Energy Security in The European Union

The aim of the article is to present a practical and methodological approach to assessing the energy security of European countries, with particular focus on states with coal-dependent energy systems and on finding balance between ensuring energy security, diversification of energy resources and environmental protection. As energy security means technically reliable, stable, cost-effective and environmentally balanced supply of energy resources to satisfy the needs of the economy and the population, the author proposes an indicator that takes into consideration different components, and can be a helpful tool in designing energy policies. The article also discusses using the energy potential of closed coal mines.