Hydrogen drying by absorption

Hydrogen drying by absorption



©UniperSource: Bilfinger

Bilfinger's hydrogen drying plant will enable large-scale hydrogen treatment.

Decentralized hydrogen drying by absorption

The storage of green hydrogen is a central instrument to ensure the security of supply with renewable energies. Cavern storage facilities can offer suitable storage options - especially in Lower Saxony. However, in order to be able to convert the hydrogen back into electricity or feed it from the caverns into the pipeline network, it must first be dried. In this connection, Bilfinger is currently developing a demonstration plant in Cloppenburg in which the hydrogen is freed from moisture by absorption. This so-called "absorption drying" is already being implemented on a large scale for natural gas for gas storage - and is now also to be used for drying large quantities of hydrogen.

News (26.05.2023): Projekt zur Wasserstoff-Speicherung erreicht nächste Phase: H2dry Anlage von Bilfinger wird am EWE Gasspeicher-Standort in Rüdersdorf aufgebaut

Bilfinger hat in Cloppenburg eine Demonstrationsanlage entwickelt, in welcher der Wasserstoff durch Absorption von Feuchtigkeit befreit wird.

Die sogenannte „H2dry Anlage“ wurde nun zum Gasspeicherstandort der EWE AG nach Rüdersdorf bei Berlin geliefert, wo die Speicherung von Wasserstoff in unterirdischen Kavernen exemplarisch getestet wird. Die Erkenntnisse sollen auf Kavernen mit dem 1.000 fachen Volumen übertragen werden können. Mehr erfahren

The drying process developed in the project enables efficient and large-scale hydrogen treatment, which is essential for the storage and subsequent grid feed-in of green hydrogen. Since the technology has already been tested in the context of natural gas drying, the plant can also be used to dry large quantities of hydrogen cost-effectively, which are necessary for the development of the hydrogen economy. After storage - for example from caverns - the hydrogen is dried in the absorption drying process using a suitable scrubbing liquid and can then either be used to generate electricity or fed into the transport network. The plant should enable hydrogen to contribute to the energy supply in a similarly flexible way as natural gas.

The joint project of Bilfinger Engineering & Maintenance GmbH and the Institute of Thermodynamics at Leibniz Universität Hannover is funded by the state of Lower Saxony and is an important part of the energy transition, as Lower Saxony's Environment Minister Olaf Lies emphasizes: "The implementation of this project is a major step for the energy transition. Decentralized hydrogen drying by absorption for gas storage and grid injection, is an essential step for the hydrogen economy. With this technology, hydrogen can be treated economically on a large scale and this enables the integration of renewable energies into our energy system. For example, hydrogen produced using wind and solar power, or hydrogen soon to be stored in caverns, can be fed into the transportation grid."

After production at Bilfinger Engineering & Maintenance GmbH in Cloppenburg, Lower Saxony, a test phase and demonstration operation will follow in early 2023 in Rüdersdorf in Brandenburg, where EWE Gasspeicher GmbH is currently investigating a salt cavern as a potential storage site for hydrogen as part of the HyCAVmobil project.

More about the project

Project participants

Bilfinger is an internationally active industrial services provider. The aim of the Group's activities is to increase the efficiency of plants in the process industry, ensure their availability, reduce emissions and lower maintenance costs. Bilfinger offers services in various areas, from consulting, engineering, manufacturing, assembly and maintenance to environmental technologies and digital applications.

Bilfinger Engineering & Maintenance GmbH is part of the international Bilfinger Group and is active in industrial services. More than 3,000 employees plan and monitor plants in the process industry in the chemical, petrochemical and pharmaceutical sectors, among others.

The Gottfried Wilhelm Leibniz Universität Hannover is Lower Saxony's largest university with around 30,000 students. The Institute of Thermodynamics represents technical thermodynamics in the Faculty of Mechanical Engineering at Leibniz Universität Hannover in teaching and research.


Hydrogen Cavern for Mobility

Hydrogen Cavern for Mobility


HyCAVmobil (Hydrogen Cavern for Mobility) - Investigation of salt caverns as a potential storage site for hydrogen

News (13.03.2023): EWE stellt Wasserstoff-Testkaverne fertig und will im Spätsommer mit der Wasserstoffeinlagerung beginnen!

As EWE announced last week, the hydrogen test cavern in Rüdersorf near Berlin has been successfully completed. Over the past three months, an underground cavern with a volume of about 500 cubic meters has been created and various leak tests have been successfully implemented. The initial filling with hydrogen and extensive test operation of the cavern are scheduled for late summer this year. The project, called "HyCAVmobil", is intended to provide important findings that can also be transferred to larger caverns with 1,000 times the volume, such as those that exist in Lower Saxony. This should eventually make large-scale hydrogen storage possible.

