Design and performance assessment of an integrated energy system with compressed air and pumped hydro storage

This study proposes a new integrated energy system driven by solar energy with compressed air and pumped hydro storage options, as it aims to produce multiple useful outputs to help achieve a sustainable community. In this regard, a specific location is selected as the Kalgoorlie-Boulder community in Australia for a case study and a potential application. The present system integrates various technologies to provide five key outputs: electricity, hydrogen, cooling, heating and hot water. The integrated system is designed to operate in two distinct modes: charging and discharging. During the charging phase, surplus energy is used to compress air in an underground cavern and for pump hydro storage, which is later released during the discharging phase to meet peak energy demands. The microbial electrolysis cells, using domestic wastewater as feedstock, produce hydrogen at a rate of 0.05 kg/s. The system produces electricity mainly by steam the Rankine cycles and two-stage gas turbines, resulting in a net output of 5366.45 kW during charging and 30,703.4 kW during discharging. It provides 2.39 kg/s of heating, 2 kg/s of cooling, and 50 kg/s of hot water. The current system finally shows energy and exergy efficiencies of 32.05 % and 37.6 % during the charging phase and 56.1 % and 65.9 % during the discharging phase, respectively. • Energy and exergy efficiencies are 32.05 % and 37 % in charging mode, and 56 % and 65 % in discharging mode. • Hydrogen production rate is 0.05 kg/s using the microbial electrolysis cell (MEC) system. • Net electrical power generation is 5366.45 kW in charging mode and 30,703.4 kW in discharging mode. • Heating, cooling, and hot water outputs are 2.39 kg/s, 2 kg/s, and 50 kg/s in charging mode. • Space heating output reaches 77.39 kg/s in discharging mode, with cooling and hot water outputs remaining consistent.