Fast-cycling salt cavern storage

Salt caverns are artificial cavities in underground salt formations created by the controlled dissolution of rock salt through the injection of water, which returns to the surface as brine and must be disposed of in an appropriate manner. Salt caverns are suitable for the storage of pure hydrogen due to the low cushion gas requirement (typically around 30% of capacity), the high sealing capacity of rock salt and the inert nature of the salt structures, which limits contamination of the stored hydrogen. The geographical availability of salt caverns is limited. Salt cavern storage is considered to be flexible and would allow several cycles of gas injection and withdrawal per year. However, ongoing research on hydrogen storage in salt caverns is still aimed at demonstrating safe operating limits when subjected to rapid cycling with rapid pressure changes. Most knowledge of the effects of cyclic stress regimes on fracturing and fault slip comes from studies of underground natural gas storage, and there is limited data on the effects of hydrogen, which is needed.