Retrospective application of legal rules in the European Union: recent practice in the energy sector

The continual availability of energy is economically and socially essential, but is primarily reliant on private operators and investments to be maintained and developed. Investments in the energy sector are typically highly capital intensive and require long payback periods. This in turn calls for legal and regulatory stability for such investments by the legislator. While changes to laws are inevitable, such changes should be implemented prospectively and take into account the legitimate expectations attached to existing investments. In this article we analyse the recent practice of the EU to retrospectively apply legal rules in the energy sector. Our research shows that it has been common practice of the EU to grant transitional periods and grandfathering rights to allow market participants to adapt to the ‘new rules of the game’. However, while this represents common practice, our research shows that this practice is applied with discretion and can even be misused in the pursuit of political objectives, violating established legal principles including legitimate expectations and legal certainty.