Energy, environmental and economic analysis of a Renewable Energy Community

European policies are focusing more attention on Renewable Energy Communities (RECs) recognising their pivotal role in energy and climate goals aimed to reach the energy transition. These targets determine great opportunities for the activities related to the renewable energy production, supply, distribution and sharing managed altogether by citizens in partners with local authorities and small enterprises. More precisely, citizens are becoming more responsible for their own energy consumption assuming the active role of prosumers in the energy markets. Within this framework, European Commission launched the Clean Energy for all Europeans Package, a set of directives aimed to “redefine” the European energy sector thanks to the push to renewable energy sources exploitation, the energy efficiency measures promotion and the renovation of electricity supply and governance regulations. In particular, one law of this package, that is the recast of the Renewable Energy Directive (RED II), which came into force in December 2018, provided for the first time a formal definition of a renewable energy community as set of energy end-users that decide to make common choices to meet their energy needs with a sharing approach through renewable-based distributed generation technologies. In order to define the energy, economic and environmental advantages deriving from this new entity, REC, this work proposes a techno-economic analysis of a small REC composed of two office buildings located in Naples (south of Italy). Each building is equipped with a photovoltaic plant (9 kWEl and 14.25 kWEl peak power) is installed and one office is provided with an electric vehicle charging station of charging station with a capacity of 3.3 kWEl able to charge an electric vehicle with a nominal electric storage of 30 kWh, a specific consumption of 0.173 kWh/km in Direct Current and a daily distance covered of 120 km. The heating and cooling demands of both offices are met by two reversible air to water heat pumps. Buildings and plants are modelled and dynamically simulated trough TRNSYS 17 simulation software with 1.5 min time-step. A smart control system ensures that each office primarily self-consumes the electricity produced by the own photovoltaic plant and then the surplus electricity is shared with the neighboured office. The photovoltaic plants are in parallel with the external power grid and in the hours in which a surplus or deficit of electricity occurs, it is imported to or taken from power grid. Thus, the energy, environmental and economic performance of REC has been determined and they are compared to those of individual buildings (not grouped in REC configuration) in terms of quantity of electricity imported, exported from/to power grid and consumed on-site. The economic analysis has been carried out by taking into account the current economic support mechanism defined in RED II directive that amounts to 110 €/MWh for each MWh of electricity self-consumed within community. The results highlight that the share of the electricity exported to power grid substantially reduces and the quantity of self-consumed electricity increases when the REC configuration is considered. The share of self-consumed photovoltaic electricity rises up to 79% when energy sharing is allowed and the maximum monthly economic income for REC amounts to 219 €/month.