National Gas and Gravitricity have secured £500,000 from Ofgem to develop a new type of underground hydrogen storage.
The H2FlexiStore system, designed by Edinburgh-based energy storage firm Gravitricity, aims to store up to 100 tonnes of green hydrogen in lined geological shafts.
The technology, which could see a demonstrator built in 2026, is intended to offer a flexible, resilient solution to future hydrogen network needs.
“This project is a critical step forward in ensuring the UK’s gas networks are ready for a hydrogen-powered future,” said Kelvin Shillinglaw, Innovation Analyst at National Gas.
“By embedding resilience with operational hydrogen storage directly into the transmission system, we can maintain operational flexibility, reduce costs for consumers, and support the decarbonisation of heat and power.”
Unlike salt caverns, which are only available in limited locations, H2FlexiStore can be sited more widely. This flexibility could help solve one of the biggest challenges facing green hydrogen: storing large quantities close to where it is needed most.
“Given the strategic need for grid scale energy storage both nationally and internationally, it is crucial that enabling hydrogen storage technologies such as H2FlexiStore are commercially mature in time,” said Martin Wright, Co-Founder and Executive Chairman at Gravitricity. “This support from Ofgem enables us to prepare both technically and commercially for the delivery of a demonstration project next year.”
The consortium, which also includes Southern Gas Networks, Guidehouse, Edinburgh University, Energy Reform and Premtech, will now model and design the system.
If successful, the final project phase could attract multi-million-pound backing from Ofgem’s Strategic Innovation Fund.
Gravitricity estimates each shaft could hold 3.3GWh of energy—equivalent to 10 million miles in a hydrogen car—offering a future-proofed solution that could support hydrogen export ambitions, particularly in Scotland.
