Annotation: The article examines the state and peculiarities of the functioning of the energy system of Ukraine in the modern day and their compliance with the development trends of the world and European energy industry. It was determined that the energy sector of developed countries, in particular the EU, is undergoing a transformation in the direction of decarbonization and increasing the share of renewable energy in meeting production and consumption needs. The priority areas of integration of the domestic energy system into the European space on the eve of the war with the Russian Federation have been identified. The main problems of the functioning of the energy system of Ukraine in the conditions of military aggression by the Russian Federation are revealed.