Aquifer thermal energy storage for decarbonising heating and cooling energy supply in southern Europe: A dynamic environmental impact assessment

Scientific research has demonstrated the potential of Aquifer Thermal Energy Storage (ATES) in heating-dominated countries. Nevertheless, ATES could play a significant role in supporting the decarbonization of cities in Southern Europe by providing sustainable heating and cooling for buildings. This work proposes a comparative environmental impact assessment of two alternative electric-driven heat pumps activating a small-scale district heating and cooling network in Rome (Central Italy). The traditional system is an air-source heat pump, while the proposed solution includes a water-to-water heat pump coupled with ATES. Based on the results of dynamic simulations, a time-dependent environmental analysis is conducted, accounting for the temporal variability of the carbon dioxide emission factor of the power grid and the heat pumps' heat source temperature over the system's fifteen-year lifetime. The forecast of the Italian power grid emission factor is based on hourly historical data, while three different climate files, representing historical, mid-term, and long-term future climatic conditions, are used to simulate the traditional system to account for the variability in air-source heat pump performance due to climate change. The results from the time-dependent assessment highlight the environmental benefits of the proposed solution, which exhibits a 22 % lower Total Equivalent Warming Impact compared to the traditional system.