Liquefaction of hydrogen requires cooling to a temperature of -253 °C and subsequent storage in cryogenic containers. Liquefaction is an energy intensive process and can consume up to 35% of the energy in the stored hydrogen.
The advantage of liquefied hydrogen is its high density compared to compressed gas, which means that more energy can be contained in a given volume. This is particularly beneficial for transportation of hydrogen. Generally, liquefaction of hydrogen is only appropriate where it is produced in large quantities and will be transported in bulk (or over long distances).
Since most hydrogen vehicles have a compressed gas container on board, the liquid hydrogen has to be converted to compressed gas before refuelling the vehicle. This process requires complex infrastructure, involving controlled vaporisation of liquid hydrogen and compression into a compressed gas storage facility.