Future energy systems will have to face the challenge of managing surplus electricity from renewable sources. In this context, technologies like electrolyzers could play a key role since they can convert this surplus into hydrogen. The study aims to develop an energy strategy for the Campania region, in Italy, aligning with 2050 European CO₂ reduction targets. It utilizes detailed bottom-up modeling and dynamic simulations to propose a scenario emphasizing extensive integration of renewable energy sources, particularly using Power-to-Gas technologies to convert surplus electricity into hydrogen for the transportation sector. This approach leads to abating the significant surplus of around 2.4 TWh/year produced by renewables and enables it to cover about 10% of transport sector consumption by hydrogen, boosting the overall share of renewable energy.

The Renewable Energy Directive II introduces renewable energy communities, enhancing energy sharing. However, many existing initiatives, focussing only on electricity, overlook the substantial energy demand in building sector comprising residential and commercial spaces. Energy communities in this sector can leverage district heating and cooling technology for thermal energy sharing, contributing to carbon neutrality by enhancing efficiency and reducing primary energy usage. Advanced strategies such as integrating renewables into heating and cooling grids, sector coupling, and utilising waste heat are key in moving away from fossil fuels. The Campania Region (Italy), abundant in geothermal energy potential, chose a district in which to implement the GeoGRID system. This innovative setup combines a four-pipe district heating and cooling network with an Organic Rankine Cycle plant, tapping into geothermal energy from the Solfatara area. The geothermal fluid’s heat feeds the ORC evaporator and then powers the thermal network, allowing direct heating and domestic hot water supply during winter. A thorough techno-economic analysis assessed the energy potential extractable from the geothermal fluid. Crucial aspects of this study are the evaluation of the energy and environmental efficiency of the system within the renewable energy community framework. Additionally, the paper introduces a methodology applicable for assessing geothermal energy communities on a global scale.