On the eve of World War I, Winston Churchill, as the first lord of the Admiralty, converted the Royal Navy from coal to oil. Consequently, a shift emerged in imported fuel dependency, from Welsh Coal to Iranian oil. Then Churchill declared, “Safety and certainty in oil lie in variety and variety alone”, which in modern terms is diversification of energy supplies. Nowadays, energy security is becoming a central concern for the European states given the increasing demand associated with economic growth and diminishing indigenous hydrocarbon resources. Nevertheless, not only necessity of multiple supply sources, but also climate change, competitiveness in energy markets and prices hikes are of utmost concern for the EU. The range of issues researched in this dissertation is expansive as it employs a new, dual approach to energy security: namely, security of supply and environmental objectives of the European states. In this sense, the project is timely and will be very beneficial for young researchers and professional as it assesses variety of approaches and challenges to the EU’s energy security and encompasses literature in English, Russian, Turkish and Azerbaijani.