We review innovation by citizen users in the early phases of small-scale renewable energy technologies (S-RET) development and examine user innovation and peer assistance in the later phases of S-RET diffusion. Further, we assess research user motivations, diffusion pathways, and peer intermediation while paying particular attention to how the forms of innovative citizen energy communities are changing.

Citizen users play important roles in the acceleration phase of energy transitions. Widespread diffusion requires not only the adoption, but also adaptation, reconfiguration and intermediation of S-RETs. New Internet-based energy communities have emerged and have come to act as key user-side transition intermediaries, helping to expand the markets for S-RET beyond enthusiasts and environmentalists to mainstream consumers.