[solarguy]

Hard to compress, terrible energy density, net energy looser, highly flammable, explosive, hard to store.

There is more hydrogen in a gallon of gasoline, than there is in a gallon of hydrogen, as stored in any simple pressurized tank. Or even in cryogenic liquid hydrogen. Horrible energy density by volume.

And it either comes from natural gas (bad) or is (typically) made on site in the application you describe, by electrolysis of water. Best case scenario, under high pressure, with the good platinum electrodes, under carefully controlled conditions, 70-80% EROEI (Energy Returned On Energy Invested). Under the hood of a car, without the fancy schmancy equipment, you'd be doing very good to exceed 40%.

Hydrogen is a total dead end for automotive use.

Finest regards,

troy