Learn more: https://www.ewe.com/de/media-center/pressemitteilungen/2023/03/wasserstoffkaverne-ist-fertiggestellt-ewe-ag

News (26.05.2023): Projekt zur Wasserstoff-Speicherung erreicht nächste Phase: H2dry Anlage von Bilfinger wird am EWE Gasspeicher-Standort in Rüdersdorf aufgebaut

Bilfinger hat in Cloppenburg eine Demonstrationsanlage entwickelt, in welcher der Wasserstoff durch Absorption von Feuchtigkeit befreit wird.

Die sogenannte „H2dry Anlage“ wurde nun zum Gasspeicherstandort der EWE AG nach Rüdersdorf bei Berlin geliefert, wo die Speicherung von Wasserstoff in unterirdischen Kavernen exemplarisch getestet wird. Die Erkenntnisse sollen auf Kavernen mit dem 1.000 fachen Volumen übertragen werden können. Mehr erfahren

For a reliable supply of clean hydrogen, a holistic infrastructure must be built, as is also the case with fossil gases. In addition to the expansion or conversion of the grid, this also includes the storage of the gas. How we can reliably store hydrogen in the long term is becoming increasingly important for sector coupling.

The HyCAVmobil project of EWE Gasspeicher GmbH and the German Aerospace Center (DLR) Institute for Networked Energy Systems is therefore looking at the sustainable and safe storage of 100 per cent pure hydrogen in salt caverns - a pioneering project.

Currently, salt caverns are used as safe long-term storage for energy sources such as natural gas or crude oil. In the context of the energy transition, this type of storage is now also being considered for hydrogen. In order to store hydrogen in the long term and then use it in the field of fuel cell mobility, the HyCAVmobil (Hydrogen Cavern for Mobility) project will research the conditions under which pure hydrogen can also be stored in salt caverns. The main focus is on how storage and retrieval affect the quality of the hydrogen.

Following initial laboratory-scale investigations, EWE and its Lower Saxony project partner have been building an underground cavern storage facility in Rüdersdorf, Brandenburg, since February 2021. In a first step, a drilling rig is erected and the salt dome is flushed out with water at a depth of 1,000 meters. This will create a cavity of 500 cubic meters, in which up to six tons of hydrogen will be stored in the future. By way of illustration, this quantity is enough to fill up around 1,000 hydrogen cars. If the project is successful, the findings of this project can easily be transferred to caverns with 1,000 times the volume, according to those responsible. That would be an important step toward large-scale hydrogen use.

The project is funded as part of the National Hydrogen and Fuel Cell Technology Innovation Programme and receives a funding grant of around 6 million euros from the Federal Ministry of Transport and Digital Infrastructure (BMVI).



©Ahrens Roof Technology
©DLR Institute for Networked Energy Systems

With approximately 9,100 employees, the EWE AG one of the largest utility companies in Germany, which focuses on the corresponding infrastructure in the hydrogen sector.

Logo: © EWE AG



The Oldenburg Institute for Networked Energy Systems develops technologies and concepts for the future energy supply based on renewable energies. This transformation process is being researched taking into account the aspects of "defossilisation", "decentralisation" and "digitalisation".

Logo: © DLR Institute for Networked Energy Systems



Clean Hydrogen Coastline

Clean Hydrogen Coastline


About 400 megawatts of electrolysis capacity will be built in the Clean Hydrogen Coastline project in the Northwest region by 2026. Image source: ©EWE

Clean Hydrogen Coastline

The German North Sea coast is of particular importance in the development of a nationwide hydrogen economy. Due to the high supply of renewable energies, hydrogen can not only be produced in the region, but also stored, integrated into the energy system via existing electricity and gas infrastructure, or used directly on site. The "Important Project of Common European Interest" (IPCEI) "Clean Hydrogen Coastline" is intended to contribute to the development and expansion of the hydrogen economy in the Northwest region.

News (04.05.2023): EWE und Salzgitter AG wollen beim Thema Wasserstoff kooperieren!

