Abstract

Abstract
The Renewable Energy Communities (RECs) and self-consumption frameworks defined in Directive (EU) 2023/2413 and Directive (EU) 2024/1711 are currently being integrated into national regulations across EU member states, adapting legislation to incorporate these new entities. These regulations establish key principles for individual and collective self-consumption, outlining operational rules such as proximity constraints, electricity sharing mechanisms, surplus electricity management, grid tariffs, and various organizational aspects, including asset sizing, licensing, metering, data exchange, and role definitions. This study introduces a model tailored to optimize investment and energy-sharing decisions within RECs, enabling multiple members to invest in solar photovoltaic (PV) and wind generation assets. The model determines the optimal generation capacity each REC member should install for each technology and calculates the energy shared between members in each period, considering site-specific constraints on renewable deployment. A case study with a four-member REC is used to showcase the model’s functionality, with simulation results underscoring the benefits of CSC over ISC. © 2025 by the authors.

Abstract
Deploying renewable energy communities, self-consumption and local energy markets are one of the ways to contribute to the energy system decarbonization by increasing the renewable energy share in the production mix and contributing to a better local balancing. However, how collective self-consumption structures are regulated has a direct impact on the flexibility of the energy sharing mechanisms and business models that can be set up. This paper compares and discusses how the European Union directives on self-consumption have been transposed to the national regulations of Portugal, Spain and France, providing a detailed regulatory discussion on the definition of basic concepts such as individual and collective self-consumption and renewable energy communities, proximity rules among members, energy sharing mechanisms and energy allocation coefficients, how the energy surplus is managed in each case, or how the grid access tariffs are modified to account for the self-consumed energy. The study highlights that dynamic allocation coefficients provide significant advantages for collective self-consumption by improving energy allocation efficiency, enabling advanced business models, and facilitating the integration of local energy markets, as it is the case in Portugal and France, while their absence in Spain limits these opportunities. The work also highlights the trade-off between flexible energy sharing and implementation complexity, and the role of digital tools to operationalize energy communities. Suggestions on potential regulatory improvements for all countries are also proposed. © 2025