EWE Successfully Tests Hydrogen Storage in Rüdersdorf

The energy service provider EWE has completed its research project HyCAVmobil at its gas storage site in Rüdersdorf near Berlin. Within the scope of the hydrogen storage project, EWE and its partner, the German Aerospace Center (DLR), demonstrated the feasibility of safely storing hydrogen in an underground cavern. Moreover, the research showed that the hydrogen's purity level changes only minimally when stored in a newly constructed cavern like the one in Rüdersdorf. This is especially significant for applications in mobility.

Insights for Large-Scale Storage Applicability

The insights gained by EWE from constructing and operating the 500-cubic-meter test cavern are now being applied to caverns with 1,000 times the volume. "Our goal is to establish large-scale caverns for hydrogen storage. EWE alone possesses 37 salt caverns, accounting for 15% of all German cavern storage sites suitable for hydrogen storage," said EWE CEO Stefan Dohler at the closing press conference in Rüdersdorf. With this capability, green hydrogen produced from renewable energy can be stored in large quantities, made available on demand, and become a key component for achieving climate targets. "Proving the safe storage of hydrogen is a major step towards climate protection and securing renewable energy supply. Hydrogen allows energy from the sun and wind to be stored in large volumes, especially for industrial use," Dohler emphasized.

Milestones and Challenges in HyCAVmobil

Since the start of HyCAVmobil in 2019, EWE has achieved several project milestones, though challenges arose, requiring adjustments to planned steps. "This is not unusual in research projects. After various technical modifications, we were especially relieved to reach the first and most critical milestone before the actual construction of the cavern, which is the size of a single-family house. This milestone involved proving that the cavern borehole, extending 1,000 meters deep, was sealed," said Ralf Riekenberg from EWE's hydrogen team in Rüdersdorf. Challenges included unexpected, hydrogen-specific issues with the cementation between the rock and the steel casing. EWE resolved these through multiple sealing tests.

After injecting hydrogen into the test cavern and starting the facility's operation, EWE gained experience with hydrogen injection and withdrawal at various pressures. DLR researchers conducted extensive gas composition analyses. A new laboratory was established in Oldenburg for the HyCAVmobil project to analyze hydrogen quality and purity, including samples from the Rüdersdorf cavern. This quality is especially critical for fuel cells used in vehicles to convert hydrogen into electricity.

"Based on our investigations, we can confirm that the cavern, in this configuration, is suitable for large-scale hydrogen storage. The hydrogen's quality upon withdrawal remains high enough that only minimal purification is needed for further use," noted Dr. Alexander Dyck, Department Head of Urban and Building Technologies at DLR's Institute of Networked Energy Systems.

Expanding to Large-Scale Projects

EWE plans to apply these insights to a large-scale project at its Huntorf site in the Wesermarsch region. There, a natural gas cavern is being converted for hydrogen storage. "However, we need to assess the purity of hydrogen stored in this existing cavern separately, as it previously stored natural gas that cannot be fully removed," Riekenberg explained. This Huntorf project is part of the larger "Clean Hydrogen Coastline" initiative, integrating hydrogen production, storage, transport, and use, particularly in industry. Supported under the European IPCEI program, EWE received funding approval this summer from Federal Minister of Economics Robert Habeck.

Urgent Need for Political Framework

To repurpose existing natural gas storage or build new hydrogen storage facilities, regulatory clarity and financial frameworks are urgently needed due to the long lead times. "No one can invest in hydrogen storage entirely competitively from scratch to support market ramp-up," said Dohler. "Just as initial support is needed for the hydrogen core network, the same applies to the storage sector. A coordinated development of the hydrogen core network and storage is essential for system stability and supply security."

Rüdersdorf: A Key Component for the Hydrogen Network

EWE’s Rüdersdorf site is geographically well-positioned near the Berlin metropolitan region and hydrogen pipelines. The company has signed an agreement with ONTRAS Gastransport to integrate the site into Germany's planned hydrogen core network. EWE has also joined the "Flow – Making Hydrogen Happen" initiative with gas transmission operators GASCADE, ONTRAS, and terranets bw to build a transport infrastructure connecting northeastern and southwestern Germany.

€14 Million Investment in a Climate-Friendly Future

The total investment in HyCAVmobil reached €14 million over five years, with EWE contributing approximately €8 million of its own funds. The remaining €6.5 million was provided as part of Germany's National Hydrogen and Fuel Cell Technology Innovation Program, funded by the Federal Ministry for Digital and Transport and coordinated by NOW GmbH.

EWE remains committed to advancing hydrogen storage technologies and integrating its facilities into Germany's hydrogen infrastructure, pending the establishment of a supportive political framework.