Small Renewable Energy Community: The Role of Energy and Environmental Indicators for Power Grid

The Clean Energy for all Europeans Package pushes for the diffusion of renewable energy communities, introducing their definition in the European legislative framework. Following this interest, this paper analyses the energy and environmental performance of a renewable energy community composed of two office buildings located in Naples (Italy). Each building has a rooftop photovoltaic plant and one office presents an electric vehicle. The heating and cooling demands of both offices are satisfied by two reversible air to water heat pumps. The offices are connected through an electric microgrid and they are in parallel with a power grid. Buildings and plants are modelled and simulated by means of TRNSYS 17 simulation software. The first analysis has concerned the comparison of the results achieved in renewable energy community configuration and from individual buildings in terms of quantity of electricity imported, exported from/to power grid and consumed on-site. The share of self-consumed photovoltaic electricity rises up to 79% when energy sharing is allowed. The second analysis has been carried out to evaluate the energy and environmental performance of a renewable energy community by means of fixed and hourly varying values for power grid efficiency and emission factors for electricity. The use of time-dependent indicators has led to a lower community primary energy demand and carbon dioxide emissions of 18% and 12%, respectively, in comparison with the scenario in which the fixed parameters have been adopted.