IcETRAN 2022
KEY NOTE LECTURE:
ELECTRIC ENERGY AND ENVIRONMENT
Slobodan N. Vukosavić, University of Belgrade and Serbian Academy of Sciences and Arts, Belgrade, Serbia
Summary:
Electricity production in Serbia relies primarily on the use of lignite in thermal power plants. In recent years, inadequate development of Serbian energy sector and improper management of coal mines and thermal power plants have led to a significant reduction in electricity production in Serbian coal-fired power plants, production which until recently accounted for 70%. As a consequence, significant funds were spent on imports of electrical energy, thus crippling the investments in energy transition. Over the next decades, one should expect a further decline in production in coal-fired power plants. The available lignite reserves enable the operation of thermal power plants for the next thirty years. At the same time, efforts to reduce CO2 emissions in industry, transport, residential and commercial sectors all lead to increased electricity consumption. The growing imbalance between production and consumption requires timely consideration of appropriate alternative sources. The available energy transition options should be compared in terms of power security, energy availability, efficiency, economic viability and environmental sustainability.
Replacing coal-fired thermal power plants with cheap and efficient natural gas power plants provides the possibility of using a combined gas-steam cycle, which, together with cogeneration, allows up to 80% of energy from the fuel to be used. Combustion of natural gas produces CO2 emissions that are considerably lower than emissions from combustion of coal. However, geopolitical reasons lead to an increase in gas prices and reduced security of supply.
In the years before the European energy collapse 2021-2022, the enthusiasm of public authorities and the civil sector in relying on wind and solar power exceeded the actual capabilities of such plants, while the appropriate technical assessments and measures proved inadequate. Nevertheless, with a conscientious consideration of all the consequences of connecting wind and solar power plants to the grid, with anticipation of all preparatory actions and measures necessary for their integration into the system and with proper consideration of the necessary system changes, Serbia should use wind and solar energy to the full extent as defined by technical and financial boundaries.
Regarding the achievable production of electricity from wind farms, one should keep in mind that Serbia has relatively modest potentials. In windy EU countries, the average value of wind power density at sea is about 6 times higher than in Serbia, while for onshore wind farms, the power density is about 3 times higher than in Serbia. Most of the locations where construction is profitable are found along the eastern borders of Serbia. The most favorable locations have already been used, while most of the remaining locations are in less profitable and/or less accessible terrains. Unlike wind energy, the potential of solar power plants is significantly higher, but very little is currently used. Solar power plants provide their their energy during a shorter part of the day, namely, generation ceases from late afternoon, during the night, only to become available late in the morning. The output of solar power plants decreases during the evening increase in consumption, which greatly complicates their integration into the system, requires considerable storage and increases costs.
Increasing the share of variable sources increases the required storage that would supply the consumers at intervals with no adequate production. Storage capacity grows rapidly with the share of variable sources. The cost of such storage may have a significant impact on the total cost of energy transition. With a larger share of variable sources, the costs of their integration into the system exceeds by large the cost of their construction. If the share of variable sources connected to the network is significant, the costs of storage and grid-stabilization measures are so high that they make further reliance on variable sources financially unsustainable, while the larger volume of unavoidable battery storage poses a very significant risk to the environment. For these reasons, one of the key issues of energy development is planning the optimal share of variable sources in total electricity consumption. The intemperance and neglect of the problem of integration of variable sources leads to the accumulation of problems that can significantly jeopardize the security and availability of supply, eventually leading to an increased dependence on energy imports.
Coal-fired power plants can be replaced by nuclear power plants, which provide decades of electricity supply at affordable prices, and with corresponding CO2 emissions lower than consolidated emissions from renewable sources of electrical energy. While the option of nuclear power plants goes against interests of large industrial groups in EU, France, Slovakia, Hungary and other countries rely heavily on electricity from nuclear power plants, while many EU members plan to expand the nuclear capacity. This creates the need and opportunity for Serbia to closely and proactively monitor the status of nuclear power sector in EU. At the 4th generation nuclear power plants, the problems of fuel procurement and waste disposal are significantly relieved, while safety is significantly increased. Rapid development of technologies creates the need to update planned developments in energy sector in accordance with new knowledge, solutions and experiences.
