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 Safety concerns Costly tanks |
| 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 Safety concerns Costly tanks |
| 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 |
