M JORDANOVIC ET AL.: POTENTIAL OF THE SOUTH SERBIA IN RENEWABLE ENERGY SOURCES AND THEIR EXPLOITATION POTENTIAL OF THE SOUTH SERBIA IN RENEWABLE ENERGY SOURCES AND THEIR EXPLOITATION MĂƌŝŶĂ:ŽƌĚĂŶŽǀŝđ University of Nis, Faculty of Civil Engineering and Architecture, Serbia PhD student, marina.jordanovic@gmail.com LũŝůũĂŶĂ:ĞǀƌĞŵŽǀŝđ University of Nis, Faculty of Civil Engineering and Architecture, Serbia PhD student, jevremoviljiljana@gmail.com MŝůĂŶŬĂsĂƐŝđ University of Nis, Faculty of Civil Engineering and Architecture, Serbia PhD student, milanka3970@gmail.com Branko A.J Turnšek University of Nis, Faculty of Civil Engineering and Architecture, Serbia PhD., Associate Professor, ajbranko@yahoo.com AŶĂ^ƚĂŶŽũĞǀŝđ University of Nis, Faculty of Civil Engineering and Architecture, Serbia PhD student, stanojevicana1991@gmail.com IƐŝĚŽƌĂŽƌĜĞǀŝđ University of Nis, Faculty of Civil Engineering and Architecture, Serbia PhD student, isidordjordjevic7@gmail.com ABSTRACT Renewable energy sources (RES), in the developed countries of Europe and the world, are slowly but surely taking the primacy in use compared to conventional sources Limited capacities of fossil fuels, coal, oil, natural gas and their very detrimental effect on the environment have been made to think about energy sources in a different - more alternative way In order to meet all the human energy needs that are growing each day, more and more money is being invested in the construction of plants for the production of energy from renewable sources The benefit is substantial: the consumption of fossil fuels decreases, the environment is protected, and the emission of harmful gases is reduced Thus, the EU began to implement a global action to mitigate the dangers of using fossil fuels and committed itself to reducing the total CO2 emissions to the environment by all means available As urban areas are far more demanding consumers than rural areas, many cities in Europe have adopted measures regarding the use of RES that has been in place for years Thus, the city of Niš in 2014 also adopted the Sustainable Energy Action Plan (SEAP) of the City of Niš The aim of this paper is to present the potentials of southern Serbia in renewable energy sources and their exploitation with the specific focus to demonstrate how the energy produced in this way may contribute in more environmentally friendly development of the city Keywords: renewable energy sources, South Serbia, potential, clean energy, ecological awareness ICUP 2018 ~ PROCEEDINGS ~ Nis: November 2018 97 M JORDANOVIC ET AL.: POTENTIAL OF THE SOUTH SERBIA IN RENEWABLE ENERGY SOURCES AND THEIR EXPLOITATION INTRODUCTION The majority of countries around the world will face serious energy shortages in the near future The high demand for electricity and heat, as well as the increase in the number of inhabitants in the world, lead to a critical available quantities of fossil fuels Consequently, many countries will force their economies to be orientated towards strategies of the use of renewable energy sources Combustion of fossil fuels, especially those based on oil and coal, is the main cause of global warming and the increase in CO2 emissions in the atmosphere All these changes that directly affect the Earth's ecological system can affect the reduction of dependence on coal use and encourage the development and use of renewable energy technologies Due to the large global problem (a deterioration of the Earth's eco-system and the less controlled consumption of fossil fuels), the promise and assumed responsibility of the EU to increase the share of renewable energy sources in electricity production by 20% by 2020 relative to 2010 (EU "ENERGY 2020") Many documents have been created and adopted on this topic that invite and bind the responsibility of all EU member states The planet Earth is the only one and we have to unite the forces to preserve it, for the benefit of all its inhabitants and future generations As Serbia is part of the world, it have to, in accordance with its capabilities, economically, primarily contribute to environmental protection and reduced consumption of fossil fuels and to the increased use of renewable energy sources RENEWABLE ENERGY SOURCES IN THE TERRITORY OF SOUTHERN SERBIA By definition, renewable energy is energy that is exploited at the same speed as it is naturally renewed Renewable energy sources are all non-fossil origin, which are: x x x x x x Sun energy Wind Energy Biomass Geothermal energy Hydropower Waves and tides The Republic of Serbia has no access to the sea so that waves and tides, as renewable energy sources, cannot be its natural potential in generating energy from these sources 2.1 The Energy of the Sun The sun is a great source of energy According to an estimate, the capacity of solar energy is about 14,000 times greater than the total energy consumed by humanity today The use of this energy as a source of energy