In economic, technical and political terms, the security of energy supply is of the utmost importance for Europe. Alongside competition and sustainability, supply security represents a cornerstone of the EU's energy policy, and in times of rising geopolitical conflict plays an increasingly important role in its external relations. Within this context, the contributors analyse and explore the natural gas, nuclear, and hydrogen energy sectors, which will be of critical significance for the future of energy supplies in Europe. The book opens with an extensive exploration of the very definition of 'supply security' and moves beyond sector-specific debates to highlight the political sensitivity surrounding energy security. The expert contributors apply a policy perspective, underpinned by theoretical discussion, to economic analysis in order to yield policy-relevant conclusions. They illustrate that the EU lacks a coherent transnational energy policy, that national energy policies fail to match EU goals and that, ultimately, sustainable energy policies, more competition, and better regulation will improve global welfare. Academics and EU policymakers - both at national and international levels - will find that the topical policy recommendations, extensive overview of supply security, and detailed perspectives on the natural gas, nuclear and hydrogen sectors presented herewith constitute an invaluable reference and research tool.