About 60% of energy from renewable sources in EU is still obtained through the use of biomass. Large amounts correspond to burning wood in small furnace. Wood biomass, agricultural residues and other agricultural and forest waste can be collected and treated in an organized manner by pelletization, torefaction, pyrolysis and other processes to obtain solid or gaseous fuel (biogas / biogas). Putting aside raw wood combustion in small furnaces, previous efforts and projects for the use of biomass in Serbia have not yielded the expected results. In many cases, the outcomes were lower than expected due to logistical problems in collection and storage. Prevailing use of biomass combustion in small furnaces yielded considerable emissions of suspended particles and incomplete combustion products, which further threatens air quality in Serbia.
The use of biomass in energy sector is accepted by the EU and supported by the World Bioenergy Association. Yet, it is contrary to the recommendations of SAPEA, the formal advisor to the European Commission, as well as the recommendations of EASAC. More detailed studies indicate that the assumption of carbon neutrality of biomass ignores the transient, but decades-long increase in CO2 concentration created by biomass combustion, which further complicates the current phase of global warming. Biomass heating in the winter period, in intervals of temperature inversion, creates very high concentrations of suspended particles, which greatly endangers human health in populated areas. Considering collection of biomass, it is necessary to ensure that producers procure raw materials without endangering the forest fund, with exploitation limited to a carefully prescribed part of the annual growth. In the same way, the collection of agricultural waste as well as the cultivation of crops for energy needs should be organized in a way that does not endanger the composition of the land. Biomass can be used as a resource for the production of biogas, methane or methanol that would be used for energy purposes. Treatment can be based on anaerobic digestion or thermochemical conversion of biomass. The constant and relatively rapid development of technologies for biomass processing creates the need to update analyzes and projections related to the use of biomass and biogas production in accordance with new experiences and knowledge.
Electricity production is constantly growing. According to forecasts, annual production will double by 2050. Along with the increase in production, the inevitable negative effects of energy on the environment will also increase. Traditional electricity is largely based on fossil fuels. The impact of fossil fuel combustion on the environment has been well studied. Lignite has a high content of ash, sulfur and numerous toxic elements, including Be, Co, Cr, Mo, Mn, Ni, Pb, Se, Sb and V. In addition to the listed elements, lignite also contains the radioactive elements U, Th, Ra and Rn. Combustion of lignite leads to the release of nitrogen and sulfur oxides, carbon dioxide, arsenic, mercury and other harmful substances. Harmful substances from coal mines, coal processing plants and lignite-fired thermal power plants cause a whole range of diseases, among which diseases of the respiratory system predominate. Civil society organizations, which are advocating for the cessation of lignite exploitation as soon as possible, state that the total health costs caused by burning coal in the EU range from € 15.5 to 42.8 billion a year. This is an indicative estimate that does not include indirect costs due to reduced working capacity, declining quality of life and respiratory diseases in children and youth.
The impact of new electricity sources on the environment has not been sufficiently studied. Pollution during the production and decommissioning of renewable sources, as well as pollution related to the production, installation, operation, maintenance and decommissioning of necessary electricity storage facilities are often neglected, although the integration of renewable energy sources into the system is unthinkable without storage facilities. According to estimates, significant quantities of various minerals will be needed for the needs of the production of electric vehicles and for the needs of the construction of electricity storage in the electric power industry. It is predicted that, if the current trends continue, over the next thirty years, ore will be mined from mines whose volume will exceed the volume of mined ore from the beginning of the world to the present day. Such trends are not sustainable from an environmental point of view. Instead, it is necessary to rethink and reorganize the current plans and agendas.
Short Bio:
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Slobodan N. Vukosavic (Senior Member, IEEE) was born in Sarajevo, Yugoslavia, in 1962. He received the B.S., M.S., and Ph.D. degrees from the University of Belgrade, Belgrade, Yugoslavia, in 1985, 1987, and 1989, respectively, all in electrical engineering. He was with Nikola Tesla Institute, Belgrade, Yugoslavia, until 1988, when he was with the ESCD Laboratory of Emerson Electric, St. Louis, MO. Since 1991, he worked with Vickers Electric Company and MOOG Electric. He is with the Department of Electrical Engineering, The University of Belgrade, and Serbian Academy of Sciences and Arts. He has authored or coauthored more than 100 papers, four textbooks and seven monographs, and has completed more than 40 large R/D and industrial projects. His research interests include digital control, power conversion in renewable energy sources, and power quality. |