month) ▪ a and b values are known as Angstrom constants and they are empirical constans Estimation of Solar radiation
• Solar radiation outside the earth's atmosphere is called extraterrestrial radiation. Daily extraterrestrial radiation on a horizontal surface, can be computed for the day of year n:
243600GSC 360n s Ho = 1+ 0.033cos cos cos sins + sin sin 365 180
284 + n 2 = 23.45sin360 Gsc=1367 W/m is solar constant is the declination angle 365 is the latitude of the location s is the sunset hour angle s = −tan tan (the latitudes in Serbia vary between 42o and 46o)
• The maximum possible sunshine duration So = (2/15) s
• H/Ho is the relative global irradiation and S/So is the relative sunshine duration Estimation of Solar radiation for Belgrade
S - Average daily solar duration H - Average daily global radiation
So - Average daily maximum number of hours of possible Hmax - Average daily radiation clear-day sunshine Ho - Average daily extraterrestrial radiation Estimation of Solar radiation for Belgrade • According to the ESRA methodology the linear relationship between relative global irradiation G/G0 and relative sunshine duration S/S0 has proven to be a good approximation to reality if it is applied to many-year means of monthly means of daily totals of G and S, as demonstrated by the correlation coefficient R.
• The regression coefficient values indicate that the linear relationship represents a good approximation for the subject data. The same conclusion is reached for the data sets from other measurement locations. • Data from the seven meteorological radiometric stations and 40 meteorological heliographic stations are then spatially interpolated by using MapInfo Professional v7.0 on the square grid network (10x10 km) to obtain national distribution maps. ESTIMATES OF SOLAR ENERGY RESOURCES BASED ON SOLAR CLIMATOLOGY
• According to the assessment of solar and wind energies resources Serbia belongs to “sunny” countries. • The lowest measured values in Serbia are similar to the highest ones measured in Austria and Germany, which are leading countries in solar energy utilization. • It has been determined that values of solar energy parameters in mountainous region of Western Serbia are low. This is a consequence of the increased daytime cloudiness characteristic of the region over the summertime. • The global solar irradiations on selected inclined planes are larger than on the horizontal plane. For example, energy on the inclined plane 30o S is about 17% larger than on the horizontal plane. • The next examples illustrates annual distribution of solar energy derived from the measured time series for horizontal plane. This spatial distribution of global solar radiation agrees very well with results obtained by a more accurate GIS-integrated (Geographic Information System) analysis for the entire Europe based on data from both meteorological stations and satellites (METEOSAT). Daily global solar radiation in Serbia on the horizontal surface
• Average daily solar irradiation on the ranges from 1.1 kWh/m2 on the north to 1.7 kWh/m2 on the south during January, and from 5.9 kWh/m2 to 6.6 kWh/m2 during July. • On a yearly basis average value of the global solar irradiation for the territory ranges from 1200 kWh/m2 in the Northwest Serbia to 1550 kWh/m2 in Southeast Serbia, while in the middle part it totals to around 1400 kWh/m2. • Due to this fact Serbia exhibits favourable conditions for the use of solar energy and its conversion into the thermal and electrical energy. Annual distribution of the mean daily global solar irradiation per unit area on the horizontal surface
• The integration of the average daily solar energy for the period of 1 year results in the mean annual income energy of global solar irradiation on horizontal surface of 1.4 MWh/m2 and annual total of solar energy for the whole territory is 1.2 x 105 TWh.
