The European energy market is rapidly changing under the influence of three megatrends that currently drive the transformation of energy sectors worldwide: decarbonization, decentralization and digitalization. These megatrends have stimulated several technical and social innovations in the energy sector, which offer alternatives to the traditional business model of large centralized energy utilities and have the potential to further the goals of the Energy Union. One such example of social innovation in the energy sector are new forms of local energy communities that generate, store and use energy in a collaborative way and hence allow consumers to get involved in the production and storage of energy (“prosumage”) at the local level. New clean energy communities in a changing European energy system (NEWCOMERS) are often democratic and participatory in nature and at the same time characterized by unconventional alliances of actors, the use of innovative and smart technologies and new forms of value creation for their members and society. The NEWCOMERS project aims to investigate which regulatory, institutional and social conditions, at the national and local level, are favorable for the emergence and operation of new clean energy communities. Furthermore, NEWCOMERS will explore how these new clean energy communities meet their members’(i.e. citizens’ and consumers’) needs better than more traditional energy services business models and whether they have the potential to increase the affordability of energy, their members’ energy literacy and efficiency in the use of energy, as well as their members’ and society’s support for the clean energy transition. The ultimate goal of the NEWCOMERS project is to identify the types of clean energy communities that perform best along a variety of dimensions, such as resilience, citizen engagement, security, efficiency and affordability, while being based on sustainable business models that have the potential to be scaled-up.