Huntorf: Converted natural gas cavern passes hydrogen leak test

EWE operates seven natural gas caverns at its Huntorf site, one of which is currently being converted into a hydrogen store. The latest test checked whether the cavern borehole is tightly sealed against the surrounding rock. This is particularly demanding with hydrogen, as its molecules are very small. The existing borehole was therefore fitted with a new, cemented casing string for future use. Among other things, an improved cement and an additional sealing element were used.

First nitrogen, then hydrogen

The test was carried out in two stages: first with nitrogen, then with hydrogen. According to project manager Hayo Seeba, all measured values were within the specified test criteria, and no noticeable pressure changes were recorded in the monitored areas. The seal therefore meets the requirements for hydrogen storage. Peter Schmidt, Managing Director of EWE GASSPEICHER GmbH, sees the result as proof that existing energy infrastructure can be developed further for the future. Hydrogen storage facilities balance fluctuations between production and consumption, thereby strengthening security of supply.

Storage as a building block of regional hydrogen infrastructure

The facility is to have a working gas volume of around 16 million standard cubic metres, equivalent to roughly 1,440 tonnes of hydrogen. Total injection and withdrawal capacity is 35,000 standard cubic metres per hour. Industrial customers in particular, who rely on a dependable supply, are expected to benefit. The store will be connected via the H₂Coastlink 2 pipeline project, a link of around 34 kilometres between Huntorf and Sandkrug. About 28 kilometres consist of repurposed natural gas pipelines, while around six kilometres are being newly built. The pipeline is scheduled to be operational by the end of 2027, with connection to the German hydrogen core network planned for 2028.

The project is part of EWE's "Clean Hydrogen Coastline" initiative, which also includes the 320-megawatt electrolysis plant currently under construction in Emden. It is funded under the European IPCEI programme with support from the German federal government and the state of Lower Saxony. Huntorf also builds on findings from the HyCAVmobil research project, in which EWE and the German Aerospace Center (DLR) operated a 500-cubic-metre test cavern in Rüdersdorf near Berlin until the end of 2024.

Next steps towards commissioning in 2028

Work on the borehole will continue from mid-November, when the piping system for injection and withdrawal and additional safety equipment will be installed. Above ground, work on foundations, cable routes, drainage and operating buildings is running in parallel. Two hydrogen compressors and a plant for drying the withdrawn hydrogen have already been commissioned. According to Schmidt, the ramp-up requires reliable regulatory and economic framework conditions. Only then can investments in further storage facilities be planned, so that the market does not stop at individual pioneering projects.