Austrian energy company RAG is confident its portfolio of European underground gas storage facilities could easily be converted to take hydrogen after trials showed no evidence of significant degradation of steel or cement components.

Embrittlement of steel and deterioration of other key materials, such as cement, are widely cited as potential issues when repurposing natural gas infrastructure to take hydrogen. But RAG’s extensive trials show hydrogen injections and withdrawals from underground reservoirs had no significant impact on the facility’s materials, according to Markus Pichler, a hydrogen storage expert at RAG.

“Ideally, you would just use your old gas storage facility, put hydrogen in there and be done with it. And it seems that it is almost that easy—not fully, but almost as easy,” Pichler told a recent webinar for consultancy Mission Hydrogen.

“We want to use our commercial storage facilities for hydrogen—we have those facilities and they are not very old, they are quite modern and we want to use them with a minimal amount of change.”

“Ideally, you would just use your old gas storage facility, put hydrogen in there and be done with it” Pichler, RAG

RAG is one of Europe’s largest energy storage providers, with a total capacity of 66TWh.

The company’s work with hydrogen has included testing steel in a laboratory up to a 100pc share of hydrogen at pressures of to 100 bars and temperatures of up to 40°C, emulating depleted reservoir conditions.

Results showed “no infringement and no changes whatsoever that would be outside of standard”, Pichler says.

Testing of the cement used to plug wells showed “no or only minor changes”, he adds. Any changes occurring in the cement were confined to a type of calcination that does not alter the material’s performance.

RAG’s trials, which involved the injection of more than 100,000m³ of hydrogen for a storage period of three months, also showed it is possible to withdraw over 80pc of the hydrogen originally injected into a depleted gas reservoir, Pichler says.

RAG is also developing technology to create biomethane in its storage facilities by reacting hydrogen and CO₂ with microbes, a process it wants to demonstrate on an industrial scale.

Seasonal storage

Europe’s energy crisis in the wake of Russia’s invasion of Ukraine has highlighted the importance of seasonal natural gas storage in the region’s energy system. It also shows the importance of developing flexible hydrogen storage as the continent’s demand for the energy carrier grows in the coming decades, with supply dictated by seasonal variations in renewable generation and by the availability of imports.

Industry group Gas Infrastructure Europe estimates Europe will need around 70TWh of hydrogen storage capacity by 2030, growing to around 450TWh in 2050 as the region raises both local production and imports.

Hydrogen storage in salt caverns is “low-hanging fruit”, but storage in porous structures such as depleted gas fields and aquifers will also be needed, the industry group says.

“To be ready for substantial hydrogen demand and regional pipeline networks by 2030, we need to start on the storage now. Storage system operators have a key role—their experience will be needed,” it says.

70TWh – Estimated European storage capacity needed by 2030

In addition to RAG’s work with hydrogen, several other storage projects are in progress. Dutch gas network operator Gasunie is developing four salt caverns at Zuidwending in the north of the Netherlands.  Spatial planning and permitting for the caverns and related above-ground installations started this summer, and FID is expected next year.

“To prepare for the investment decision next year, investigation of client interest for hydrogen storage services is already well on its way and will have permanent attention throughout the whole development,” Gasunie tells Hydrogen Economist.

“Demonstration projects like this are a stepping stone towards full-scale hydrogen storage facilities in 2030 that are crucial in the integrated hydrogen ecosystem.”

Elsewhere, German energy company Uniper is developing a new salt cavern specifically built for hydrogen at its Krummhoern natural gas storage site in northern Germany. The €10mn ($10.2mn) project is scheduled to start operating by 2024 with a capacity of up to 250,000m³.

In the UK, energy company Centrica is in talks with the government over a £2bn ($2.4bn) proposal to restart the Rough offshore gas storage facility this winter and ultimately convert it into one of the world’s largest hydrogen storage sites, CEO Chris O’Shea said in a recent earnings presentation.

Rough, a depleted gas field off England’s northeastern coast that has been closed since 2017, has the potential to be a key enabler of the UK’s planned expansion of low-carbon hydrogen production capacity to 10GW by 2030, he says.

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Author: Stuart Penson