Am 04.05.2023 haben die Salzgitter AG und der Versorger EWE in Salzgitter eine Absichtserklärung unterzeichnet, die eine Kooperation der beiden Unternehmen beim Thema Wasserstoff vorsieht. So will EWE grünen Wasserstoff erzeugen und nach Salzgitter liefern, den die Salzgitter AG dann für die klimafreundliche Stahlerzeugung im Rahmen des Projekts SALCOS® einsetzt. Die Absichtserklärung wurde von den Vorstandsvorsitzenden Stefan Dohler (EWE) und GUnnar Groebler (Salzgitter AG) im Rahmen des Handesblatt Wasserstoff-Gipfels unterzeichnet.

Mit der Kooperation werden auch die beiden niedersächsischen Groß-Projekte Clean Hydrogen Coastline von EWE und SALCOS® von der Salzgitter AG stärker vernetzt, was auch der niedersächsische Ministerpräsident Stephan Weil begrüßt: „EWE und die Salzgitter AG wollen eng kooperieren in Sachen grüner Wasserstoff – das ist eine sehr gute Neuigkeit für das Energieland Niedersachsen. Diese Kooperation ist ein weiterer Meilenstein auf dem Weg zur Dekarbonisierung der Stahlproduktion. Ich freue mich, dass die EWE mit der Erzeugung und dem Transport von grünem Wasserstoff das Leuchtturmprojekt SALCOS® der Salzgitter AG entscheidend voranbringt.“

Learn more

In the IPCEI "Clean Hydrogen Coastline", the industry partners ArcelorMittal, EWE, Faun, Gasunie, swb and Tennet want to build 400 megawatts of electrolysis capacity in the Northwest region by 2026. To this end, there are various projects to help with implementation.

For example, the hydrogen generated by offshore electricity will be used, among other things, for climate-neutral steel production at the Bremen steel site. If required, surplus hydrogen can be temporarily stored by connecting it to the cavern storage facility in Huntorf.

Clean Hydrogen Coastline's many links, for example with the Dutch partners, but also with projects in Hamburg and North Rhine-Westphalia, offer extensive potential for a European IPCEI. This will enable the partners to take a decisive step towards becoming an important building block of a future European hydrogen economy. The main goal of the project is to Integration of hydrogen into existing energy infrastructures.



ArcelorMittal is an international steel producer with a production volume of seven million tonnes of crude steel (2019), employing around 9,000 people across Germany.

Logo: © ArcelorMittal


With around 9,100 employees, EWE AG is one of the largest utilities in Germany that focuses on the corresponding infrastructure in the hydrogen sector.

Logo: © EWE AG

TenneT TSO GmbH is a transmission system operator with a grid length of 24,000 kilometres and approximately 5,700 employees.

Logo: © TenneT TSO GmbH

©Gasunie Germany

Gasunie Deutschland GmbH & Co. KG is the transmission system operator responsible for an approximately 4,300 kilometre long transmission system.

Logo: © Gasunie Germany

swb AG is a regional utility company for Bremen and Bremerhaven with around 2,255 employees.

Logo: © swb AG

Northern Green Crane

Northern Green Crane


Source: Hydrogenious LOHC Technologies

Image: ©Hydrogenious LOHC Technologies Ltd.

Northern Green Crane

The Northern Green Crane project aims to link hydrogen production in Sweden with demand centers in Central Europe - including Lingen in the Emsland region. To this end, green hydrogen will first be produced in Sweden, which will then be made transportable and storable with the help of a liquid organic hydrogen carrier (LOHC). The LOHC is then shipped by sea via Rotterdam and the Ems to Lingen. There, hydrogen will be released from the LOHC in a planned dehydrogenation plant and made usable for local industry and fed into the local hydrogen pipeline network.

News (10/2022): H2 production site relocated from Spain to Sweden

As Hydrogenious LOHC Technologies GmbH announced at the beginning of October, the hydrogen production site of the "Green Crane" project will be moved from Spain to Sweden. This gives the project the new name "Northern Green Crane". Since Spain initially wants to meet its own national needs for green hydrogen, the project's H2 production site must be moved to Sweden, the company said. However, the hydrogen landing sites (such as Lingen) are not affected by the change.

According to the National Hydrogen Strategy, a large proportion of green hydrogen will have to be imported to meet Germany's hydrogen needs. The Northern Green Crane project aims to do just that on a large scale. The green hydrogen is to be produced in Sweden using renewable energies such as wind and hydropower and made transportable and storable with the help of LOHC technology.

The green hydrogen can thus first be brought to Rotterdam by sea and then transported to Lingen by barge. In Lingen, Hydrogenious plans to build a dehydrogenation plant that can release hydrogen from the LOHC at a capacity of 12 tons per day. The hydrogen produced in this way will then be made available to local industry or fed into the local hydrogen pipeline network as part of the GET H2 initiative.