requires the fulfilment of many preconditions for it The economic and technological development of the state is crucial in the choice of using this energy source as well as the geographical position of the state In Serbia, the number of sunny days, according to the data provided by the Ministry of Energy, is higher than 2000 hours annually However, although this is much more than in many European countries, this potential is still not fully exploited in Serbia The reason for this is the high price of the receiver of solar radiation and accompanying equipment (Jankovic V 2004) In Serbia, this system, so far, is used exclusively for the production of heat energy, so its application is on individual residential buildings and tourist facilities just for heating the water In the territory of southern Serbia, Niš, Kuršumlija and Vranje have the greatest potential of this renewable energy source (Figure1) 98 ICUP 2018 ~ PROCEEDINGS ~ Nis: November 2018 M JORDANOVIC ET AL.: POTENTIAL OF THE SOUTH SERBIA IN RENEWABLE ENERGY SOURCES AND THEIR EXPLOITATION (a) (b) Figure 1: Average Daily Energy of global solar radiation on a horizontal surface [kWh / m2] in the territory of Serbia (a) in January (b) in July Source: energetskiportal.rs 2.2 Wind Energy People has served the wind power since ancient times, initially for the launch of sailboards, in the mills for the grinding of grain The windmills also played the role as a water pump and for many other purposes Today, the wind as a renewable energy source is used for the production of electricity (Wagner, Mathur, 2013.) The use of wind energy in Serbia is at a very low level Extremely windy areas in Serbia are in Vojvodina, above all, mountain areas of southern and eastern Serbia (from 100 to 1500 m above sea level) However, as wind generators start to operate at a wind speed between 3.0-5.0 (m/s) and the highest average wind speed in southern Serbia is 1.4-3.10 (m / s), (Figure 2) it is concluded that this part of Serbia has no potential in this renewable energy source Any investment in wind generators for the production of electricity in this area would not be profitable (a) (b) Figure 2: Average annual values a) wind power, b) wind energy in Serbia at a height of 100 m above sea level [kWh/m2] Source: energetskiportal.rs ICUP 2018 ~ PROCEEDINGS ~ Nis: November 2018 99 M JORDANOVIC ET AL.: POTENTIAL OF THE SOUTH SERBIA IN RENEWABLE ENERGY SOURCES AND THEIR EXPLOITATION 2.3 The Energy of the Biomass The potential of the biomass energy is very large and accounts for about 80% of the total potential of renewable energy sources Biomass is defines as a biodegradable part of the remains of biological origin (plants and animals) as well as the biodegradable part of industrial and municipal waste (Jordanovŝđ͕:ĞǀƌĞŵŽǀŝđ͕sĂƐŝđ͕ 2012) Biomass is a carbon-neutral renewable energy source that is constantly available in eco-systems It come out from wood (timber remains) or agricultural The timber biomass is created during the felling of forests or industrial processing, while agricultural crops leave the crop residues or liquid manure from animal farms (Henning, Mardsjo, 2010) Combustion of biomass yields heat energy that was used up until recently for heating and heating water, but today it is used for electricity generation For energy purposes, biofuel is also used, which is caused by the transformation of biomass into the liquid state, as well as biogas which is degraded biological waste in the gaseous state Serbia is extremely rich in arable land and forests, so its potential in biomass is significant The available quantity of wood, which is mostly represented in central and southern Serbia, amounts to 1.53 million tons of oil equivalent Agricultural biomass is available mostly in Vojvodina and its potential is estimated at around 1.67 million tons of oil equivalent, but the utilization rate is not more than 2% Despite the rich biomass resources, taking into account its biodiversity and its distribution, it is not sufficiently used in Serbia for efficient energy generation In the south and east of our country, the wood mass is primarily and uncontrolledly used as a wood for heating Such use of wood could be much better utilized In the specialised facilities, this biomass could be used simultaneously for the generation of heat and electricity One of the most advanced plants for obtaining combined energy is CHP (Combined Heat And Power) While in other similar plants, the primary fuel utilization factor is from 30 to 40%, in CHP plants it reaches more than 85% Waste thermal energy, in the form of steam or hot water, released during the electricity generation process is used for the needs of the technological process or for heating the space This saves significant savings in the total cost of the plant The CHP plant has a wide range of applications (wood industry, dryers, breweries, dairies, food industry, etc.) As far as