Thermodynamics analysis of a hybrid system based on a combination of hydrogen fueled compressed air energy storage system and water electrolysis hydrogen generator

In front of the opportunity of the rapid development of renewable energy power generation, energy storage is playing a more important role in improving its utilization efficiency. In this paper, a hybrid energy system based on combination of hydrogen fueled compressed air energy storage system and water electrolysis hydrogen generator is proposed. The superfluous renewable energy power is charged by compressing the air and/or producing hydrogen through water electrolysis. A hydrogen combustor is introduced to raise the air temperature in the discharging process. A thermodynamic model of the proposed system is built. Energy and exergy analysis found that under the design condition, the proposed system can achieve a round trip efficiency of 65.11%, an exergy efficiency of 79.23%, and an energy storage density of 5.85 kWh/m3. The exergy loss of water electrolysis hydrogen generator and hydrogen combustor rank in the top two of all components. Sensitivity analysis indicates that the outlet temperature of hydrogen combustor and specific energy consumption of water electrolysis hydrogen generator are the crucial influencing factor of system performance.& COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this paper, a hybrid energy system based on a combination of hydrogen fueled compressed air energy storage system and water electrolysis hydrogen generator is proposed to improve the utilization efficiency of renewable energy power generation. The system stores excess renewable energy by compressing air and/or producing hydrogen through water electrolysis, and introduces a hydrogen combustor to increase the air temperature during the discharging process. A thermodynamic model is built and energy and exergy analysis show that the proposed system can achieve a round trip efficiency of 65.11%, an exergy efficiency of 79.23%, and an energy storage density of 5.85 kWh/m3. The water electrolysis hydrogen generator and hydrogen combustor have the highest exergy losses among all components, and sensitivity analysis identifies the outlet temperature of the hydrogen combustor and specific energy consumption of the water electrolysis hydrogen generator as crucial factors influencing system performance.