High-Pressure Electrolysis

High-pressure electrolysis, or HPE, is the electrolysis of water, splitting water into oxygen and hydrogen gas by passing an electric current through it, that produces its hydrogen output already compressed to around 12 to 20 megapascals, or 120 to 200 bar, at 70 degrees Celsius. The difference from a standard proton exchange membrane electrolyzer is this compressed output; by pressurizing the hydrogen inside the electrolyzer itself, the need for a separate external hydrogen compressor is eliminated, and the average energy consumption for this internal differential-pressure compression is around 3 percent.