southern Serbia is concerned, on the basis of the data on the domesticated livestock and the raw materials on herbal base as resource for the production of biogas, it can be concluded that this part of Serbia does not contribute much in the total utilization of this renewable energy source (SEAP 2014) However, as the Government of the Republic of Serbia has defined as one of its strategic goals to increase the production of electricity from renewable sources, the current situation may change in the shortest possible time 2.4 Geothermal Sources In the Republic of Serbia, according to the Ministry of Energy, there are several hundred wells with geothermal water The total potential of these sources is estimated up to times higher than achieved Otherwise, the potential of this resource is 185,000 t equivalent oil Judging by potential, Serbia belongs to the richer countries of the region The reason for the poor exploitation of geothermal resources in Serbia is unsystematic approach in exploration and preparatory works, as well as inadequate incentives for the use of this energy source Territories in Serbia are built of hard rocks, and due to such favourable hydrogeological and geothermal characteristics in Serbia there are about 160 geothermal water sources with a temperature of more than 15qC The warmest sources are in Vranjska Banja with a water temperature of up to 96qC, which makes it the hottest spa in whole Europe The total yield of all natural geothermal sources is about 4000 l/s And the total amount of heat accumulated in geothermal water reservoirs in Serbia, at a depth of km, is about times higher than the equivalent thermal energy that would be obtained by combustion of all types of coal from all the sites in Serbia Unlike other renewable energy sources, geothermal energy does not depend on the season, the weather conditions and the time of the day The biggest "drawback" of this energy source is the high cost of investment Return of invested funds in the construction of a power plant for the production of electricity from geothermal sources are guaranteed, but with the delays from even up to 20 years The geothermal sources on the territory of southern Serbia are present Only in the vicinity of Nis there are several: in Niska Banja, Banja Topila, Ostrovica and Miljakovac Still, all these sources are with relatively low water temperature (up to 60qC, in Niska Banja 35,5qC), which is still uneconomic for developing the large facilities for the production of heat and electricity So far, these geothermal sources are used for heating smaller objects for different purposes and for the purpose of treatments In Niska Banja, thermal pump with the power of 5MW are using thermal waste water with temperature of 25qC for heating the hotel and the rehabilitation centre 100 ICUP 2018 ~ PROCEEDINGS ~ Nis: November 2018 M JORDANOVIC ET AL.: POTENTIAL OF THE SOUTH SERBIA IN RENEWABLE ENERGY SOURCES AND THEIR EXPLOITATION 2.5 Hydro-energy The Republic of Serbia is extremely rich in water Hydropower is the most important renewable energy resource in Serbia (SEAP 2014) About 10.4% of the total energy potential is found in watercourses where small hydropower plants can be built Hydroelectric energy is obtained through two phases In the first phase, the potential energy of the water mass drives the hydraulic turbine and turns into mechanical energy, and in the second phase this mechanical energy is driven by a generator that turns into electricity The power generated by the electricity depends on the flow of water mass and the difference in the level between the source of the watercourse and the outflow of the accumulation – drop (Kaschny, O) Majority of hydropower plants require the construction of a dam that allows regulation of the watercourse but also an increase in the fall Environmental impacts of small hydropower plants are negligible in relation to the impacts of large hydro power plants For this reason, small hydropower plants are increasingly being built around the world The relief of southern Serbia is suitable for the construction of such plants, and it is not surprising that more and more foreign investors invest in the construction of small hydro power plants in this part of Serbia Investments in these capacities also depend on state incentives for building energy capacities from renewable energy sources in accordance with legal regulations that should attract the capital of private investors Thanks to the company “Inter-energo” from Ljubljana in the Municipality of Vlasotince, the "Poštica" hydroelectric power plant (Figure 3) was put into operation, thus starting the investment cycle of electricity production from renewable energy sources in Serbia The users of such small plants not only produce electricity for their own needs, but the surplus of energy is sold to the electricity distribution, which indicates that the investments in such plants are very