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H2CAST Etzel

Making energy transition work.

About the project

The H2CAST Etzel project is intended to demonstrate the feasibility of large-volume underground storage of hydrogen and to prove the suitability of the salt caverns in Etzel for hydrogen storage. Operational hydrogen storage operations will be tested and serve to build a hydrogen service industry. H2CAST stands for H2 CAvern Storage Transition, i.e. the conversion of existing caverns and facilities in Etzel for the future necessary storage of hydrogen as a building block for a future energy system.

More on the project


Wellhead technology for hydrogen caverns

Wellhead technology for hydrogen caverns

With the start of the North German pilot project "H2Cast Etzel", an optimal design of the hydrogen-compatible wellheads will be developed with the project partner Hartmann Valves.

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STORAG ETZEL as part of the "ENERGY-HUB PORT OF WILHELMSHAVEN" was an active participant of the kick-off event on "National Topics of the "Energiewende" in Berlin

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Group picture after handing over the funding decisions in EtzelFirst section of H2CAST Etzel launched

First section of H2CAST Etzel launched

The first phase of the H2 pilot project "H2CAST Etzel" starts - the R&D project will initially run until the end of 2024.

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Wilhelmshaven hydrogen capital

Wilhelmshaven hydrogen capital

Joint initiative of 14 companies drives development of Wilhelmshaven into hydrogen capital. DENA study to show ways to become an H2 hub.

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Project Partners

STORAG ETZEL GmbH are the biggest independent provider of cavern storage capacity in Germany. We are proud to make our contribution to the safety of energy supply and gas grid stability in Germany and Northwestern Europe. At Etzel, East Frisia, we are constructing, operating and leasing caverns for the purpose of bulk storage of crude oil and natural gas since 1971. The cavern site Etzel is situated on the North German energy hub near Wilhelmshaven, with a connection to the deep water port.

Our customers are well known energy trading companies as well as Europeans stockpiling organizations. A major part of the German oil stockpiling obligation is stored in our caverns here at Etzel. Beyond the currently existing 75 caverns, further storage cavities within the Etzel salt dome can be created in total. There is an expansion potential up to 99 cavern locations.


DEEP.KBB GmbH, based in Bad Zwischenahn and Hannover, is one of the leading service companies in the field of liquid and gaseous hydrocarbon storage in the geological subsurface in Europe. DEEP.KBB has over 50 years of international experience in the field of underground storage. DEEP.KBB is significantly involved in the design, construction and operation of underground storage facilities in salt rock for the storage of natural gas, mineral oil, gas and oil products, as well as storage of renewable energy, especially compressed air and hydrogen. The main focus of DEEP.KBB's services in the underground sector is on the disciplines of geology, rock mechanics, drilling and completion technology, thermodynamics, solution mining, mechanical integrity tests, cavern flooding, gas filling and reservoir engineering.


The Institute of Networked Energy Systems was incorporated into the German Aerospace Center (DLR) in June 2017. The primary research objective of the three scientific departments Urban and Residential Technologies, Energy System Technologies and Energy Systems Analysis is to ensure the development of technologies and concepts for managing the energy transition. The Institute currently employs around 170 staff at two locations in Oldenburg and Stuttgart.


Hartmann Valves GmbH is a supplier of special ball valves, wellheads and related service and testing. The medium-sized family-owned company is managed by the third generation and employs 200 people at its German sites in Celle and Burgdorf. Thanks to decades of international experience in the oil & gas, storage technology and (petro)chemical industries, Hartmann Valves is a sought-after pioneering partner for the switch to renewable energies - both in the field of deep geothermal energy and in solutions for applications and underground storage of hydrogen.


For more than 30 years, the Chair of Geomechanics and Multi-Physical Systems at Clausthal University of Technology has been working on the stability and tightness of salt caverns for storage of energy raw materials such as natural gas and crude oil, for compressed air energy storage and for brine production. The verification of stability and tightness is based on extensive and complex numerical calculations, in which the caverns and the cavern operation pattern are simulated according to real conditions. The chair has one of the world's most efficient rock physics laboratories with more than 25 triaxial testing facilities for the analysis of the thermal-mechanical-hydraulic coupled material behavior of the rock mass. For the performance of its tasks in research and teaching, the chair has an extensively equipped laboratory (currently 25 rock mechanical testing facilities), a powerful computer pool and various numerical program systems.


SOCON Sonar Control Kavernenvermessung GmbH, based in Giesen (district of Hildesheim), is a globally active service company and specializes in the surveillance of caverns, boreholes and underground cavities using engineering surveying techniques. It has around 80 employees and can look back on over 50 years of experience in the field of echometric cavern surveying. All essential components of the tools, measurement and evaluation systems originate from the company's own research and development department.