• Number of “sunny hours” is about 2000: yearly sunshine duration ranges from 1604.9 h (Uzice) to 2084.1 h (Pirot);
• In Serbia, solar energy increases steadily from the north-west to the southeast. Daily average of the global solar energy on the plane inclined 30oS in July
• Maps for both plane inclinations are presented to emphasize differences in solar energy values, which are known to be higher as the angle of inclination approaches the site latitude angle (the latitudes in Serbia vary between 42o and 46o). • Consequently, the area of maximum global solar irradiation density for the plane inclined 30oS, compared to the one corresponding to the horizontal plane, is characterized not only by more than 50% higher intensity (>6.6 vs. >4.2 kWh/m2) but also by more than twice the size of covered territory. • The spatial distribution of solar irradiation density also changes favorably with the angle of inclination increase by extending the prime regions from the southeastern corner to include the whole eastern region of the country. Some examples of yearly courses of solar energy in Belgrade under various conditions Monthly variation in mean values of the daily Monthly variation in mean values of the daily global solar energy transmitted through the ) global (Gm and diffuse irradiation (Dm) on the vertical clear single and double glazing vertical plane (E-W orientation) (E-W orientation)
The corresponding measurement data were recorded in the meteorological station at “Zeleno Brdo” located in the wider downtown Belgrade area. PVGIS and solar maps for the territory of Serbia • PVGIS (Photovoltaic Geographical Information System) is a part of the SOLAREC project (FP7) aimed at contributing to the implementation of renewable energy in the EU. • PVGIS methodology comprises solar radiation data, PV module surface inclination and orientation and shadowing effect of the local terrain features. • Yearly average of the optimal panel inclination ranges from 32o (Negotin, Zajecar, Pirot) to 35o (Novi Pazar, Vrsac, Beograd); • It is clear that average solar irradiation is not dependent on geographical latitude only. • There are regional differences in global solar irradiation due to terrain features and climatic Yearly sum of total solar irradiation incident on optimally conditions. inclined south-oriented PV modules in kWh/m2 Comparison of available annual quantities of the energy of the global sun radiation on the horizontal surface, on the territory of Germany and Serbia
• Average values of the energy of global radiation on the territory of Germany is around 1000 kWh/m2 whereas for Serbia that value is around 1400 kWh/m2. • In Serbia sun energy evenly increases from northwest to southeast, while in Germany the situation is more complex. • The least values are not on the north but in the central part of the country due to increased turbidity of the atmosphere (linke turbidity). Geographycal position and the results of PVGIS calculation of the yearly average values
Estimated losses in PV solar plants of 1 MW Comparison of total for year electricity production of different types of PV solar plants with monocrystal silicon solar modules of 1 MW Solar power plants in Serbia
• The Serbian Government has introduced several measures and incentives as FIT system in order to boost the faster deployment and increase the shares of solar energy in final energy consumption. • Currently, the utilization of the solar energy is almost negligible, although the goal of 10 MW for privileged power producers (PPP) and fund prepared for the Government support for PV plant SOLARIS ENERGY www.solarisenergy.co.rs development was reached during 2017. • Among the other project, the largest PV power plant has 2 MW output and it was completed in November 2014 by local company Solaris Energy (Kladovo). • The cost of project reached 3 million euros and loans were provided by German KfW Bank and Procredit Bank. Solar power plants in Serbia
• The biggest investment in solar energy production was planned for the southern region of Serbia, between Niš and Vranje where the potential of the sun is reaching the peak point. • It was planned to build a solar park with capacity of 1000 MW and investment of over 1.7 billion euros by the Securum Equity Partners Europe (SEPE) originally from Luxembourg. • Also this incorporated the establishment of three solar panel factories that should have been the main exporters of the panels required for the project itself. • This huge project, one of the largest ones in this part of the Europe, has never reached the starting phase of construction even though everything was planned for mid of 2013. The main obstacle regarding this project is linked to agreement signed between Government on one side and SEPE on the other. This agreement stipulated that Serbia was obligated to prepare the land for the project and transfer it free of charge to investor and form the time this was agreed in 2011, it did not happen while SEPE begun the arbitration process against Serbia. Solar power plants in Serbia • This case showed the decision-makers to