In electrolysis, an electric current passes through water, forcing the water molecule to separate into hydrogen and oxygen. The oxygen is released into the air. The hydrogen is compressed to 5,000 psi or 10,000 psi (also called 350 and 700 bar) and stored in steel cylinder-shaped tanks.

When a driver fills a vehicle, he or she enters a PIN on the dispenser and attaches the nozzle to the vehicle. It’s similar to filling a barbeque tank with propane, or putting air in a car tire. The vehicle fills in 3-5 minutes for 350 bar and 7-10 minutes for 700 bar. (At a higher pressure, dispensing is slower to regulate the temperature.)
Several stations in California produce fuel on site through electrolysis, using solar or wind energy. It’s one way to meet California’s regulation SB1505 that requires 33% of hydrogen for transportation be produced from renewable sources.

The station pictured is a Shell station in West Los Angeles. The electrolyzer, compressor and storage tank are on the roof of the canopy, maximizing space at the station.