Thermodynamic performance study of hydrogen-oxygen combined cycle with high-pressure proton exchange membrane electrolysis cell for hydrogen energy storage

As a competitive energy storage method, hydrogen storage plays a vital role in improving the utilization of renewable energy and reducing carbon emissions. This paper proposes a novel hydrogen energy storage (HES) system with the goal of clean, efficient and simple structure. The system consists of high-pressure proton exchange membrane electrolytic cell (PEMEC) and hydrogen-oxygen combined cycle (HOCC). No hydrogen compressor is used in this system, and water is recycled. Aspen Plus and embedded Fortran are used for system simulation. Based on the simulation results, the system was evaluated by energy, exergy, and sensitivity analysis. The research results show that under the design conditions, the system's round-trip thermal, exergy, and electrical efficiency are 86.25%, 40.87%, and 38.25%, respectively. The energy storage density can reach 20.35 kWh.m(-3). Besides, the variation law of system performance with parameters is also obtained. PEMEC operating pressure, current density, turbine inlet pressure, and combustion chamber water injection flow rate were considered as the main influencing parameters. Increasing the operating pressure of PEMEC can effectively increase the energy storage density. Current density mainly affects hydrogen production rate and charging time. Increasing turbine inlet pressure can improve system efficiency. The water injection flow rate mainly affects the turbine inlet temperature, and the increase in water injection flow will lead to a decrease of discharge efficiency. In summary, this study of a new hydrogen energy storage system provides theoretical guidance and a new idea for the application of hydrogen energy storage systems.