HPC Krummhörn

Storing hydrogen - Why?

Being able to store hydrogen in large quantities means making renewable energy sources flexibly available. This is essential for a decarbonised energy system in the future and the development of a hydrogen industry in Germany. We have been using large-scale storage facilities for the safe storage of natural gas for decades. We are testing underground hydrogen storage in caverns with the HPC Krummhörn project.

The Background

The storage of hydrogen in salt caverns has so far only been used sporadically in the USA and the UK. Especially for operational use with cyclical injection and withdrawal, there is not enough experience in Germany. The manufacturers do not have sufficient specifications regarding material compatibility and certifications for operation with hydrogen.

This is why we test geological conditions and all plant components for their compatibility with hydrogen in a specially constructed pilot cavern.

The experience gained here will then form the basis for larger-scale projects and the foundation for the construction of further, then commercial, hydrogen caverns at other locations.

Project description

Commissioning of the demonstration plant in 2024
Storage volume of up to 500,000 Nm³ hydrogen - corresponds to 1,8 GWh
Testing the operation and technology of 100% H2 storage in real environment
Understanding of the approval procedures and requirements
Investigation of materials, underground and above-ground installations, and the functionality of individual components in H2 storage operation.
Development of a storage solution for renewable hydrogen on a commercial scale

Process stages

Assessment of the status of the borehole and performance of a two-stage gas tightness test

1) Status of the borehole

Evaluate the status of the borehole and perform a two-stage gas tightness test.

For the construction of the H2 pilot cavern, we are using the existing storage well K6. Before starting work on the cavern site, we examine the existing components of the well in various material tests to determine their suitability for hydrogen storage operation. First, we use a workover rig to restore access to the open hole and create a defined continuous borehole diameter in the uncased borehole area that is part of the test area. In addition, we subject the well to a two-stage gas tightness test using the test media nitrogen and hydrogen.

2) Solution mining phase

Creating a cavern by leaching

During the brine phase, we will create a pilot cavern with a geometric void volume of approximately 3,000 m³ in the lower section of the well. This configuration allows for a possible later re-solving to enlarge the cavern in order to be able to use the cavern commercially for hydrogen storage after the pilot phase. For the brine-out phase, the necessary brine-technical installations will be installed and the cavern will be connected to the brine station via the field pipeline system. In order to specifically develop the cavern shape, we use nitrogen as blanket medium.

3) Hydrogen leak test

Hydrogen leakage test and installation of a hydrogen storage completion

After the pilot cavern has been built, the solar installations will be removed and the cavern will be subjected to a new leak test with hydrogen as a medium. The test pressure corresponds to the later storage operating pressure. Afterwards, we convert the cavern for hydrogen operation. In this context, we install, among other things, a hydrogen production pipe tour with special underground components and a hydrogen wellhead. On the surface, we connect the cavern via the field pipeline system to the storage station, where the hydrogen storage components are installed.

4) Initial hydrogen filling

Initial hydrogen filling and subsequent pilot storage

To evaluate the various planned tests, the operating conditions and the hydrogen suitability of the components, we install appropriate measuring equipment. After commissioning all components, we then fill the cavern with hydrogen for the first time. The brine that is still in the cavern at this point is displaced by the hydrogen and brought to the surface via a brine drainage line. After complete filling, the brine drainage line is removed from the cavern under pressure using a so-called snubbing system. The operating phase of the hydrogen pilot cavern then begins.

Project Milestones

Foto mit dem Föderbescheid für das H2-Speicherprojekt in Krummhörn

Funding letter

After a feasibility study, Lower Saxony’s Environment Minister Olaf Lies granted €2.375M on July 25, 2022 for Uniper’s hydrogen pilot at Krummhörn, calling it ‘a key part of Germany’s energy transition.’

Schaffung einer Kaverne durch Aussolung - Pumpenhaus

Creating a cavern through leaching

January - March 2024

Massive underground salt deposits were leached for 8 weeks, creating a 3,000 m³ cavern (30 m high, 16 m diameter). It can store nearly 500,000 Nm³ of hydrogen—about 1.8 GWh.

Einbau einer wasserstoffverträglichen Komplettierung

Installation of a completion

From April to May 2024, a workover took place in which the brine pipes were removed and the hydrogen-compatible completion was installed.

Opening

August 2024

Olaf Lies, Lower Saxony's Minister for Economic Affairs, alongside our CEO Michael Lewis and other distinguished guests, inaugurated the facility.

Leak test

October 2024

Carrying out a second gas leak test with hydrogen

Energy Transformation Hub Nordwest

With the Energy Transition Hubs, Uniper has created technology and exchange platforms - our Energy Transformation Hubs. At these hubs, we are engaging with both local and national stakeholders, and working with our partners in business and industry to reduce CO2 emissions, secure the energy supply for the future and drive forward sector coupling. At selected locations, we are working with our partners on innovative solutions focusing on hydrogen and other low-CO₂ gases. One of these locations is Krummhörn, which is part of the Energy Transformation Hub Nordwest. The Energy Transformation Hub Nordwest bundles Uniper's major projects for supply security and hydrogen in Wilhelmshaven and the surrounding area.

more about the Energy Transformation Hubs

Our other hydrogen projects

HyStorage

In our HyStorage research project, we are testing the integrity of porous rock storages for hydrogen storage. At our Bierwang site in Bavaria we examine the influence of different hydrogen concentrations on porous rock formations. The measurement data and results generated, will help to fundamentally assess the suitability of the storage location for the future storage of hydrogen.

Go to Hystorage