Source: Hydrogenious LOHC Technologies

The project is expected to enable the supply of green hydrogen on an industrial scale from 2026. By using the LNG infrastructure, it should then be possible to supply up to 8,000 tons of green hydrogen per year.

The goal of Northern Green Crane is to establish a large-volume European value chain for green hydrogen using LOHC. The project is therefore funded by the Ministry of Economy and Climate Protection and has also been pre-selected as a Hydrogen IPCEI (Important Projects of Common European Interest) in 2021 (or its predecessor - see info box below).


Hydrogenious LOHC Technologies GmbH , based in Bavaria, was founded in 2013 and offers solutions for the safe and efficient transport of hydrogen with LOHC technology.

Vopak is a Dutch company involved in the storage and distribution of oil, gas and chemical products. The company wants to open up new value chains in the hydrogen economy and expand hydrogen mobility.

In the GETH2 project, a nationwide infrastructure with the coupling of all sectors is being developed. Regions with a high supply of renewables are to be directly connected to hydrogen production and consumption by means of the necessary infrastructure. 12 partners are involved in the project.

Hydrogen storage in Etzel

Hydrogen storage in Etzel



In Etzel, experts in the H2CAST joint project are investigating whether the local salt domes are suitable for storing large quantities of hydrogen. ©STORAG ETZEL


Energy storage facilities play a central role in security of supply. In Lower Saxony, there are underground salt caverns that have so far been used as oil and gas storage facilities. The joint project H2CAST in Etzel is now investigating whether these can also function as storage facilities for hydrogen and what conversions may be necessary for this. The project is financially supported by the Lower Saxony Ministry for the Environment, Energy, Building and Climate Protection.

News (02/17/2023): Successful completion of the first leak test with hydrogen at cavern in Etzel

Within the framework of the research project H2CAST has STORAG ETZEL together with project partners successfully completed the first gas tightness test with hydrogen on a cavern borehole.

Extensive material testing was carried out in preparation for the test and during the test phase. In total, the team introduced several thousand standard cubic meters of gaseous hydrogen from sustainable, "green" production into the well. The test period wassignificantly longer, at over two months, than is the case with comparable tightness tests under nitrogen. More

News (01/17/2023): Gasunie becomes partner in the H2CAST Etzel project

As STORAG ETZEL and Gasunie announced on 17.01.2023, Gasunie will become consortium partner in the project "H2CAST Etzel". Within the framework of the project, hydrogen storage in the Etzel salt caverns is to be made possible together with project partners. In a first step, two existing salt caverns will be upgraded for H2 storage and connected by an aboveground facility. Gasunie will be responsible for this aboveground facility. The pilot project is scheduled for completion in 2026.

Gas and oil are stored in so-called caverns at a depth of over 750 metres in the massive Etzel salt dome. These are artificially created cavities in underground mining. The hydrogen research & development project H2CAST Etzel aims to show that these caverns can store not only oil and gas, but also large quantities of hydrogen. The existing caverns will then hold up to 22.5 TWh of hydrogen. A sophisticated shuttle operation system between two caverns will help to variably adjust the storage volume and the pressure, among other things. The project on an industrial scale could lead the way for many other salt caverns in Europe.

H2CAST is the abbreviation for H2 Cavern Storage Transition, and stands for the conversion of existing caverns and facilities for the storage of hydrogen.

Boris Richter, STORAG ETZEL

"We want to make the Etzel site in Lower Saxony "H2-ready", i.e. prepare it for the foreseeable ramp-up of the hydrogen economy, which will help to decarbonise German industry, i.e. make it more CO2-free and climate-friendly. In this way, security of supply with CO2-free energy will be guaranteed in the future. The location is of crucial importance for north-western Europe in this regard.

The energy transition will need these large-scale storage facilities by 2030 at the latest, as H2 supply and demand will diverge in time and space. Our goal is to make the location sustainable for future generations!

Christian Rode, EKB Storage

Christian Rohde adds, "that extremely flexible, large-volume underground storage facilities are essential for the energy transition, as they act as a variable buffer to secure the supply chains and can be used between hydrogen production or

-import and the consumers on the market. The Etzel site is particularly predestined for this due to its existing infrastructural importance."

