EWE press release from 29 October 2021
Construction work on the first EWE hydrogen cavern continues on Monday. The house-sized test cavern is being built in Rüdersdorf near Berlin on the site of the gas storage facility. After EWE installed and cemented in a pipe-in-pipe system as a hydrogen supply line to a depth of 1,000 metres in the spring, the energy service provider will insert two more pipes into the pipe system, which is firmly connected to the salt dome, by the end of the year. EWE is erecting another drilling rig to insert the smaller pipes. Water is to be channelled into the depths via the pipes to be inserted from March.
With the help of the water, the 500 cubic metre underground cavity in the salt dome is created over a period of around three months in what is known as the brine process. Energy service provider EWE wants to use it to test and prove the safe storage of 100 per cent hydrogen. "With the HyCAVmobil research project, we are taking on a pioneering role in Europe. There are many considerations and project ideas, and we are already taking action and implementing them," says EWE hydrogen ambassador Paul Schneider. Findings from the project could be transferred to large cavern storage facilities. With 37 salt caverns, EWE has 15 per cent of all German cavern storage facilities that could be suitable for storing hydrogen in the future. This would be an important basis for making large quantities of green hydrogen produced from renewable energies storable and usable in line with demand and for achieving the climate targets that have been set.
Three-month brine process for 500 cubic metres of mini cavern
The brine process for the hydrogen test cavern is no different to a brine process for conventional natural gas storage facilities. Only the duration of the brine process is significantly shorter. "Once we have connected the upper end of our pipe system, the wellhead, to the brine process, we will create the 500 cubic metre cavity in the salt dome in just three months. Our existing 37 cavern storage facilities, in which we have been storing and withdrawing natural gas for many years, are a thousand times larger. The Eiffel Tower would fit into them. It usually took us two and a half years to build them," explains Paul Schneider.
The rock salt layer beneath the storage site in Rüdersdorf, where EWE has already built two large cavern storage facilities, begins at a depth of around 600 metres and reaches up to 3,200 metres below the earth's surface. The salt comes from a sea that existed in Rüdersdorf 250 million years ago. The cavity is washed out with water from its own pond and from the mill stream flowing past. "We will use 4,000 cubic metres of fresh water over a period of three months to brine our test cavern. We will pump the salt water produced during the brine process to our injection station in Heckelberg via an existing underground pipeline. There, the brine is channelled into sandstone formations 1,000 metres deep, which already contain salt water by nature," says Schneider, explaining the process.
Research project for proof of quality
Before large-scale hydrogen storage is possible, EWE wants to prove that hydrogen can be stored safely in underground cavities and is of the appropriate quality for future applications once it has been extracted. Paul Schneider: "For large-scale hydrogen storage, we first have to prove to the relevant authorities that hydrogen is compatible with the materials used and is safe in the long term. In addition, our tests are particularly important for the use of hydrogen, for example in the mobility sector." In the course of the research project, EWE is particularly hoping to gain insights into the degree of purity of the hydrogen after it has been extracted from the cavern. This criterion is particularly important for hydrogen applications in the mobility sector. The development of a hydrogen economy is an absolutely necessary step towards a sustainable and climate-friendly energy system.
EWE is cooperating with the German Aerospace Centre (DLR) on the project. Among other things, the DLR Institute of Networked Energy Systems is analysing the quality of the hydrogen after it has been extracted from the cavern and the materials used. The investment volume amounts to around ten million euros - four million of which are EWE's own funds. EWE and DLR will receive the remaining sum as funding from the Federal Ministry of Transport and Digital Infrastructure as part of the National Innovation Programme for Hydrogen and Fuel Cell Technology.
Media contact:
Nadine Auras
Tel.: 03341 / 382 - 103
Mobile: 0162 / 1331144
Mail:
nadine.auras(at)ewe.de