Since the beginning of European integration, external energy policy is a key competence of EU Member States. This paper argues that throughout the past decade national prerogatives have been gradually eroding and that the Commission has played a key role in the supranationalization of the field. To investigate this process, the paper analyzes developments in compliance governance as an indicator of the relative power between the Commission and the Member States. In two country examples and one on new EU energy legislation, it finds that the Commission, utilizing a novel compliance instrument that is best described as ‘real-time compliance’, has substantially extended its powers in the external energy realm. This is surprising in two respects. Empirically, the Commission has gained competences in an area traditionally dominated by Member States keen to protect their sovereignty. Theoretically, the expansion of Commission powers has been caused by neofunctionalist integration dynamics that have arguably been sidelined in post-Maastricht Europe.
