Energy communities are non-commercial entities that organise collective ownership around a variety of activities in the energy sector. They are based on open and voluntary participation and are under effective control of citizens, local authorities or smaller businesses whose main activities do not lie in the energy sector. [1] Their purpose is to provide environmental, economic or social benefits to their members or the local community rather than generate financial profits. The energy community concept is defined in the Renewable Energy Directive (RED II) and the Internal Electricity Market Directive (IEMD), which set a regulatory framework for renewable energy communities and citizen energy communities in the EU. Energy communities may engage in the generation, distribution, supply, consumption, aggregation, energy storage, energy efficiency services / charging services for electric vehicles, or provide other energy services to their members or shareholders. In this briefing, we primarily focus on RECs (Renewable Energy Communities) and CECs (Citizens Energy Communities). Other concepts with a broader scope, including more general collective energy actions, are not in primary focus (yet mentioned as they can also positively impact energy justice/energy poverty alleviation).