ACAES systems to enhance the self-consumption rate of renewable electricity in sustainable energy communities

This paper aims to evaluate the optimal configuration of an Adiabatic Compressed Air Energy Storage (ACAES) system designed to achieve the best matching between power production from non-programmable Renewable Energy Sources (RES) power plants and power demand from final users. The electrical energy demand of a small town, with a maximum power load of about 10 MW, has been considered as case study. The electrical energy can be supplied by both a photovoltaic (PV) power plant and the grid. For the ACAES system, different sizes for compressor, turbine, thermal energy storage (TES) system and air storage reservoir have been evaluated by varying the air mass flow rate of turbomachines and the charging and discharging duration times, to enhance the share of the PV energy supplied to the end user. The best performance is achieved with a PV power plant rated at about 35 MW and an ACAES section characterized by a compressor/turbine rated power of about 25-35% of the maximum power load of the end user, with a charging time of about 10 hours and a discharging time of about 20 hours. The average round-trip efficiency of the ACAES system is around 70%. On the overall, the integrated PV-ACAES system allows to cover 66% of the yearly electrical energy demand.