Objectives In order to fully leverage electricity and seawater resources, this paper carries out the thermodynamic analysis and optimization design of an alkaline water electrolysis hydrogen production system for offshore wind power. The focus comprises the impacts of operating pressure, temperature and lye flow rate on the operational characteristics of the system.

Methods Thermodynamic, kinetic and flux balance analyses are carried out to develop a thermodynamic equilibrium model for hydrogen production by alkaline water electrolysis using Aspen Plus software, which is then validated in comparison with the experimental results.

Results The optimum working pressure and temperature of the alkaline water electrolysis hydrogen production system are 9 bar and 70°C respectively, and the optimum alkaline water flow rate is 1,600 t/h. The system energy loss and yield loss increase with the increase of input current density. When the alkaline water electrolysis input current density reaches 3,000 A/m2, the system energy efficiency and yield efficiency are 63.58% and 57.27% respectively, and the system energy loss accounts for 26% of the total energy input, of which the yield loss of the electrolyzer is the highest, accounting for 93.39% of the total yield loss of the system.

Conclusions Through this parameter optimization method, a suitable range of operating parameters can be obtained, providing useful references for the selection of offshore wind power hydrogen production parameters.