approach each subsequent project more carefully and thus it was with several solar parks constructed in period after the SEPE agreement, among which the construction of solar park in Beočin with capacity of 1 MW in 2014. • This project conducted by Serbian subsidiary of Slovakian Prima Energy with investment over 1.8 million euros. • Also the solar power plant in Merdare (Kuršumlija), along with PV plant in Beočin and PV plant Solaris, represent the biggest PV constructions in Serbia with investment over Beočin PV plant ( 1 MW) 3.5 million euros. • Up to now 91 solar power plant installations have been conducted in Serbia, reaching the output power of around 8.5 MW in total. • When compare these numbers and the technical viable capacity of electric grid to adopt up to 450 MW of solar power plant power, it is obvious that the development of PV plants in Serbia is still in the beginning phase. Merdare PV plant ( 2 MW) Wind energy - European Wind Atlas methodology • The present analysis of the wind climatology on the national level is performed by applying the EWA analytical model on daily time series obtained by the standard meteorological observations at synoptic and climatological stations. • The time series of data span three decades and refer to observations within the network of 48 meteorological stations. • These long-term observations imply measurements of wind speed at the standard height of observation of 10 m over the ground level. • In order to obtain maps of wind energy density at a common reference height of 100 m over the ground level, it is necessary to determine the wind speed and the corresponding Weibull distribution parameters at that height. This is achieved by extrapolation of the standard meteorological data that is performed by using the power law for the wind speed variation with height: 푧 푢 = 푢0( ) 푧0 푢0 - the mean wind speed at the observation height of 푧0 = 10 m over the ground level 푢 - the mean wind speed at the selected height z (in this case z=100 m) - the wind shear coefficient (also known as the Hellman exponent) - depends upon the topographical characteristics of the terrain, and the stability of the air Wind energy - European Wind Atlas methodology • The wind shear coefficient is in Serbia encountered in five classes within a relatively narrow range 0.18–0.28 that is almost completely covered by the four micrositing examples:
• Wind energy flux is the power density of wind flowing with a speed u through a perpendicular surface ( is the mass density of air): 1 푃(푢) = 푢3 (W/m2) 2 • If the common definition of the time average value of the wind speed 푢 = 푢(푡) taken over 1 푇 :the period T is used as 푢 푇 = 푢 푡 푑푡 the wind energy density can be defined as 푇 0 1 퐸 = (푢3) (Wh/m2) 2 푇 • The processed data from the 48 meteorological stations are then spatially interpolated within the computation domain (i.e., territory of Serbia) by using MapInfo Professional v7.0 on the square grid network (10x10 km) to obtain spatial distribution maps. ESTIMATES OF WIND ENERGY RESOURCES BASED ON WIND CLIMATOLOGY
• According to the Implementation Program for the Strategy of Energy Development total exploitable potential of wind energy is assessed up to 0.2 Mtoe/year. • Implementation of this program predicted an additional production of renewable electricity by wind power stations of 45.4GWh (0.0039 Mtoe) in the period from 2007. • According to the assessments of wind energy potentials in Serbia performed over the last two decade, the total exploitable potential of wind energy is twice higher than the official estimate (up to 0.38 Mtoe/year). • The wind energy potentials in certain parts of Serbia are beyond doubt suitable for utilization. Annual mean wind energy density distribution (hight 100 m)
• The total amount of wind energy available annually for the whole territory of Serbia is about 2.4103 TWh. • The annual average wind energy per unit area at height of 100 m is in the range of 900 kWh/m2 (in southern and southwestern Serbia) to more than 2700 kWh/m2 (eastern Serbia). • The primary regions are southern Banat, the Danube river valley—enveloped by the Kosava wind region and mountain ranges of the eastern and southeastern Serbia. ✓ Maximal values of wind energy have occurred in the Kosava wind region with the annual wind energy density surpassing 2700 kWh/m2. ✓ The Danube river valley region and the lowermost part of the Morava river valley is in the range of 2100–2700 kWh/m2 ✓ There are also some mountainous regions, primarily in eastern and southeastern parts of the country, with considerable wind energy potential
Wind energy meteorological parameters are inherently characterized by an expressive annual variability • In Serbia, the maximum availability of wind energy typically occurs during winter when the energy consumer requirements are at the highest level. • The availability of wind energy is reduced significantly with the onset of vegetation period (April–October). • The maximum availability of wind energy coincides with the highest consumption requirements in the heating season and some mountain areas.
