In SONNET, we investigate the development of the SIE-field called ‘participatory experimentation and incubation’, i.e. multi-actor, collaborative formats that aim to experiment with and/or try out novel energy solutions in specific (local and temporal limited, project-like) settings. This report analyses formats that bring together actors from different societal spheres to collaborate (rather than to have a dialogue only) in a project-like setting. To qualify, a collaboration needs to be considered by at least one of the actors as an ‘experiment’ meaning that it aims at testing, investigating or trialling a specific solution and/or clearly aiming at learning from putting certain solutions in practice. To be included in this report, the experimentation clearly focuses on energy topics and takes place in Germany. Although terms and concepts are often not clearly defined, we could distinguish and trace the developments of at least five collaborative multi-actor experimentation formats during the last twenty years.