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Salt Caverns Store Hydrogen for the Mobility Revolution

By December 26, 2020 5   min read  (936 words)

December 26, 2020 |

Salt Caverns
  • In the HyCAVmobil project, DLR is researching how hydrogen can be stored safely and sustainably in salt caverns. It will then be used in vehicles with fuel cells.
  • The DLR Institute for Networked Energy Systems will test the purity of the hydrogen when it is fed in and out under controlled, real conditions.
  • A requirements analysis and special operating concepts serve to integrate the hydrogen cavern into the existing energy system in the best possible way.
  • Focus: energy, energy storage, hydrogen

In the HyCAVmobil (Hydrogen Cavern for Mobility) project, the German Aerospace Center (DLR) is researching and evaluating how hydrogen can be stored in salt caverns and then used in vehicles with fuel cells. Tests on a laboratory scale are followed by tests on a test cavern operated by the energy company EWE.

“Green” hydrogen has enormous potential as an energy carrier: It can store electricity from renewable energies and can be reliably stored for a long time. Large storage facilities will be an essential part of a future hydrogen infrastructure. With their help, seasonal peaks in demand, such as the beginning of the heating season or dark doldrums, can be safely covered. “Germany already has natural gas storage facilities in underground salt caverns. Together with EWE gas storage, we are examining how we can also use these storage facilities for hydrogen. To do this, we examine and optimize materials, components, modes of operation and user requirements, ”explains Prof. Carsten Agert, Director of the DLR Institute for Networked Energy Systems in Oldenburg.

In the Brandenburg town of Rüdersdorf near Berlin, EWE gas storage is building a small cavern storage facility in the salt rock at a depth of around 1,000 meters. Only hydrogen is to be stored there. Construction will begin in early 2021. First research results are expected in 2022. “As an energy service provider , EWE sees itself as having a special responsibility. The energy sector must offer industry and other private and commercial consumers alternative and, as far as possible, CO 2-free energy, ” emphasizes EWE CEO Stefan Dohler.

DLR will then test the purity of the hydrogen when it is fed in and out under controlled, real conditions. With 500 cubic meters, the cavern has about the volume of a single-family house. The scientific findings can be transferred to caverns with 1,000 times the volume. “The aim of the project is to be able to use some of the ‘large’ EWE natural gas caverns as storage for hydrogen in the future,” explains project manager and DLR researcher Dr. Michael Kröner the long-term perspective.

High quality hydrogen for electromobility

Drives with fuel cells are a sustainable alternative wherever petrol, diesel, kerosene or heavy oil are used today. Hydrogen for fuel cells must be of particularly high purity. Even the smallest impurities affect the functioning of the fuel cell. Pressure and temperature in combination under the specific conditions of the salt cavern can have an influence on the materials used, for example metals or sealants. If substances are released from this, they can contaminate the stored hydrogen. That is a question that the

DLR Institute for Networked Energy Systems is investigating. In the first step, the DLR researchers simulate the salt cavern in terms of pressure and temperature. “Under laboratory conditions we have the advantage that we can precisely determine the purity of the hydrogen before and after storage with the help of trace gas analysis, ”explains Michael Kröner. “In our high-pressure test reactors we can test the reaction of many materials with hydrogen in combination with gas analysis”. It is important here whether the hydrogen still meets the high quality and purity requirements for fuel cell mobility after it has been stored in the cavern. If the hydrogen is contaminated, the project team is also investigating physical gas filter processes. 

These can restore the purity of the gaseous hydrogen. “In our high-pressure test reactors we can test the reaction of many materials with hydrogen in combination with gas analysis”. It is important here whether the hydrogen still meets the high quality and purity requirements for fuel cell mobility after it has been stored in the cavern. If the hydrogen is contaminated, the project team is also investigating physical gas filter processes. These can restore the purity of the gaseous hydrogen. “In our high-pressure test reactors we can test the reaction of many materials with hydrogen in combination with gas analysis”. It is important here whether the hydrogen still meets the high quality and purity requirements for fuel cell mobility after it has been stored in the cavern. If the hydrogen is contaminated, the project team is also investigating physical gas filter processes. These can restore the purity of the gaseous hydrogen.

Further questions are which systems and regulations are necessary to feed the hydrogen in and out under pressure in the cavern and how stable renewable energies can continuously supply the necessary electricity. It would also be conceivable to produce and store sustainable hydrogen directly on site using electrolysis. Against this background, DLR is modeling the upstream power grids at the cavern location and determining requirements and operating concepts in order to integrate the hydrogen cavern into the existing energy system as best as possible.

The HyCAVmobil project is funded by the Federal Ministry of Transport and Digital Infrastructure (BMVI) with a total of almost six million euros as part of the National Innovation Program for Hydrogen and Fuel Cell Technology, of which DLR receives one and a half million euros. The funding guidelines are coordinated by the National Organization for Hydrogen and Fuel Cell Technology (NOW) and implemented by Project Management Jülich (PtJ).

Source: DLR

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