much paid off The construction of small hydropower plants is of great strategic importance for the country The local population would be supplied with electricity produced by non-polluting sources of energy that would not pollute the environment, imports of energy and electricity would be reduced, and the growth of employment of domestic capacities for production of equipment and the execution of works would be accelerated It should be noted that, regardless of size, the hydroelectric power plant replaces coal consumption by about 1.4kg per kWh of electricity produced Figure 3: Small hydropower plant in the municipality of Vlasotince “Poštica” Source: http: //www.pcpress.info 2.6 Summary of the renewable energy resources in Southern Serbia The geographical disposition and climate characteristics of the Republic of Serbia are as rarely as any country in Europe Rich natural resources (rivers, forests, geothermal springs, arable land, etc.) in Serbia are not ICUP 2018 ~ PROCEEDINGS ~ Nis: November 2018 101 M JORDANOVIC ET AL.: POTENTIAL OF THE SOUTH SERBIA IN RENEWABLE ENERGY SOURCES AND THEIR EXPLOITATION sufficiently used in the process of generating electricity and thermal energy (for heating) from these renewable energy sources Economic development of Serbia and its readiness to invest in energy producers from alternative sources is still not on the EU countries level The region of Southern Serbia has potential in renewable sources of energy First of all, there are hydropower (Figure 4) and geothermal energy Biomass energy does exists as a great potential but its utilization is only 2% Wind energy potential, in this part of Serbia, is limited due to climate characteristics and because of it is not used On the other hand, the sun's energy is a great potential but at this moment is underused and exploited only for individual needs Figure HidroelektrĂŶĂΗ^ŝđĞǀŽ" Source: http: //www.pcpress.info CONCLUSION The common characteristic of all renewable and alternative technologies for the production of heat and electricity is relatively high level of initial investment, but also their later low operating price The extent to what extent a country will use renewable resources depends exclusively on its economic power One thing is certain, the use of alternative energy sources will be inevitable The increase in the number of inhabitants on the planet Earth and the increasing needs for the energy of modern society influence slowly to change the ecological awareness of all on this issue Responsible behaviour in all spheres of society is necessary in order to preserve the environment Before investing in such technologies it is necessary to carry out a detailed analysis of price and potential Not all sources have the same potential in a certain part of the world as in Serbia Renewable energy sources are the main backbone of Serbia's energy independence in the future The total potential of energy from renewable sources can satisfy 1/4 of the annual needs of Serbia for electricity According to the Ministry of Energy, in 2004, Serbia spent energy equivalent to burning 40 million tons of oil From renewed energy sources, 0.96 million equivalent t were obtained during the same year, and the potential of the utilization is several times higher (around million t) Solar energy in Serbia is still unprofitable for the production of electricity on a larger scale, but it is used for the purpose of heating individual objects for different purposes Geothermal sources are insufficiently warm (used for the heating of facilities and for the purpose of treatment), wind energy is not sufficiently tested (no wind generator in Serbia still gives electricity), while biomass is more and more present The most successful projects are in the construction of small hydropower plants The use of renewable energy sources promotes the economic growth of one country and 102 ICUP 2018 ~ PROCEEDINGS ~ Nis: November 2018 M JORDANOVIC ET AL.: POTENTIAL OF THE SOUTH SERBIA IN RENEWABLE ENERGY SOURCES AND THEIR EXPLOITATION the extent to which the utilization of natural resources will depend on the implementation of the National Renewable Energy Program The Government Regulation also provides for the status of a privileged producer of electricity from renewable sources REFERENCES Marina Jordanoviđ-Vasiđ;ϮϬϬϵͿUpotreba biomase iz poljoprivrednog otpada kao obnovljivog izvora energije, Nauka+Praksa (ISSN 1451-8341), Vol 12.1, str 60-63, GraĜevinsko-arhitektonski fakultet, Niš DĂƌŝŶĂ:ŽƌĚĂŶŽǀŝđ͕>ũŝůũĂŶĂ:ĞǀƌĞŵŽǀŝđ͕DŝůĂŶŬĂsĂƐŝđ͗^ƵƐƚĂŝŶĂůďůĞĞƐŝŐŶ͗WƌŽĐĞƐƐŝŶŐŽĨ^ŽůŝĚtĂƐƚĞ as a Source of Energy, IV International Symposium for Students of Doctoral Studies 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power plant automation, Schneider Electric Brazil, CDI Power (http://www2.schneider-electric.com/documents/solutions/solution/280small_hydro_power_plant_v1.pdf ) ICUP 2018 ~ PROCEEDINGS ~ Nis: November 2018 103