Sustainable energy trading and fair benefit allocation in renewable energy communities: A simulation model for Portugal

The transition to a decentralized and decarbonized energy system has accelerated the adoption of renewable energy communities (REC), where prosumers share energy locally to enhance self-sufficiency and reduce electricity costs. Conventional models used in REC studies generally assume monetary energy transactions, where those with deficit generation financially compensate members with surplus energy. This study addresses a gap in the literature by proposing a novel energy management model for a Portuguese REC, optimizing socially conscious energy trading without internal monetary compensation. A community of 10 households with photovoltaic generation, with and without battery storage, and a tertiary building (TB) is analyzed over a 25-year investment horizon, incorporating realistic electricity prices, taxes, and the evolution of consumption and generation. The study evaluates three key aspects of REC: technical performance, economic viability, and environmental impact. Results show that prosumers can achieve € 2523 annually from selling surplus electricity to the TB rather than to the grid. A self-sufficiency of 80 % and a reduction in CO2 emissions can be achieved in the REC scenario with the highest battery capacity. Findings reveal that investing in a REC is more profitable than individual self-consumption or non-investment, with potential net present values reaching €14,806 and internal rates of return of 24 %. A fairness index calculation shows that the new benefit allocation model outperforms existing ones in ensuring equity among members. This simulation study provides valuable insights for prosumers and policymakers, demonstrating the economic and environmental advantages of REC in accelerating the clean energy transition.