Optimal Photovoltaic Energy Allocation in Residential Renewable Energy Communities

This paper investigates the optimal allocation of photovoltaic energy within Residential Renewable Energy Communities (RECs) to maximise the economic and operational benefits of collective self-consumption. Developed within the Horizon Europe DEDALUS project, the study addresses one of the key challenges limiting the widespread deployment of RECs: the absence of efficient and equitable methodologies for distributing locally generated renewable electricity among community members. The proposed approach seeks to improve energy sharing while reducing surplus energy exported to the grid and ensuring a fair return on investment for participating users.

The proposed methodology builds upon linear programming optimisation techniques to determine optimal photovoltaic energy-sharing coefficients under both a priori and a posteriori allocation frameworks. Several cost functions are evaluated to balance competing objectives, including minimising community energy costs, reducing energy surplus, improving self-consumption, and ensuring an equitable distribution of economic benefits among REC members. The optimisation framework is validated using real electricity consumption, photovoltaic generation and market price data collected from a Spanish Distribution System Operator (DSO), considering multiple Renewable Energy Community sizes and regulatory scenarios.

The results demonstrate that a posteriori energy allocation consistently outperforms a priori approaches by reducing forecasting uncertainty, increasing self-consumption and improving overall economic performance. Among the evaluated optimisation strategies, quadratic cost functions provide the best compromise between maximising community savings, limiting surplus energy exported to the grid and balancing investment payback across participants. The proposed optimisation framework offers a scalable decision-support tool for Renewable Energy Communities and contributes to the development of more efficient, fair and resilient collective self-consumption schemes capable of accelerating Europe's clean energy transition.