The purpose of this research is to measure how well the EU has balanced two of the stated primary aims in their energy policy strategy; those of sustainability and supply security. The central research question is "How effective is EU energy policy strategy in balancing the conflicting/complementary aims of sustainability and supply security?" The focus in particular is on the two problems of climate change and energy scarcity and how the EU has responded to these conceptually in terms of policy initiatives and more concretely in implementation. Three theories are employed to conduct this research. In order to analyse the energy scarcity aspect of this research critical geopolitics and in particular the scarcity model is used. Neo-Gramscian analysis is used as a means to describe the emergence of the powerful EU climate regime. Ecological modernization theory is used to analyse the way in which the EU has approached the aim of energy sustainability and how this in turn affects the approach to supply security. The study concludes with policy recommendations based on major findings.