The issue of energy security was the subject of research in the 1970s when the oil crisis of 1973 significantly affected the economic stability of hundreds of companies and ordinary citizens in the United States and Western Europe. One of the first researchers of energy security was Mason Willrich who, considering the impact of energy on international politics, national security, the world economy, and the environment in the world, drew attention to the issues of “security of supply” and “security of demand” as fundamental to ensure energy security. The concept of “energy security” involves the comprehensive implementation of political, economic, environmental, technological, and social measures to strengthen the internal subjectivity of the state and limit opportunities for external influence. Subsequently, numerous researchers have expanded the understanding of energy security to environmental sustainability and energy efficiency). The presented scientific work is focused on the analysis of state management decisions for ensuring the energy security of Ukraine. The authors also trace vulnerabilities in various energy systems, including energy infrastructure, energy services, and renewable energy sources. The decline in energy demand due to the COVID-19 pandemic in Ukraine has created a dilemma: state support for renewable energy production (RES), which generates rising producer prices, or reduced energy intensity of GDP and stimulated production of cheap nuclear energy. A comprehensive scientific analysis of the solution to this dilemma is the purpose of the presented work.

It is worth mentioning that despite of the decrease of coal generation in the energy mix, the fuel remains crucial for energy sector stabilizing the energy system and securing the energy supply in Poland as well as has a positive impact on the energy security of the European Union. The development of renewable energy will be possible with conventional energy compensating the unstable operation of renewable energy sources as climate conditions in Poland do not allow for the sustainable usage of renewable energy sources and thus, their effective utilization. The modernization of 200 MW energy generating units as well as the possible construction of 2–3 similar units will enable the stabilization of the amount of electricity in the transmission grid. The modern and modernized 200 MW energy generating units are able to maintain grid operation if needed and it will be easier to phase them out gradually as prosumer energy and energy storage technologies are being developed. Due to the held and planned general and additional generation capacity auctions for years following 2020, we are assured that despite the substantial increase of distributed generation sources in Poland’s energy mix, the electricity supply to end-users will be stable and safe.