SaltHy: how underground hydrogen storage is supporting the European Hydrogen Backbone

Natural gas storage facility in Harsefeld
Hydrogen is a versatile energy carrier that can be stored using power-to-gas technology. It is therefore a key building block in the energy transition and can help ensure a secure energy supply in the event of short- or longer-term fluctuations.
By Catherine Gras, CEO of Storengy UK & Germany

Storage-specific challenges

Despite all these advantages, there are numerous challenges that need to be overcome when switching from natural gas to hydrogen or expanding existing natural gas storage facilities to store hydrogen. For instance, hydrogen has a lower energy content than natural gas. Consequently, converting only existing salt caverns would significantly reduce storage volumes, leaving Europe with only 4% of its current volume. In order to increase this potential, new storage facilities will therefore need to be built.

As Europe’s largest operator of natural gas storage facilities, Storengy – an ENGIE company – will play its part by constructing several hydrogen storage facilities with the aim of achieving a total hydrogen storage capacity of 1 TWh across France, the United Kingdom, and Germany by 2030. In line with these ambitions, Storengy Deutschland is currently planning to construct its first hydrogen storage facility in Germany, called SaltHy (Storage Alignment with Load and Transport of Hydrogen).

Conversion potential of salt caverns in Europe
Due to hydrogen’s lower energy content compared to natural gas, converting only existing salt caverns would result in a significant reduction in storage volumes, leaving Europe with only 4% of its current volume.

What is SaltHy?

As part of the SaltHy project launched in 2021, the existing natural gas storage facility in Harsefeld will be expanded to store green hydrogen. The storage facility near Hamburg will be constructed in the second part of this decade at a depth of around 1,200–1,500 metres and will initially hold up to 5,000 tonnes of hydrogen. The project will therefore make an important contribution to developing a hydrogen infrastructure in northwest Germany.

Current status of the project

In 2022, Storengy Deutschland verified the site’s geological and technical suitability for storing hydrogen. Hydrogen storage facilities such as SaltHy will play a key role in connecting the energy infrastructure within the European Union. In this context, Storengy Deutschland has submitted the scheme to the EU Commission as a Project of Common Interest (PCI). At the national level, SaltHy is already listed as a storage facility in the National Hydrogen Council’s roadmap.

Connection to relevant transport networks

Storengy plans to connect the new hydrogen storage facility to Gasunie’s regional pipeline network, HyPerLink. This will provide direct access to the Hamburg Green Hydrogen Hub distribution networks and the Danish transport grid. SaltHy is therefore contributing to the safe and efficient development of an import route between Denmark, as a potential exporter of green hydrogen, and German consumption centres, e.g., in industry, shipping and aviation.

Further projects: the HyPSTER demonstrator

Storengy is involved in several hydrogen storage research projects and will gain its first practical experience of storing hydrogen in underground salt caverns as part of the HyPSTER hydrogen storage project in France.

HyPSTER is the first EU-supported project for large-scale green hydrogen underground storage in salt caverns. This year, the demonstration facility, located in Etrez, France, will store around three tons of hydrogen and simulate 100 injection/withdrawal cycles. Photo credit: ArcomDesign

HyPSTER is a salt cavern with a potential capacity of 44 tons of hydrogen. This year, we will store around three tons of hydrogen and simulate 100 injection/withdrawal cycles.

Following the HyPSTER demonstrator, a commercial scheme could be developed over the next three years. Surface installations for compressing and, in particular, purifying hydrogen would then allow the cavern to be used to its full storage capacity by 2026.

HyPSTER’s role will be to help develop the use of low-carbon or renewable hydrogen in the Auvergne-Rhône-Alpes region in France by ensuring security of supply and providing flexible solutions for manufacturers and hydrogen refuelling station operators. As a commercial pilot project, it will provide initial technical, operational, and commercial feedback that will be useful for the subsequent large-scale deployment of hydrogen storage.

About Storengy Deutschland

Storengy Deutschland, an ENGIE Group company, is one of the leading gas storage companies in Germany. With around 150 employees across Germany, we are a reliable partner for storage services: we plan, build, and operate storage facilities and market their storage capacities. Our mission is to produce and store climate-neutral energy in order to sustainably supply tomorrow’s generations. We are therefore developing innovative solutions for storing hydrogen and producing renewable gases. The company’s headquarters are located in Berlin.

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About this Featured Article

This article was selected and posted by the HTW Editorial Team. It was originally pubished in the Hydrogen Tech World magazine – an open-access, bimonthly digital publication dedicated to technologies associated with hydrogen production via water electrolysis, hydrogen transport, storage and distribution, and hydrogen application in fuel cells.

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Matjaž Matošec
Matjaž Matošec
Matjaž is a seasoned writer and communicator eager to effectively disseminate knowledge and always on the lookout for exciting stories and people willing to share their insights and first-hand experience. He is curious about all things industrial and passionate about the energy transition. He is editor-in-chief of the Hydrogen Tech World magazine, manager of the Hydrogen Tech World Conference, and research manager at Resolute Research.

All images were taken before the COVID-19 pandemic, or in compliance with social distancing.