A comprehensive review on geo-storage of H₂ in salt caverns: Prospect and research advances

The demand for clean and sustainable energy has driven the need for efficient storage. Hydrogen being a carbon–neutral energy carrier, offers a versatile solution. However, reliable large-scale storage is crucial due to renewable energy fluctuations and production challenges. Underground hydrogen storage (UHS) in salt caverns has emerged as a favorable option given its numerous benefits, including high withdrawal capacity, low creation cost, and enhanced safety. This review provides a comprehensive examination of UHS in salt caverns. It begins with an overview of the potential of salt caverns for UHS, comparing them to UHS in porous media. Then discusses potential sites and various research initiatives related to UHS in salt caverns. Detailed attention is given to the integrity of salt caverns for UHS, comparing them to porous media, and a brief discussion on the transport mechanisms of hydrogen in salt caverns is included. Furthermore, the review covers experimental and modeling works concerning salt caverns for UHS. The review reveals that UHS in salt caverns plays a vital role in the decarbonization of the various energy sectors as there are numerous research initiatives in this regard. The various experimental and modelling works prove that salt caverns exhibit high storage integrity for UHS, despite the specific properties of hydrogen. The different salt deformation mechanisms act competitively to prevent significant permeability evolution. Further investigations were recommended to focus on the monitoring and control as well. In conclusion, this review offers a concise and focused understanding of UHS in salt caverns.