Our study of hydropower regimes in European countries reveals the considerably variable terms of hydropower usage rights, in both their joint obligations and the degree of openness of the competition processes through which these rights are granted. The environmental and economic stakes and liabilities associated with the use of hydropower account for the in-depth public controls in granting these rights. Nevertheless, the strong differences among hydropower regimes in Europe cannot be explained by rational environmental or economic criteria while they bring competition distortion to the common European electricity market. Over the last decade, the European Commission has opened several infringement procedures to prompt the implementation of competitive processes. However, unfortunately, this has not been undertaken with a common 'European' approach, which would ensure similar efforts throughout Member States to open the competition process to access hydropower. The current discrepancies among Member States create obstacles for countries engaged in a competitive renewal process, as there is not a level playing field or a coherent European reference framework. Thus, the heterogeneous state of European hydropower regimes requires significant efforts from the European Commission, and the institutional stakeholders, to stimulate harmonisation. It would help if the Commission Directorates-General started debating the topic and coordinating their action. New, clear steps must be taken to prepare national and regional authorities to harmonise their rules of attribution and to mitigate competition distortions.