The results of the estimation of the annual potential for thermal energy production using heat pumps (HPs) in district heating systems (DHS) for the regions of Ukraine and the country as a whole are given. This study is relevant due to the high level of DHS development in Ukraine, which reaches 52 %. Today, the outdated equipment of DHSs in Ukraine needs significant technological modernization. Also, in the near future, it will be necessary to restore DHSs destroyed as a result of the total destruction of the civil infrastructure by the russian aggressor. The post-war reconstruction of Ukrainian cities has a unique chance to radically update DHSs using renewable energy sources and innovative technologies, including HPs. The authors propose a new methodical approach for the regional determination of the forecast implementation scope of HPs in DHSs. Using this approach, the economically available energy potential of thermal energy production by HPs in DHSs from various low-potential heat sources (LPHS) was determined, both for the regions of Ukraine and for the country as a whole. As of 2020, this energy potential for DHSs of Ukraine is 62.601 million Gcal/year (262.1 PJ/year): 22.2 % is provided by natural LPHS (heat of air (2.2 %), river water (16.9 %), ground and groundwater (3.1 %)) and 77.8 % is provided by anthropogenic LPHS (heat of ventilation emissions of buildings connected to the DHS (43.0%), sewage water (9.7 %), flue gases from boilers and combined heat power plants (14.3 %), cooling water of technological processes (10.8 %)). The calculated energy potentials for the thermal energy production by HPs from various LPHSs for DHSs of 24 regions of Ukraine are presented also. Information from scientific publications, regulatory documents, annual reports of the State Statistical Service of Ukraine and other government agencies used as the initial data for calculations. Approved methods of heat engineering calculations, methods of statistical and calculation-comparative analysis using Microsoft Excel computer software used to calculate and visualize the results. Methodical recommendations for determining the priority and locations for the implementation of HPs in regional DHSs of Ukraine, which developed by the authors of the article, are presented. Bibl. 48, Fig. 2, Tab. 4.

Introduction. The energy sector makes the largest contribution of about 65% of the total amount to greenhouse gas (GHG) emissions in Ukraine. District heating systems (DHS) as an energy subsector are a significant source of GHG emissions as a result of the combustion of fossil carbon fuels (natural gas, coal, petroleum products, peat, etc.).Problem Statement. Due to its obvious advantages, DHS will continue to develop with the use of advanced te chnologies that allow a significant increase in the efficiency and a reduction in heat losses, and accordingly ensure the lowest cost of heat energy for consumers. However, at the moment, no forecast has been made for the dyna mics of Ukraine’s DHS fuel balance, the heat generation structure, and, accordingly, GHG emissions until 2050.Purpose. The purpose of this research is to estimate the impact of structural changes in the DHS on the greenhouse gas emissions.Material and Methods. Publications in scholarly research journals, official documents, statistical data, methods of statistical and comparative analysis have been used. Calculations have been made with the use of the Methodology of the United Nations Intergovernmental Panel on Climate Change (UN IPCC).Results. Changes in the fuel balance and the generation structure of DHS of Ukraine have been forecasted. According to the forecast results, the natural gas consumption will decrease 1.4—2 times, while that of coal will fall 1.4—5.9 times. Petroleum products will not be used in DHS after 2040, but the electricity consumption will increase 7.7—19 times. At the same time, the biomass consumption will increase 2 times, and that of solar energy will grow 77 times, as compared with 2020. In 2050, the GHG emissions from DHS will amount to 3.9—6.9 million tons of CO2-eq., depending on the DHS structural dynamics scenario.Conclusions. The forecast of the structure of Ukraine’s DHS heat energy generation has predicted a 4.4 times reduction in the greenhouse gas emissions by 2050 for the optimistic and 2.5 times reduction for the pessimistic scenario of the DHS development, as compared with 2020.

The decarbonization of the global economy has become a driving force behind the rapid development of wind and solar power plants. This process is also taking place in Ukraine, a signatory to the Paris Agreement aimed at reducing greenhouse gas emissions. The sharp increase in capacities of solar and wind power stations, due to the stochastic nature of their generation, has led to a number of systemic problems in the energy sector, including the significant excess of electricity generated by them. Given the insufficient flexibility of existing power systems and daily load variations, frequency regulation in the grid and power balance maintenance become significantly complicated, necessitating the refinement of existing methods and the application of new ones for their balancing. The purpose of this article is to identify the possibilities and assess the feasibility of the comprehensive application of Power-to-Heat technology along with electrical and thermal energy storage to enhance the resilience of power and heating systems, which also represents a scientific novelty. The conducted analysis and modeling have shown that the use of electric boilers as electric heat generators in Power-to-Heat technology provides much lower investment costs and greater maneuverable capacity compared to heat pumps. Heat pumps in Power-to-Heat technology are justifiably used in existing cooling systems, for example, in warehouses for storing chilled products, or when a large amount of thermal energy is required with minimal electricity consumption. By appropriately selecting the capacities of electric and thermal storage and the power of electric heat generators, it is possible to completely solve the problem of excess electricity from solar and wind power stations without imposing forced restrictions on their output power, thereby avoiding losses, which in the first half of 2021 in Ukraine amounted to no less than 17.2 million euro. This will also ensure the resilience and sustainability of energy systems, reduce fuel consumption by district heating system boilers, leading to a decrease in greenhouse gas emissions. Bibl. 63, Fig. 8, Tab. 2.

An improved model of mathematical programming is proposed for the study of directions and optimal parameters of the technological renewal of energy system elements operating in energy associations, for the distant perspective and taking into account the perspectives of these elements. The model is a combination and, at the same time, a separate case of two models: a model of a hierarchical controlled quasi-dynamic system and a stochastic quasi-dynamic model of the economic and technological impact of the life cycle of innovative technologies. The main difference of the proposed improved model is the explicit consideration of the influence of economic and technological indicators of the development of the national economy and production, presented in the form of stochastic quasi-dynamic functions. The conducted test calculations confirm the adequacy of the proposed model, the perspective of applying this approach and further development of the model to achieve the necessary levels of detail in the forecast scenarios of the development of energy systems of Ukraine. The performed test calculations made it possible to obtain numerical estimates of the potential that can be achieved by improving the model of long-term technological renewal of power system components. Consideration of the influence of economic and technological indicators of the development of the national economy and production in the form of stochastic quasi-dynamic functions expands the tools and possibilities of obtaining high-quality predictive scenarios of the development of energy systems in Ukraine. The use of efficiency coefficients LCOE, LCOS and LACE, which are widely used in modeling the development of energy systems, increases the quality of the conclusions obtained. Examples of calculations of values of parameters of power system components under different modes of use are given. Keywords: long-term technological renewal of power system components.