Adiabatic compressed air energy storage system combined with solid-oxide electrolysis cells

Abstract

Green hydrogen from electrolysis using renewable energy is becoming increasingly important and competitive because of the rapid decrease in the price of electricity from solar photovoltaic (PV) and wind power. Electrical energy storage (EES) can reduce the installation capacity of electrolyzers owing to their steady and continuous operation. Adiabatic compressed air energy storage (A-CAES) systems can be effectively combined with large scale solid-oxide electrolysis cells (SOEC) for low-cost production of hydrogen. Although the round-trip efficiency of the power-only A-CAES (70–75%) is lower than that of batteries (90%), the A-CAES system can be used as a combined cooling, heat and power (CCHP) system, providing heat and power to SOEC in order to maximize the energy efficiency of the system. This paper presents a parametric study of an A-CAES system combined with an SOEC system in terms of the energy and exergy analyses. The results show that a medium-temperature trigeneration CCHP A-CAES system in combination with a SOEC system with a compression power of 100 MWh can provide 47.8 MWh of electric power and 63.5 MWh of heat to the SOEC system as well as 9.9 MWh of cold energy from the cold outlet air of the A-CAES.

Keywords

• Adiabatic compressed air energy storage
• Solid-oxide electrolysis cells
• Thermal energy storage
• Round-trip efficiency
• Energy and exergy analysis
• Trigeneration