In this ground-breaking book, Joerg Radtke offers for the first time within research, a comprehensive insight into the range of organizational structures of community energy projects in Germany and their contribution to the Energiewende. Based on nationwide quantitative survey data and in-depth analyses of selected case studies of solar, wind and geothermal projects, Radtke documents the social structure and motivations of participating citizens. He examines new forms of material participation, community building and co-determination within the mostly volunteer-led community energy projects based on the civic engagement patterns of active "green citizens". The author identifies a new form of individualistic participation and collective modes of action in line with new types of project-oriented participation between business, politics and civil society within sustainability transformation processes of the early 21st century.