Renewable energy in Ukraine accounts for 9 per cent. Renewable energy is planned to be developed in the post-war reconstruction. The Swedish experience is suitable for this purpose and it is advisable to apply it. The biggest problem is the conversion of old enterprises to renewable energy sources. The article presents a methodology for assessing the possibility of transition to renewable energy sources.

Ukraine's energy system is in a situation of crisis and development. The system needs stable operation in the face of war and crisis. This requires attracting investments, including foreign ones. To determine the priority areas for investment, it is necessary to model and analyze the benefits and effects of renewable energy types in Ukraine. The aim of the study was to assess the priorities of a model-based representation for determining investment priorities in Ukraine's alternative energy sector. The study employed methods such as analysis, synthesis, morphological analysis, elements of economic and mathematical modeling, and the "Fuzzy TOPSIS" method. The main results include the calculation of indicators for the normalized evaluation of alternatives (renewable energy stations) to select and rank these stations according to a strategy for prioritizing energy sectors for development in Ukraine. The economic effect of implementing the proposed model for establishing investment priorities in Ukraine's alternative energy sector lies in the fact that the use of scenario-based evaluation factors primarily encourages an increase in investment inflows, particularly from foreign investors. The transition of Ukraine’s energy system to a carbon-neutral policy will accelerate the country's path toward sustainable and harmonious development, strengthening Ukraine’s position among countries advancing alternative energy, even under temporary martial law conditions.

The economy of Ukraine is partially destroyed and poses an energy threat to European countries. The article analyzes trends in the development of consumption in Ukraine, and assesses the prospects for development. Energy Ukraine's system depends on fossil fuels. The government sought to diversify risks and ensure sustainable development. The energy consumption market is characterized by a decline and an increase in the use of gas.

The article develops cases for making decisions on the necessary investments in the energy system of Ukraine after the war. We analyze energy consumption trends and justify the need for investment in the nuclear industry, which occupies a large part of the country's energy consumption. A model for assessing and forecasting the energy consumption market has been developed. The model shows an upward trend in oil and gas consumption. Our approach allows us to quantify the net increase in energy consumption in the future.

The paper proposes a new scientific approach to modeling carbon dioxide (CO2) emissions in individual countries, based on the tools of Kohonen self-organizing maps and the provisions of economic theory. This work is based on conducted a comprehensive analysis of wide set of indicators influencing carbon dioxide emissions and decarbonization processes in 40 selected countries for 10 years time span from 2013 till 2022. During clustering these nations using self-organizing maps, 14 key indicators were chosen that cover economic and demographic growth, energy consumption, CO2 emission data, and includes trade of energy recourses for wider analysis and identification of countries with similar decarbonization potential, economic development and trade energy recourses possibilities. This approach exposed distinct clusters of nations with varying decarbonization capabilities and tracked the progress of analyzed countries in terms of CO2 emission changes in dynamic.

The analysis of clustering was focused on identification leaders and followers in decarbonization activities. The leaders cluster includes Sweden, Norway, New Zealand and other countries exhibited leadership in developing a climate-resilient economy among 40 countries. Hence, all countries positioned closer to the leader cluster on the map demonstrated higher efficiency in their decarbonization pathways. Consequently, these properties of Kohonen maps provide a foundation for formulating general recommendations to achieve an efficient and effective low-carbon economy for followers including Ukraine, Kazakhstan and other energy intensive countries.

Distinct countries decarbonization profiles resulting from clustering were used to develop practical recommendations towards estimating and establishing targeted CO2 emission levels for analyzed countries, conducting continued promoting renewable energy utilization, enhancing cross-border energy trade, diversifying energy portfolios, etc. Also, the proposed methodology can be utilized to project future emissions trends for each country based on cluster-specific models and facilitate policy decisions making process related to mitigating carbon emissions.