Optimal Investment and Fair Sharing Rules of the Incentives for Renewable Energy Communities

Abstract

The focus on Renewable Energy Communities (REC) is fastly growing after the European Union (EU) has introduced a dedicated regulation in 2018. The idea of creating local groups of citizens, small- and medium-sized companies, and public institutions, which self-produce and self-consume energy from renewable sources is at the same time a way to save money for the participants, increase efficiency of the energy system, and reduce CO$_2$ emissions. Member states inside the EU are fixing more detailed regulations, which describe, how public incentives are measured. A natural objective for the incentive policies is of course to promote the self-consumption of a REC. A sophisticated incentive policy is that based on the so called 'virtual framework'. Under this framework all the energy produced by a REC is sold to the market, and all the energy consumed must be paid to retailers: self-consumption occurs only 'virtually', thanks a money compensation (paid by a central authority) for every MWh produced and consumed by the REC in the same hour. In this context, two problems have to be solved: the optimal investment in new technologies and a fair division of the incentive among the community members. We address these problems by considering a particular type of REC, composed by a representative household and a biogas producer, where the potential demand of the community is given by the household's demand, while both members produce renewable energy. We set the problem as a leader-follower problem: the leader decide how to share the incentive for the self-consumed energy, while the followers decide their own optimal installation strategy. We solve the leader's problem by searching for a Nash bargaining solution for the incentive's fair division, while the follower problem is solved by finding the Nash equilibria of a static competitive game between the members.