Hydrogen filling with 90 tonnes at pilot project H2CAST Etzel successfully completed

• Further milestone in the conversion of existing caverns for hydrogen use at Etzel achieved as planned.
• Approximately 90 tonnes, or 1 million standard cubic metres of hydrogen, have been safely injected by STORAG ETZEL and project partner Gasunie into the caverns.
• The unique pilot test plant to test efficiency of hydrogen purification processes and multi-cyclic cavern operation is under-construction and will be ready for the first tests in 2026.
• The H2CAST consortium aims to demonstrate the feasibility of underground hydrogen storage.

“Following the conversion of the caverns and continuous monitoring of tightness and integrity, another important milestone has been achieved in line with the high safety standards customary at the Etzel site,” said Carsten Reekers, Project Manager H2CAST Etzel at STORAG ETZEL.

Particular attention is now focused on the completion of the above‑ground facilities for gas purification, compression and gas quality monitoring, which are being newly constructed for hydrogen. Various gas purification methods and their efficiency will be tested. Preparations for this are already well advanced.

“Gasunie is confident that together with our employees and partners we will master this next step as a team. Being able to rely on the skilled expertise within the H2CAST partners we believe that this project will guide and strengthen the hydrogen path.”, states Eddy Kuperus, Business Development Manager Hydrogen Storage at Gasunie.

H2CAST Etzel: valuable experience gained since 2022

Carsten Reekers: “The knowledge that we gain from the H2CAST pilot project will contribute to the future underground hydrogen storage. In recent years since early 2022, valuable experience has already been gained. This supports the statement that there is a high degree of comparability with natural gas storage and that the existing caverns at Etzel are suitable for hydrogen storage.”

Challenges in hydrogen procurement

The injection forms part of the research and development project ‘H2CAST Etzel’, which develops the technical implementation of hydrogen storage in salt caverns. “The filling of the test cavern with hydrogen and the associated procurement process for the H2CAST Etzel research project highlighted the early stage of development of the German market. At the start of filling in 2023, high‑pressure trailers and filling stations (>200 bar) were only available to a very limited extent. Combined with the lack of local production – with some deliveries over distances of up to 1,000 km – this resulted in a high proportion of hydrogen costs.”

“Meanwhile, the market has evolved, allowing us to secure a delivery from a nearby hydrogen producer during the project period—significantly lowering both logistics and production costs. Looking ahead, once Etzel is connected to the approved national hydrogen ‘core network’, the site will become a key hub for hydrogen storage within the future energy system,” said Project Manager Reekers.

“Our gas operations specialists have the hydrogen filling process steps safely under control. Handling of the new energy carrier is carried out professionally and routinely on a day‑to‑day basis,” Reekers continued.