Proton Exchange Membrane Water Electrolysis as a Promising Technology for Hydrogen Production and Energy Storage

Proton exchange membrane (PEM) electrolysis is industrially important as a green source of high-purity hydrogen, for chemical applications as well as energy storage. Energy capture as hydrogen via water electrolysis has been gaining tremendous interest in Europe and other parts of the world because of the higher renewable penetration on their energy grid. Hydrogen is an appealing storage medium for excess renewable energy because once stored, it can be used in a variety of applications including power generation in periods of increased demand, supplementation of the natural gas grid for increased efficiency, vehicle fueling, or use as a high-value chemical feedstock for green generation of fertilizer and other chemicals. Today, most of the cost and energy use in PEM electrolyzer manufacturing is contributed by the cell stack manufacturing processes. Current state-of-the-art electrolysis technology involves two options: liquid electrolyte and ion exchange membranes. Membrane-based systems overcome many of the disadvantages of alkaline liquid systems, because the carrier fluid is deionized water, and the membrane-based cell design enables differential pressure operation.