Olaf Lies, Energy Minister

"Hydrogen will be an integral part of the future energy economy. Without storage, this will not succeed. With H2CAST Etzel, we are promoting a pilot project on an industrial scale. A competent and experienced project consortium from industry and science has come together for this. What is special is that for the first time in Lower Saxony, existing caverns intended for oil and gas storage are to be converted for hydrogen. The intended brine shuttle operation has also not yet been implemented in this way. The pilot project is also the starting point for a possible local value chain. We are creating knowledge that is likely to be in demand elsewhere. With the funding, we are helping to ensure that we will continue to have a secure energy supply in the future, ultimately without oil and natural gas, and that we will maintain local value creation in the energy hub of Lower Saxony."

H2CAST Etzel Project Team 

  • STORAG ETZEL (supplier of cavern storage facilities)

STORAG ETZEL builds, maintains and leases underground storage capacity for gas and oil at the Etzel site in East Frisia. Tenants are national and European oil storage organisations and international companies from the energy sector. Among other things, a large part of the German crude oil reserve is stored in Etzel.

    • Gasunie (responsible for the surface plant)

    Gasunie is a European energy infrastructure company. Gasunie's network is one of the largest high-pressure pipeline networks in Europe, comprising over 17,000 kilometers of pipelines in the Netherlands and northern Germany. With its cross-border gas infrastructure and services, Gasunie enables the TTF, which has become the leading European gas trading point. Gasunie also offers other gas infrastructure services, including gas storage and LNG.

    • KBB (planning, construction and operation of underground storage facilities)

    DEEP.KBB is significantly involved in the planning, construction and operation of underground storage facilities in the salt for the storage of natural gas, mineral oil, gas and oil products as well as the storage of renewable energies, in particular compressed air and hydrogen. Main focus: Geology, rock mechanics, drilling and completion engineering, thermodynamics, brine engineering, tightness testing, cavern flooding, gas filling and reservoir engineering.

    • DLR - Institute for Networked Energy Systems

    The Institute for Networked Energy Systems joined the German Aerospace Center (DLR) in June 2017. The primary research goal of the three scientific departments Urban and Building Technologies, Energy Systems Engineering and Energy Systems Analysis is the development of technologies and concepts to shape the energy transition.

    • Hartmann Valves

    Hartmann Valves is a supplier of special ball valves, wellheads and related service and testing, including solutions for applications and underground storage of hydrogen.

    • Clausthal University of Technology

    The Chair of Geomechanics and Multi-Physical Systems at Clausthal University of Technology is concerned with the stability and tightness of salt caverns for the storage of energy raw materials such as natural gas and crude oil, for compressed air storage and for brine extraction. 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 programme systems.

    • SOCON

    SOCON Sonar Control Cavern Surveying specialises in the geophysical survey of caverns, boreholes and underground cavities.

    Schrand Energy Plant

    Schrand Energy Plant


    Prof. Dr. -Ing. Reckzügel (Professor at Osnabrück University of Applied Sciences, Professor of Innovative Energy Technology and Thermal Energy Technology), Patrick Wösten (Osnabrück University of Applied Sciences, research assistant in the project), Minister Meyer, Jörg Wilke (Managing Director "Northern Institute of Thinking") (second row), Timo Schrand (Managing Director of schrand.energy GmbH & Co. KG), Paul Hoffmann (Project Manager Hydrogen at schrand.energy GmbH & Co. KG.) (second row), Uwe Bartels (Former State Minister)

    Self-sufficient energy system in the building

    In Essen (Oldenburg), the company schrand.energy GmbH & Co. KG is planning a CO2-neutral and energy-autonomous, company-owned new building. The concept called Schrand Energy Plant is developed from the beginning as a modular, reproducible and scalable overall solution in order to be able to transfer it to other buildings.

    The Schrand Energy Plant uses a photovoltaic system to supply renewable energy to the respective company site. The excess energy is then used in a PEM electrolysis unit to split water into hydrogen and oxygen, store these gases temporarily in pressurized gas tanks, and then convert them into electrical power and heat in a hydrogen fuel cell as needed. The Energy Plant is thus intended to provide a total system consisting of energy storage, electrolyzer, fuel cell and hydrogen tank that can be adapted to the respective consumer.

    On March 7, Lower Saxony's Environment and Energy Minister Christian Meyer handed over the funding. Schrand.energy will receive funding of around 2.7 million euros for the implementation and the cooperation partner Osnabrück University of Applied Sciences 230,000 euros. 

    Environment and Energy Minister Christian Meyer: "Renewable energies are essential if we want to protect the climate. Sometimes, however, we have large quantities without being able to store them. The project kills two birds with one stone by combining solar energy and hydrogen technology: surplus solar energy can thus be reused, and hydrogen can be produced with renewable energies. That's good for the climate and your wallet, and it strengthens the local economy with cheap, clean energy."