Regional Energy Policy Cooperation has now gained political traction in the EU as a tool to advance the EU's energy objectives. Cooperation and coordination is meant to facilitate the convergence of markets and policies, so while the creation of one EU Internal Energy Market remains the goal, regional cooperation is the tool with which to achieve that goal. Cooperation could become the stepping-stone towards the completion of the Internal Energy Market within the European 2030 climate and energy framework and beyond.The Energy Union concept recognises the importance of regional integration. For South East Europe, regional energy policy cooperation is seen as a means to address region-specific challenges such as security of supply, energy imports dependence, affordability, but also to build trust. South East Europe's hitherto untapped or underutilised potential for renewable energy, hydro - also for storage - and the huge potential for energy efficiency improvements offer a great opportunity to solve the region's challenges.This paper was written within the framework of the “Regional Energy Policy Initiatives”, a project by the Centre for European Policy Studies' Energy Climate House. It explores the potential of regional approaches to European energy policies to improve the effectiveness of EU energy policy objectives in South East Europe and the EU at large.