In this report, we investigate the role of regulatory experimentation as an innovation tool to enable and facilitate the energy transition. Regulation can help to accelerate the adoption of innovative technologies, solutions and business models, thus reflecting the fast-changing environment that digitalisation and decarbonisation bring about, while continuing to empower and protect consumers. Regulators have a range of tools for engaging with and addressing innovation (e.g. regulatory sandboxes, regulatory pilot projects and pilot regulations). We analyse regulatory experimentation initiatives conducted in EU Member States to identify forms of regulatory experimentation adopted, areas of experimentation, stakeholders involved, emerging trends and lessons learned. The analysis, based on the existing literature, desk research and interviews with competent authorities, includes initiatives already implemented at national level, as well as those under development or still in the planning phase. Differences in national regulatory frameworks and a lack of uniform information on the assumptions, requirements, and results of the initiatives, hinder comparisons of national experience. An overview of the main developments, however, may help to show the direction EU Member States are taking and to reflect on the opportunity for providing EU level guidance to support the implementation of regulatory experimentation initiatives at national level.