To be fair, acceptable and ultimately successful, decentralised energy projects involving technological innovations require engagement with users, local communities and wider publics. Yet relatively few studies have adopted a dynamic, temporal approach to understand how publics are engaged with as projects develop over time. We address this gap by researching three case studies of ‘Smart Local Energy System’ (SLES) demonstrator projects involving combinations of power, heat and transport technologies funded under a UK government programme. Guided by literature on public engagement methods and rationales, as well as how users and communities are framed by stakeholders, we track engagement approaches over time from stages of project initiation to technology deployment. Engagement defined as communication and consultation predominates over participation and community empowerment, with instrumental rationales used to frame publics as consumers enabling technology deployment. Disruptions to engagement attributed to external factors such as the COVID-19 pandemic and BREXIT were interpreted both positively and negatively, including the implications of disruptions for social inclusion and fairness. The potential for SLES to catalyse broader social transformations in a context of environment and climate emergency is discussed.