EWE's Huntorf hydrogen cavern passes leak test ahead of a 2028 start

EWE says a natural gas cavern it is converting to hydrogen storage at Huntorf, in Lower Saxony's Wesermarsch district, has passed its well leak test, first with nitrogen and then with hydrogen. From 2028 the cavern is to hold around 16 million standard cubic metres of hydrogen, which EWE puts at about 1,440 tonnes, with a total injection and withdrawal capacity of 35,000 standard cubic metres per hour, according to the company's November 6, 2026 release. It is one of seven natural gas caverns at the site.

The borehole is where the conversion gets exacting, because hydrogen's very small molecules place high demands on its seal to the surrounding rock. EWE refitted the existing well with a new cemented pipe string, an advanced cement and an additional sealing element. Project manager Hayo Seeba said all values were within the test criteria and that no conspicuous pressure changes turned up in the monitored areas.

Construction continues on both levels. From mid-November, crews are due to install the tubing for injection and withdrawal plus additional safety equipment in the well, while foundations and operating buildings go up on the surface. NEUMAN & ESSER is supplying two hydrogen compressors, and Bilfinger is building a drying plant that EWE says will be the first commercial-scale use of Bilfinger's H2Dry technology. The cavern's pipeline link, H₂Coastlink 2, runs about 34 kilometres from Huntorf to Sandkrug, about 28 of them converted gas pipeline, and is due to be operating and connected by the end of 2027. The storage belongs to EWE's Clean Hydrogen Coastline project, funded by the federal government and Lower Saxony under the EU's IPCEI programme, alongside a 320 MW hydrogen production plant under construction in Emden.

Huntorf has stored something other than natural gas underground before: Uniper's compressed-air storage power plant there, fed by two salt caverns, was commissioned in 1978. EWE calls Huntorf a first step, and Peter Schmidt, managing director of EWE GASSPEICHER, used the milestone to ask about the next ones: "Investments in further hydrogen storage facilities must be economically viable and plannable."