Appropriate management of energy sources is one of the basic undertakings in the energy sector. Climate policy changes and the development of technologies enabling the acquisition of energy in a way to reduce the negative impact on the natural environment lead to diversity in the structure of the energy sources being used. Therefore, it is important to assess the impact of these changes on the development of energy sectors by particular countries. The article contains the analysis of various energy sources utilization by European Union (EU) countries and the assessment of the energy production sector potential, and the development of this potential in relation to changes in the energy sources structure. For this purpose, a multidimensional comparative analysis was used. The data for the analysis are derived from the Eurostat database for the years 2017 and 2019 for 28 EU countries and they concern the use of energy sources such as combustible fuels, coal and manufactured gases, natural gas, oil and petroleum products (excluding biofuel portion), hydro/hydropower, wind power, solar photovoltaic, nuclear fuels and other fuels n.e.c. As a result of the research, it was proved that in most EU countries the changes introduced in the structure of the use of various energy sources, according to EU climate policy, have a positive impact on the development of particular energy sectors.