Caverns as hydrogen storage: Uniper receives funding notice for project in Lower Saxony

(Düsseldorf / Krummhörn) – The Düsseldorf energy company Uniper SE wants to test the storage of hydrogen in the salt caverns in Krummhörn in northern Germany, northwest of Emden, which have no longer been used commercially since 2017. The company announced the project a few weeks ago.

Lower Saxony's Environment Minister Olaf Lies has now handed over the funding notice amounting to 2,37 million euros for the planned pilot project. Lies said he was pleased that Uniper wanted to rely on cavern storage in Lower Saxony. The path is supported and, due to the current situation, it is “in all of our interests that we follow it quickly”. Uniper estimates the total investment volume at ten million euros.

Volume with 250.000 cubic meters

The storage facilities are designed for natural gas and must be converted for hydrogen. According to the plans, the pilot cavern will be constructed using an existing well. After completion, the storage volume will be up to 250.000 cubic meters. Commissioning is scheduled for 2024. During the trial operation, equipment and materials will be examined for hydrogen compatibility and experience will be gained in storing only green hydrogen in a salt cavern and its delivery and further use.

According to the information, Krummhörn offers ideal conditions due to its geographical location near the windy North Sea and the energy connection to the gas and electricity grid that has existed for decades. The proximity to Wilhelmshaven enables the connection to the Uniper “Green Wilhelmshaven” project. The company is planning an import terminal for ammonia there, as well as a large-scale electrolysis facility for the production of green hydrogen with an output of up to 1.000 megawatts.

Within the Uniper Group, all expertise in underground gas storage is bundled across Europe in Uniper Energy Storage GmbH. The company subsidiary operates natural gas storage facilities in Germany, Austria and Great Britain with a working gas capacity of over 7,5 billion cubic meters

Cavern storage also in Sweden

Announcements of pilot projects for storing hydrogen in caverns also come from Sweden. A “Hybrid“The experimental facility for storing hydrogen in rock caverns was inaugurated. Their capacity is initially 100 cubic meters.

The aim is to “test and understand how hydrogen storage works on a large scale,” says Klara Helstad, head of the sustainable industry department at the Swedish Energy Agency, which is financially supporting the project.

Projects in Germany

In Germany there are a number of plans to store hydrogen in caverns. In addition to the Uniper project, three others have recently been announced.

In the medium term, RWE is planning to test a cavern storage facility in Gronau-Epe, Westphalia. The project is part of the GET H2 joint project, which was initiated by a consortium of industry and research. In the first step, the companies will connect their green hydrogen production facility in Lower Saxony with industrial customers in North Rhine-Westphalia. A pipeline network of around 130 kilometers is planned Lingen in Emsland to Gelsenkirchen. The cavern storage facility is scheduled to go into operation in 2026.
The gas trader VNG wants to put a 2026 meter high research cavern into operation in the Saale district (Saxony-Anhalt) in 180. In the newly built “Energy Park Bad Lauchstadt“The companies and scientists settling there are investigating the production, storage, transport and economic use of green hydrogen under real conditions on an industrial scale.
The Oldenburg energy supplier EWE AG has... Rudersdorf Near Berlin, 160 steel pipes were driven and cemented to a depth of 1.000 meters. EWE wants to “test the safe storage of 500 percent hydrogen” in a salt dome in a 100 cubic meter cavern. The evaluation of the first results is planned for this year.

According to the North Rhine-Westphalia Energy and Climate Agency (NRW.Energy4Climate), the Federal Republic has “via the largest national cavern storage volume in Europe”. The energy storage potential for hydrogen in salt caverns on land and under sea is estimated at 36.000 terawatt hours (TWh). Europe as a whole has a potential of 85.000 TWh. This means that more than 40 percent of possible deposits are located in this country.

There is a lack of storage capacity across Europe

According to the energy agency, there are “ideal conditions for establishing a hydrogen economy” in Europe and especially in Germany. However, there will probably be a lack of 2050 TWh of storage capacity across Europe by 200.

“As of now, the only large-scale storage option for hydrogen is salt caverns,” which could either be converted or created, the agency said. According to the Federal Geothermal Association, these cavities, artificially created by drilling and extracting salt domes, have diameters of up to 100 meters, heights of between 50 and 500 meters and are sometimes hundreds of meters below the earth's surface; in Germany sometimes at depths of up to 2.500 meters.

Storage tanks need cushion gas

The gas content of each storage tank is basically divided into cushion gas and working gas. In caverns, the cushion gas is “necessary to ensure stability”. The proportion is around 30 to 50 percent of the maximum storage volume and remains permanently in the memory. According to the Federal Geothermal Association, this is necessary to enable the minimum necessary storage pressure for optimal injection and withdrawal.

Working gas is defined as the volume of gas that can be stored or removed at any time in addition to the cushion gas. According to the North Rhine-Westphalia Energy Agency, one of the largest cavern storage facilities in Europe is located in Epe in Münsterland. Up to four billion cubic meters of working gas could potentially be stored in a total of 80 caverns.

Conversion from natural gas to hydrogen

Converting natural gas cavern storage to hydrogen is completely possible. This will take around four to four and a half years if the cavern already has a suitable base. If it still needs to be charged, it will take around five years, according to the energy agency.

A completely new building, on the other hand, takes ten to fifteen years to build. A lower energy density and a different compression behavior of gaseous hydrogen means that only 20 percent of the energy content of natural gas is stored with the same storage volume. The maximum potential if all existing caverns in Germany are converted is therefore 33 TWh.

In addition, in salt caverns there is a reduction in the void space of around one percent per year due to movements of the mineral. “In the case of very frequent loading and unloading with hydrogen, this value may possibly be higher.”

Hydrogen demand by 2050 is 800 TWh

In a commissioned by the National Hydrogen Council meta study
The three Fraunhofer Institutes ISI, ISE and IEG analyzed the potential demand for hydrogen and hydrogen derivatives up to 2050. Accordingly, today's hydrogen production in Germany is 57 terawatt hours per year. This amount is almost entirely produced using fossil fuels.

From 2030, the study shows the first relevant demand volumes for green hydrogen and derivatives of up to 80 TWh. This demand will grow to 2040 to 100 TWh in 300. For the year 2050, the range of demand for hydrogen and hydrogen-based synthesis products will increase to 400 to almost 800 TWh. Overall, the maximum demand for hydrogen and its derivatives will increase tenfold between 2030 and 2050.

Photos
Handover of the funding decision (from left to right): Lower Saxony's Environment Minister Olaf Lies, Frank Holschumacher (authorized signatory/Vice President Operational Performance Uniper Storage) and Johann Westerbuhr (Head of Asset Group North). © Uniper SE / Andreas Burmann