Underground Hydrogen Storage in Salt Caverns – An Approach to Risk Identification

Understanding the risks of bulk hydrogen storage prior to the global adoption of hydrogen technologies is crucial. This paper focuses on a review of large-scale hydrogen storage with an emphasis on underground salt caverns.

Underground salt caverns may offer a good option for bulk storage of high-pressure hydrogen. There are currently only 4 salt caverns storing hydrogen, but the global capacity for salt cavern hydrogen storage is far greater. In order to foster an industry-wide acceptance of salt caverns and other hydrogen storage methods, there needs to be a review of hydrogen’s potential storage hazards and how to evaluate and manage the potential risks.

Risk assessment begins with hazard identification, followed by understanding potential consequences and evaluating potential risk level. In this paper, hydrogen salt cavern storage practices will be presented to highlight it’s unique risk profile. For example:

• Hydrogen leakage exacerbation
• Conversion of hydrogen into H₂S due to subsurface reactions

This paper proposes a risk assessment framework for a salt cavern hydrogen storage facility, focusing on identifying the consequences and risks posed by hydrogen leaks and subsurface interactions and reactions. Evaluating hydrogen salt cavern storage using standard approaches will provide a means to enable consistent identification and evaluation of hazards, consequences, and risks of hydrogen salt caverns.