Hydrogen salt cavern storage (H2SaltCavern)

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Challenge

Storing hydrogen in salt caverns can play an important role in helping deliver the energy transition while meeting the targets of the Paris Agreement. Hydrogen storage at scale will be used for various purposes such as energy security, decarbonizing industrial processes, balancing supply and demand, and maximizing recovery of variable electricity from wind and solar. There are four commercial hydrogen salt caverns and several pilot projects in operation globally. As the energy transition accelerates, the number of caverns storing hydrogen is expected to increase significantly. The underlying question is whether existing standards for natural gas salt cavern storage can be applied to hydrogen from a safety / major hazard perspective and, if not, how they need to be changed.

The storage of hydrogen in salt caverns requires good design, based around safety. DNV has contacted nearly 50 companies and gathered extensive feedback on the top industry challenges. Following studies by the Dutch Ministry of Economic Affairs and Climate (KEM-28) and German Federal Ministry Economic Affairs (DVGW Roadmap for Standardization of Hydrogen) on development areas, DNV has identified the risk of fire & explosion as a key knowledge gap. Therefore DNV proposes to develop guidelines to further industry understanding and approaches to safety for these topics:

1. Subsurface failure consequences
2. Surface failure consequences
3. Risk mitigation methods
4. New and repurposed facilities
5. Pipeline connection failures

Objective

DNV would bring together stakeholders on a 20-month JIP to develop a European focused and rationalized safety approach for development and operation of salt caverns for storage of hydrogen. The JIP would review the applicability of existing natural gas storage guidance for hydrogen with a focus on fire and explosion consequences and risk mitigation methods, covering various well diameters, storage capacities, multiple caverns/wellheads, confinement, congestion, a sensitivity study of uncertainties e.g. immediate vs delayed ignition, overpressure levels and whether numerical models for natural gas need to be adapted to accurately simulate hydrogen.

Approach

The scope would consist of Phase 1 and Phase 1 Extension. Phase 1 would focus on data gathering, assessment of state-of-the-art practices, scenario development, threat assessment, identification of uncertainties and a gap analysis of standards & practices. This would be followed by development of risk mitigation methods for new-build and repurposed facilities, evaluation of the effectiveness of those mitigation measures, ideas for extra requirements for hydrogen storage to cover the gaps and development of a guideline. The Phase 1 Extension (subject to additional funding) would either address analysis and potential testing or address different topics as directed by the steering committee.

Project details

The project would aim to kick-off in May 2025, subject to funding and partners. The project aims to enhance confidence that the risks are understood, help demonstration of adherence to SEVESO III Directive / COMAH regulations, and land use planning, facilitate certification   and give participants the opportunity to influence best practice. Companies are requested to express intent to participate (subject to scope & contract) for receipt of a formal proposal.