Design and economic analysis of high-pressure proton exchange membrane electrolysis for renewable energy storage

The proton exchange membrane (PEM) electrolysis with a high-pressure cathode can help avoid the utilization of a hydrogen compressor and improve the efficiency of hydrogen transmission. The economic analysis of the entire process from hydrogen production to transportation was conducted in this study, and the advantages of high-pressure PEM electrolysis were proved. The economic analysis has also illustrated the influence of the cathode pressure and membrane thickness involved in PEM electrolysis on the energy consumption and capital expenditure of the electrolyzer from the perspectives of hydrogen permeability, ohmic impedance, and structural design. Although the output pressure of hydrogen is increased several tens of times, the proper structure and unchanged thickness of the membrane can help satisfy the strength and safety requirements of the electrolyzer simultaneously. In addition, the energy consumption and cost increase associated with the high-pressure electrolyzer can be limited to an acceptable range. The impact of the renewable energy scale on the decision and selection for PEM or ALK is also analyzed; PEM has an advantage over ALK in large-scale renewable energy hydrogen production scenarios because of its own wider upper and lower load limits compared to those of ALK.