Renewable energy communities are catalysts for social innovation, involving citizens in energy actions and the enhancement of local resources. Therefore, this document defines a model to analyze and optimally size energy systems serving renewable energy communities. The proposed and replicable model has been adapted for the economic feasibility analysis of a renewable energy community in the municipality of Tirano (Northern Italy). An energy audit was conducted for identification, covering electricity production and consumption within the primary substation perimeter and the thermal energy needs of the existing district heating network. Technical characteristics were determined for the energy conversion systems serving the renewable energy community: an organic Rankine cycle biomass cogeneration plant, a mini-hydro plant, and a distributed photovoltaic system.

Additionally, various scenarios were identified in terms of cogeneration operation modes, photovoltaic penetration, and the economic value of thermal energy. The results demonstrate that increasing the peak photovoltaic power from 4.22 MW to 5.22 MW raises the annual renewable electricity production by 10.1%. Specifically, the simple payback period ranges between 4.90 and 4.98 years, and the net present value ranges between 12.4 and 13.3 million EUR for cogeneration operating at full power, assuming the thermal energy available from the cogeneration unit is sold at 49.2 EUR/MWh. These outcomes demonstrate the economic feasibility of wood-biomass-based renewable energy communities, which can help expand the contribution of renewable technologies beyond photovoltaics.