Hydrogen is a powerful energy carrier with a high energy density: 1 kg of hydrogen is equivalent to 3 kg of petrol.
H2 is better known in its gaseous state for mobility applications. Thanks to its lightness and low density, it can be compressed for use, usually to 700 bar for light vehicles and 350 bar for heavy mobility applications.
Liquid hydrogen also offers advantages for mobility since, in this state, 1 kg of hydrogen is equivalent to 4 kg of petrol. Liquefying H2, on the other hand, requires it to be cooled and stored below its condensation point, at -253°C.