PEM Fuel Cell

The proton exchange membrane (PEM) fuel cell uses a solid polymer electrolyte that conducts protons while blocking electrons, forcing current through an external circuit. Low-temperature PEM stacks run at 60 to 80 degrees Celsius with electrical efficiency near 50 to 60 percent, fast startup, and high power density, which is why they lead marine fuel cell demonstrations. They demand high-purity hydrogen because carbon monoxide above roughly 10 ppm poisons the platinum catalyst. The Sea Change passenger ferry in San Francisco Bay runs a 360 kW Cummins Hydrogenics PEM system with a 100 kWh battery buffer, the first commercial hydrogen fuel cell vessel in the United States.