Underground hydrogen storage. Final report. [Salt caverns, excavated caverns, aquifers and depleted fields]

TLDR: In this paper, the authors evaluated the technical and economic feasibility of storing hydrogen in underground storage reservoirs and concluded that it is now both safe and economic to store hydrogen in such underground reservoirs.

Abstract: The technical and economic feasibility of storing hydrogen in underground storage reservoirs is evaluated. The past and present technology of storing gases, primarily natural gas is reviewed. Four types of reservoirs are examined: salt caverns, excavated caverns, aquifers, and depleted fields. A technical investigation of hydrogen properties reveals that only hydrogen embrittlement places a limit on the underground storage by hydrogen. This constraint will limit reservoir pressures to 1200 psi or less. A model was developed to determine economic feasibility. After making reasonable assumptions that a utility might make in determining whether to proceed with a new storage operation, the model was tested and verified on natural gas storage. A parameteric analysis was made on some of the input parameters of the model to determine the sensitivity of the cost of service to them. Once the model was verified it was used to compute the cost of service of storing hydrogen in the four reservoir types. The costs of service for hydrogen storage ranged from 26 to 150% of the cost of the gas stored. The study concludes that it is now both safe and economic to store hydrogen in underground reservoirs.