Comparative analysis of hydrogen and methanol energy storage systems for large-scale applications: Thermodynamic and economic perspectives

An increase in the share of renewable energy sources is essential for decarbonizing energy systems, while energy storage systems are needed to ensure grid stability. This study designed and analyzed a hydrogen energy storage system (HESS) with hydrogen storage pressures of 200, 350, and 700 bar, and a methanol energy storage system (MESS) from thermodynamic and economic perspectives. MESS showed lower energy efficiency (27.0 %) than the 200-bar HESS (28.6 %) due to compression and reactor heating requirements. However, at a PEMEC capacity of 100 MW, the LCOS of MESS ($0.422/kWh) was 7.7 % lower than that of 200-bar HESS ($0.457/kWh). Sensitivity analysis revealed that MESS exhibited lower cost variability with storage duration changes. Despite its complexity, MESS demonstrated economic advantages for large-scale and long-term storage. This study provides insights into selecting energy storage systems for large-scale applications, advancing the transition to sustainable energy.