The energy sector, particularly that related to renewable energy, is growing rapidly. The analysis of factors influencing the production of electricity from solar radiation is important in terms of the ever-increasing number of photovoltaic (PV) installations. In Poland, the vast majority of installed PV capacity belongs to prosumers, so a comparative analysis was conducted for two domestic installations, one in southern Poland and the other located in central Poland. Operating conditions were compared, specifically with regard to irradiance, outdoor temperature and the calculated temperature of photovoltaic cells. The specific yield was then compared in daily, monthly and annual statements. The effects of the previously mentioned parameters on the energy yields of the two installations were considered. The installation in southern Poland in 2022 produced 5,136.6 kWh, which corresponds to a specific yield of 1,019.17 kWh/kWp, while the energy production of the installation in central Poland was 4,248.9 kWh, which corresponds to a specific yield of 965.67 kWh/kWp.

Energy storage is an increasingly vital aspect of the energy sector in Poland due to the growing prevalence of renewable energy sources. Its primary goal is to support the uptake of renewable energy in the country’s energy mix. The article presented here analyzes the economic potential of buying and selling electricity on the Intra-Day Market and the Day-Ahead Market of Towarowa Giełda Energii SA (Polish Energy Market: TGE) in terms of energy storage. In four scenarios, energy was either bought and sold on the DAM/IDM or bought on one market and sold on the other to identify the most favorable case. Two four-month periods in 2021 and 2023 were examined. An analysis was carried out on a lithium-ion storage facility that has a two-hour charging cycle for energy storage. A methodology was proposed to identify the two highest and two lowest energy prices for imposing constraints on the purchase and sale times. The time of day when these prices occurred was also analyzed. The annual and periodic profits that can be obtained by purchasing and selling stored energy were calculated. The calculations and analyses facilitated inter-market comparison. Energy storage payback time was computed, and investment profitability was examined. The final section presents conclusions, opportunities, and suggestions for further research in this area.
As calculated, the most profitable case after taking efficiency into account was the case of purchase at IDM and sale at DAM in part of 2023: 18,751.61 [EUR/MWh capacity]. In comparison, the highest value for 2021 was obtained for the case of sale and purchase on IDM, with a profit of 7531.23 [EUR/MWh capacity].

Accelerating the transition of the energy sector to ecologically clean energetics using renewable energy technologies will ensure the security of the energy sector of the European Union based on highly energy-efficient and cost-effective technologies for generating heat and electricity. The aim of the study is to assess the economic and ecological aspects of the implementation of renewable energy technologies in Ukraine based on the analysis of trends in the transformation of both the global and the European energy sector. The approach proposed in this article makes it possible to reasonably determine the prospects for the use of environmentally safe energy-saving technologies using renewable energy sources. The analysis of the economic and environmental aspects of energy production based on renewable energy technologies, the condition of development and directions of transformation of the European energy sector is illustrated on the basis of a comprehensive assessment of the efficiency of the use of energy- and resource-saving, environmentally safe and cost-effective innovative technologies of non-traditional and renewable energy sources. This is achieved through the use of a comprehensive generalized dimensionless criterion of energy- ecological-economic efficiency of innovative technologies with the aim of increasing the level of energy-economic efficiency and environmental safety of the energy sector. According to this approach, it is determined that the effective integration of a certain energy- and resource-saving, environmentally safe and economically efficient innovative technology using renewable sources in Ukraine is possible.