Annual course of the mean wind energy density by directions in Vrsac (45o7’N 21o18’E) a site typical of the southern Banat Wind profiles at two meteorological stations located in the central Serbia • The relatively significant gradients of wind speed increase with height are related to landscape characteristics of the two meteorological station sites: the forested suburban flat terrain and the hilly forested town outskirt, typical of Krusevac (a) and Tekija (b- the lower end of the Danube river gorge). • Wind speed profiles are obtained by the power-law extrapolation with identical wind shear coefficient =0.22. • Corresponding power density profiles follow straight forwardly. Windpark „Kovačica“ -Vojvodina province- • Comprises 38 wind turbines providing a total potential power capacity of 105 MW. • The wind turbines are three-bladed downwind, horizontal axis. • Wind turbine hub height is 110 m while the tip height with a vertical propeller is 170 m. • Diameter of rotating blades is 120 m. • The turbines are connected via 33kV underground cables and junction stations which are connected to a Substation within the wind farm. • The total area occupied by the wind farm is 3,711 ha. Kosava windpark Vrsac -Vojvodina province- • The construction of the wind farm, which began in June 2017, is worth a total of EUR 117 million. • Košava Phase 1 includes 20 wind turbines totaling 69 MW of power capacity. The wind farm will start operating by the end of 2019. • The Phase 2 includes 19 wind turbines with a total power of 78.2 MW - the construction should begin in early 2019. • MK Fintel Wind is owned by Italy’s Fintel Energia Group and Serbia’s MK holding. • At the end of 2015 MK Fintel Wind opened a 9.9 MW Kula wind farm, the first in Serbia, and in October 2016 in Zagajica near Vršac 6.6 MW La Piccolina wind park. COMPLEMENTARY REGIMES OF SOLAR AND WIND ENERGY
In Serbia, the maximum availability of wind energy typically occurs at the peak of energy demand, during winter. The solar energy availability culminates during summer. The complementarity of solar and wind energy is especially pronounced in the Kosava wind region. The daily amounts of solar energy in July range from below 6.0 kWh/m2 in the west to over 6.5 kWh/m2 in the southeast of the country.
Average wind energy density at the height of 100 m Daily average of global solar energy over the ground level during the heating season on the horizontal plane in July Annual courses of solar and wind energy in Belgrade
• The solar energy ratio between December and July is approximately 1:6 • The wind energy ratio between July and March (or November) is 1:3 • The ratio between aggregated solar and wind energy over the period August–September and that over the period March–April is slightly below 1:2
• Relative fluctuation of solar energy influx over the year can be compensated by adding wind energy, thus decreasing the ratio from 1:6 to less than 1:2. • The effects of complementarity are even more dramatic if nocturnal periods (absence of solar radiation) or the periods of “adverse” weather conditions (typically, reduced solar radiation and strong winds) are taken into account. • The similar complementarity trends were observed in other locations across Serbia. CONCLUSIONS • Research highlights presented herein demonstrate that Serbia has considerable renewable energy resources characterized by seasonal complementarity of solar and wind energy forms. • The meteorological data indicate that the mean annual energy influx of global solar irradiation on horizontal plane is 1.4 MWh/m2. • The global solar irradiation on the optimally inclined plane would be significantly higher. • The annual wind energy density in the southern Banat core of the Kosava region exceeds 2.7 MWh/m2. • The wind potential during the season of peak electricity demand surpasses 1.8 MWh/m2, indicating that exploitation of this potential for electricity generation could improve the negative electrical energy balance in that season. • There are also some barely explored mountainous regions, identified at present primarily in eastern and southeastern Serbia with considerable wind energy potential.