The aim of this report is to provide an overview of the activities, organisation and implications of energy communities as participants across the energy system. It also aims to inform and identify paths for future policy implications and research initiatives. The report explores findings by looking at a wide range of activities, organisational forms, drivers, societal benefits of energy communities and their contributions to renewables expansion. It also analyses the implications of energy communities as new actors for consumers and the energy system. The analysis draws evidence from literature review and 24 case studies of community energy projects as described in the Annex.