Hydrogen at 20C and 1 ATM (ambient gas, basically) has a density of 0.083 kg/m³. So, a 1 cubic meter tank (about the size of a large refrigerator) would have .083 kg of hydrogen at ambient temperature and pressure. If you could increase the density (via increasing pressure, for example) 60x, that would be ~5 KG in a 1 cubic meter tank. 60 ATM is about 800 PSI, or about the pressure of a CO2 cartridge. From Wikipedia, though, car companies are trying to amp the pressure way up to 10x that, presumably to get the tank size down or increase the total energy.
thehappypm|1 year ago
https://en.wikipedia.org/wiki/Hydrogen_storage