| abstract |
A composite storage tank system for gaseous hydrogen comprises a composite storage tank having composite wall enclosing a gas storage volume, the composite wall including a metal hydride element, or a metal element capable of forming a metal hydride in the presence of hydrogen, the system further comprising measuring apparatus arranged to measure an electrical characteristic of the metal hydride element or the metal element. The history of leakage of gaseous hydrogen from the tank, the current rate of leakage and the physical condition of the composite wall in the vicinity of the metal or metal hydride element may be inferred from a measurement of the electrical characteristic, without taking the tank out of service as is required in the case of known leaks tests such as a vacuum test, helium leak test or hydrogen sniffing test. |