Energy communities foster solar energy diffusion and distributive justice: Insights from a System Dynamics transition model

The diffusion of residential renewable technologies depends not only on technology costs and incentives, but also on interactions among technologies, household decisions, institutions, and access to collective business models. Existing transition models rarely combine these elements while evaluating their distributional implications. This study develops a socio-technical System Dynamics model of the Swiss residential sector to examine the long-term co-adoption of photovoltaic systems and heating technologies under heterogeneous cantonal regulations and alternative energy community designs. The model represents household adoption decisions and feedback involving public authorities, electric utilities, policy incentives, and electricity prices. Results show that the adoption of photovoltaic systems and heat pumps is strongly interlinked, indicating that policies addressing both technologies jointly can better account for their interdependence in transition pathways. Enabling energy communities increases photovoltaic deployment, particularly in multi-family buildings facing structural and economic barriers to individual adoption. Under the modeled incentive, tariff, and participation conditions, virtual energy communities also improve the two distributional indicators evaluated in the study by expanding access to decentralized electricity and reducing average levy payments for households in buildings without on-site photovoltaic systems. These findings show how energy-community regulation can influence technology diffusion and selected monetary and access-related distributional outcomes, while emphasizing that the effects depend on policy design and modeled assumptions.