National Gas looks to underground hydrogen storage

The system, known as H₂FlexiStore, has been developed by Edinburgh energy storage specialists Gravitricity, and is designed to hold up to 100 t of green hydrogen in purpose-built underground lined shafts.

The technology can be located where required – for example as part of the National Gas network or next to large industrial users.

The Ofgem funding will enable a consortium – which also includes Southern Gas Networks, Guidehouse, Edinburgh University, Energy Reform and Premtech – to design and model a working system over the next six months, ahead of a potential demonstration phase next year.

The funding comes from Ofgem’s Strategic Innovation Fund and follows the successful completion of a National Gas led feasibility study in 2024, which identified H₂FlexiStore as the preferred technology to provide locationally flexible hydrogen storage.

The initial study concluded that underground nodal storage would compensate for the loss of ‘linepack’ (the amount of energy that can be stored in a pipe network) when transitioning to green hydrogen as a fuel. In other words, strategically located nodal storage can improve the resilience and operational efficiency of a hydrogen gas network, with a view to ensuring security of supply to customers.

Once the design project is successfully completed, a third and final project phase could be secured, which would see the delivery of a technical demonstration project, supported by multi-million-pound funding from the Strategic Innovation Fund.

A successful demonstrator project would validate the benefits of underground storage to the hydrogen industry and key infrastructure projects such as Project Union, which is investigating the potential to repurpose the existing gas grid for hydrogen to create a UK hydrogen backbone to connect production and storage assets to demand.

Gravitricity’s Co-Founder and Executive Chairman, Martin Wright, says:“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 to offer cost effective resilience within current and future energy systems.

“This support from Ofgem, enables us to prepare both technically and commercially for the delivery of a demonstration project next year and the early commercial projects within our existing pipeline of opportunities.”

Kelvin Shillinglaw, Innovation Analyst at National Gas, says: "This project is a critical step forward in ensuring the UK’s gas networks are ready for a hydrogen-powered future.

“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."

Gravitricity’s patented system uses purpose built lined geological shafts to store up to 100 t of pressurised hydrogen at 200 bar per shaft, equivalent to 3.3 GWh of raw energy (enough to drive 10 000 000 miles in a hydrogen fuel cell car).

The company states their technology can be sited in a wide range of geological conditions, thereby fitting an unfulfilled niche in the UK’s green hydrogen plan – the need to safely and securely store large amounts of hydrogen close to demand.

Although the UK does have a limited number of underground salt caverns suitable for hydrogen storage, they only exist in very specific locations, which don’t always match up with where current or future storage demands will be situated.

Martin Wright concludes: “By deploying H₂FlexiStore, we anticipate network operators will be able to extend the life of existing assets as they transition to hydrogen by managing linepack swings more smoothly. In doing so, our technology improves the resilience of the network and overall energy security.

“This is of particular importance for a number of regions in the UK and particularly across Scotland, where there are no alternative or existing geological storage solutions.”

Wright adds that in addition to its clear application in the UK, Gravitricity’s underground storage technology is likely to be deployed more widely in export markets as other countries seek to deploy their own hydrogen solutions.

The Scottish Hydrogen Assessment’s ‘Green Export Scenario’ stated that Scotland could produce 3.3 million t of green hydrogen annually by 2045, with 2.5 million t designated for export, and initial deliveries to mainland Europe expected before 2030. Gravitricity has separately completed commercial and technical feasibility work to confirm that H₂FlexiStore can be deployed in this role.

 

Read the article online at: https://www.tanksterminals.com/storage-tanks/11062025/national-gas-looks-to-underground-hydrogen-storage/