The storage operator EWE has completed the first tests of its hydrogen cavern in Rüdersdorf. According to the company, the slow injection and withdrawal were successful. A second test phase with an increased flow rate is already planned.
During the three-month test phase, the technical system "worked well" during injection and withdrawal, according to EWE project manager Hayo Seeba. In the first test scenario, the focus was on slow injection and withdrawal. This was "comparable to the operation of a conventional natural gas storage facility". The EWE engineers analyzed the performance of the system technology as well as the pressures, temperatures and flow rates of the hydrogen.
The purity and quality of the hydrogen after storage was also examined. For future applications, particularly in the mobility sector, this should be as high as possible. A purity of 100 percent would be the optimum. The result: the quality of the hydrogen changed "only slightly" as a result of storage. The gas also absorbed very little moisture from the underground cavity.
In the next test phase, EWE wants to increase the hydrogen flow rate in order to achieve faster storage cycles. The pressure in the hydrogen cavern will rise and fall faster than in the first operating cycle. The second test phase is scheduled to begin at the end of May and will again last three months.
Planning the next test phase
EWE is testing a total of three different injection and withdrawal scenarios with different flow rates. The storage operator is thus simulating the scenarios that can be expected for different storage customers in the future. This is because underground hydrogen storage facilities are subject to different conditions than today's natural gas storage facilities: "They would have to work much more flexibly and quickly," explains project manager Hayo Seeba.
EWE intends to use the findings from Rüdersdorf for a larger storage project in Huntorf in Lower Saxony. This is part of the large-scale connecting project "Clean Hydrogen Coastline". In February, EWE received IPCEI funding approval from the European Commission for this project, and the federal and state governments are currently reviewing the allocation of funding.
With 37 salt caverns in Huntorf, Nüttermoor, Jemgum and Rüdersdorf, the energy group claims to have 15 percent of all German cavern storage facilities that would be suitable for storing hydrogen in the future. The investment volume for the HyCAVmobil storage project amounts to around ten million euros - four million of which will come from EWE's own funds. The Oldenburg-based company and its project partner, the German Aerospace Center (DLR), are receiving the remaining sum from the Federal Ministry of Digital and Transport as part of the National Innovation Programme for Hydrogen and Fuel Cell Technology.
