In Lower Saxony, Storag Etzel GmbH has launched a pilot project for underground hydrogen storage. In H2CAST, the North German company is testing the storage of around 90 tons of hydrogen under real-world conditions. The hydrogen storage facility is to be supplied via pipeline after completion of the core network.
Storag Etzel has begun storing hydrogen in two converted salt caverns in Friedeburg-Etzel. The company aims to store a total of 90 tons of hydrogen as part of the H2CAST research project. The first quantities were already stored during the 2024/25 turn of the year. In 2024, the conversion and leak tests under maximum gas pressure on the two caverns were completed. These tests formed the basis for the now-started large-scale storage.
"After expected initial difficulties in procuring hydrogen – it's clear that the hydrogen market is still in its infancy – several tons are now safely stored underground at a maximum pressure of 170 bar, as of late January," says Carsten Reekers, project manager of the H2CAST Etzel research and development project. "We are proud of what we have achieved so far and have now shown that the existing facilities in the Etzel cavern field are suitable for hydrogen storage."
Transport and Network Connection
Hydrogen supply currently occurs exclusively by truck. By summer 2025, up to three truck loads are expected to arrive in Etzel weekly. Completely filling the cavern roof requires approximately 200 trailer loads at a pressure of 300 bar. After completion of the hydrogen core network, the facility is to be connected to a pipeline.
Gas storage occurs via a specially equipped cavern head. The hydrogen displaces brine from the caverns, which is transported away via the brine system. The maximum storage pressure in the caverns is 170 bar. According to Storag Etzel, the caverns in Etzel offer the possibility of flexible scaling. Existing gas and oil storage facilities can be converted for hydrogen use. The State Office for Mining, Energy and Geology has already approved hydrogen storage.
The North German company plans to build and commission hydrogen purification facilities in 2025. Different procedures and their efficiency are to be tested. Preparations are already running intensively, according to the press release published on January 21.