EWE has reached an important milestone in the conversion of an existing natural gas cavern into a hydrogen storage facility at the Huntorf gas storage site in the Wesermarsch region: The well, which has been technically adapted for this purpose, has passed the leak test, first with nitrogen and then with hydrogen. This has created an essential prerequisite for future hydrogen storage. From 2028, around 16 million standard cubic metres of hydrogen will be able to be stored there. In this way, the storage facility is intended to make the supply of industrial customers in particular more reliable.
"With the successful leak detection, we have reached another important milestone. In Huntorf, we are showing how existing energy infrastructure can be further developed for the climate-neutral energy supply of tomorrow," says Peter Schmidt, Managing Director of EWE GASSPEICHER GmbH. "Hydrogen storage systems create an important buffer between production and consumption. They provide hydrogen as needed and thus strengthen security of supply."
Hydrogen test confirms secure sealing to the rock
When retrofitting the existing natural gas cavern, the tightness of the borehole is of particular importance. This is because the particularly small hydrogen molecules place high demands on the sealing to the surrounding rock. To this end, the existing borehole was upgraded with a new, cemented pipe tour for hydrogen storage. Among other things, an advanced cement and an additional sealing element were used.
"We first checked the tightness with nitrogen and then successfully confirmed it with hydrogen. All determined values are within the specified test criteria. We were also unable to detect any conspicuous pressure changes in the monitored areas," explains project manager Hayo Seeba. "We have thus proven that the sealing of the cavern borehole to the surrounding rock meets the requirements for hydrogen storage. This is an important basis for further work."
EWE can draw on findings from the HyCAVmobil pilot project, which was successfully completed at the end of 2024. Together with the German Aerospace Center (DLR), the company had built a 500 cubic metre test cavern at the Rüdersdorf gas storage site near Berlin. In several operating cycles, it was possible to prove that hydrogen can be safely stored underground and withdrawn again. The findings from the five-year project are now being incorporated into the large-scale storage facility conversion in Huntorf.
Construction work at the storage site is progressing
With the successful leak test, a significant part of the underground preparations has been completed. Further work on the borehole is planned from mid-November. The pipe system for the subsequent injection and withdrawal of hydrogen as well as additional safety technology will be installed.
At the same time, the work on the surface is progressing. Foundations, cable trays and drainage systems are being built on the storage site. The building construction for the future operating buildings also begins. This will be followed by the installation of further plant technology.
The key technical components include two hydrogen compressors, which EWE has commissioned NEUMAN & ESSER to supply. They play an important role in the subsequent injection and withdrawal of hydrogen. For hydrogen processing, EWE has commissioned industrial service provider Bilfinger with the engineering, installation and commissioning of a drying plant. This removes moisture from the hydrogen taken from the cavern before it is fed back into the grid. Bilfinger's H2Dry technology is to be used on a commercial scale for the first time.
Storage and hydrogen network are growing together
Parallel to the storage facility conversion, the EWE Group companies GTG Nord and EWE NETZ are pushing ahead with the expansion of the hydrogen core network. Work is also currently underway on the future hydrogen pipeline connection for the storage facility in Huntorf. Construction work is already taking place on the storage site and along the planned pipeline connection.
The connection to the storage facility is part of the H₂Coastlink 2 pipeline project. The connection between Huntorf and Sandkrug extends over around 34 kilometres and includes the conversion of around 28 kilometres of existing natural gas pipelines and the construction of a new six kilometres of hydrogen pipeline. The pipeline is to be operational and connected to the hydrogen storage facility by the end of 2027.
With H₂Coastlink 1, a new hydrogen pipeline around 24 kilometres long is also being built between Emden and Leer. In the future, it will transport the hydrogen produced by EWE in Emden into the supra-regional hydrogen network. Such connections are crucial for hydrogen to be able to travel from the generation plants to storage facilities and on to industrial customers.
Hydrogen ramp-up needs reliable framework conditions
The storage facility conversion in Huntorf is part of EWE's large-scale "Clean Hydrogen Coastline" project. This also includes the 320-megawatt hydrogen production plant currently under construction in Emden. Together with the new and converted pipeline infrastructure and the future storage facility in Huntorf, an integrated hydrogen infrastructure is gradually being created in northwestern Germany. The project is funded by the federal government and the state of Lower Saxony as part of the European IPCEI programme (Important Project of Common European Interest)
For EWE, Huntorf is a first step on the way to a comprehensive hydrogen storage infrastructure.
"We are investing today in infrastructure that will be needed for the hydrogen ramp-up of tomorrow. The support from the federal government and the state of Lower Saxony is an important signal in this regard," emphasises EWE GASSPEICHER Managing Director Peter Schmidt. "However, to ensure that we do not remain with individual pioneering projects in the long term, we need reliable regulatory and economic framework conditions. Investments in further hydrogen storage facilities must be economically viable and plannable. At the same time, generation, grid expansion, storage and demand must go hand in hand. This is the only way to develop an efficient hydrogen economy."
Facts and figures at a glance
- Location: Huntorf, Wesermarsch district, Lower Saxony
- Operator: EWE GASSPEICHER GmbH
- Project: Conversion of one of seven existing natural gas caverns
- Working gas volume: around 16 million standard cubic meters of hydrogen
- Converted storage quantity: around 1,440 tonnes of hydrogen
- Injection/withdrawal capacity: A total of 35,000 standard cubic meters per hour
- Current milestone: Successful leakage verification of the existing well, which has been upgraded for hydrogen, with nitrogen and hydrogen
- Planned commissioning: 2028
- Planned connection to the hydrogen core network: 2028
- Overall project: Clean Hydrogen Coastline
- Funding: European IPCEI programme, supported by the federal government and the state of Lower Saxony
