Efficient Green Hydrogen Production from Wind Power: A System Design Perspective Regarding Optimal Operating Pressure for Alkaline Electrolyzers

The operating pressure in alkaline water electrolyzers plays a critical role for the efficiency and safety of hydrogen production from wind energy. Higher operating pressures offer the advantage of reduced compression costs, but also increase gas-crossover, leading to potentially explosive mixtures of hydrogen and oxygen and thus impacting system safety. This research investigates the optimal selection of operating pressure to maximize the utilization of fluctuating wind power inputs while also maintaining safety constraints. Based on a comprehensive model of an alkaline water electrolysis plant, lower operating limits are determined as a function of system pressure. Based on the established lower limits, a case study using wind power data over one year is conducted to investigate the impact of selecting the right operating pressure on the economic performance. The study demonstrates that for large electrolysis systems powered by wind energy, the optimal operating pressure is lower than the values typically used in comparable studies from the literature. The results show that operating at intermediate pressures can be beneficial for increasing production. The optimal Levelized Cost of Hydrogen (LCOH) for independent electrolyzer groups is achieved when both are operating at 8 bar. For this plant configuration, the LCOH is calculated to be 9.50 €kg^−-1.