Storage is a vital factor in the commercialisation of fuel cells as a safe, efficient and energy dense way of storing hydrogen will greatly improve the viability of fuel cell technology, particularly for automotive applications. Hydrogen can be stored in any state; as a solid, a liquid or a gas.
More information about hydrogen storage can be found in this document from the International Energy Agency.
|State||Storage Mechanism and supply mechanism||Advantages||Disadvantages|
|Gas||Pressurised carbon fibre composite gas tank up to 700 bar||Commercially available||Energy required for compression|
Energy from fossil fuels usually used to produce hydrogen
Tanks are bulky and must be cylindrical
|Liquid||Cryogenic tank at -253°C||Commercially available|
Excellent gravimetric and volumetric hydrogen capacity at low pressures
|30-40% energy loss to cool to cryogenic temperatures|
1%/day losses from boil off
|Solid||Chemical hydrides heated to <100°C to decompose and release hydrogen||Excellent gravimetric and volumetric hydrogen capacity|
Safe, easy to handle
|In the early development stages|
Energy required for off-board regeneration
Harmful by-products must be removed from the impure hydrogen gas stream