The growing use of renewable energy sources (RES) in the electricity and heating sectors as well as in the transport industry is one of the key factors affecting the long-term energy security of the EU. In line with this research hypothesis, the aim of the article is to analyse the changes that have been taking place in the EU energy system under the influence of the development of RES technologies and their impact on the geostrategic dimension of EU energy security. The starting point is to analyse trends in the use of RES in the EU against global trends and the underlying determinants. How big a role does the EU climate and energy policy play in increasing the use of RES in EU countries? How big is the influence of geo-strategic or economic factors? With regard to the theoretical framework – the geostrategic dimension of energy security – the article characterises the impact of trends in energy use in the EU on the ‘constant availability of energy in various forms’, especially by 2030. This perspective takes into account the current framework of EU climate and energy policy.