Optimal sizing of energy communities with fair revenue sharing and exit clauses: Value, role and business model of aggregators and users

Energy communities (ECs) are essential tools to meet the Energy Transition goals but, to fully unleash their potential, they require a coordinated operation and design that the community itself may be ill-equipped to manage. Aggregators and Energy Service COmpanies (ESCOs) can perform this support role, but only provided that their goals are aligned to those of the community, not to incur in the agency problem. In this study, we propose a business model for aggregators of ECs, and its optimization problem, accounting for all crucial aspects: (i) alleviating the risk of the agency problem, (ii) fairly distributing the reward awarded to the EC, (iii) estimating the fair payment for the aggregator services, and (iv) defining appropriate exit clauses ruling what happens when a user leaves the EC. A mathematical model is developed, employing several fair game-theoretic reward distribution schemes, some of which are proposed here for the first time. A case study is developed, and results show that the aggregator enables reducing costs by 16% and improving renewable penetration and self/shared consumption by 35%–51% with respect to the base case. Our results suggest that the aggregator fair retribution is around 16%–24% the added benefit produced with respect to the base case, and that stable reward distribution schemes, such as Shapley/Core, Variance/Core or Nucleolus, are stable and recommended. Moreover, the results highlight the unwanted effect that some non-cooperative ECs may have an added benefit without providing any positive effect to the power system. Our work provides a methodology and preliminary results that can help policy makers and developers in tailoring national-level policies and market-offerings.