This report presents a summary of findings from ACCTING’s second cycle of experimental studies, which entailed 87 quasi-experimental case studies conducted across thirteen countries between December 2023 and August 2024. Each of the eight research lines explores sustainability and behavioural change within the framework of a specific European Green Deal policy area — including climate change, biodiversity, energy, food, and transport. The Research Line 3 report focuses on what variables influence the outcome of energy community projects involving vulnerable individuals and aiming at reducing energy vulnerability, and what variables in communities influence the behaviour of individuals (at both individual and collective levels) who promote, join and participate in energy communities that reduce energy vulnerability. All reports are available at https://accting.eu/project-deliverables