Hydrogen storage is crucial to the energy transition. It allows for a balance between production and consumption. Thanks to their high capacity, hydrogen storage facilities can offset seasonal fluctuations in renewable energy and bridge supply shortages. Storage facilities are therefore essential to the stability of an energy system and contribute significantly to security of supply.
Hydrogen can be stored both underground and above ground. This results in four possible types of hydrogen storage:
- Salt Caverns
- Porous storage
- Gasometer
- Ball storage tank
The choice of storage type depends on local conditions, the required capacity, and the intended use.
Salt Cavern
Construction of a salt cavern for hydrogen storage (© Uniper)
Salt caverns are underground cavities in salt domes that are suitable for storing large quantities of hydrogen. With a capacity of up to several hundred thousand cubic meters, they offer ideal conditions for long-term storage. This technology is already in use for natural gas storage and is now being adapted for hydrogen.
There are several regions in Germany with salt caverns that could potentially be used for hydrogen storage:
- Lower Saxony: Large salt dome deposits, particularly in the Wilhelmshaven and Etzel areas.
- Schleswig-Holstein: Cavern storage facilities in Heide and Kiel.
- Saxony-Anhalt: Salt formations in the Bernburg area.
- Thuringia: Cavern storage facility in Bad Lauchstädt.
- Mecklenburg-Western Pomerania: Potential sites in the Waren/Müritz region.
Porous storage
Structure of a pore-based hydrogen storage system (© Uniper)
Porous storage sites are natural underground rock formations suitable for storing enormous quantities of hydrogen. These are often depleted natural gas or oil fields with a storage capacity of up to several million cubic meters. One challenge is the potential contamination of the hydrogen by residual gases or minerals.
Potentially, porous storage systems could be used to store hydrogen in the following locations in Germany:
- Lower Saxony: Rehden, Etzel
- Bavaria: Bierwang, Breitbrunn
- Brandenburg: Rüdersdorf
- Saxony-Anhalt: Altmark
- Thuringia: Allmenhausen
Pforzheim Gasometer (© Wikimedia/Xocolatl, Pforzheim Gasometer at night, CC BY-SA 4.0)
Gasometer
Gasometers are above-ground cylindrical steel tanks that can be used for short- to medium-term hydrogen storage. They typically have a capacity of 10,000 to 200,000 cubic meters. Thanks to their movable roofs, gasometers often have a variable volume. This allows for flexible use and rapid availability during peak demand periods.
This type of gas storage facility is more commonly found in urban areas:
- North Rhine-Westphalia: Oberhausen, Duisburg
- Berlin: EUREF Campus
- Saxony: Leipzig-Connewitz
- Hamburg: Grasbrook Gas Works (historical)
- Saarland: Saarbrücken
Ball storage tank
Freiburg Gas Sphere Storage Facility (© Thomas Kunz)
Spherical storage tanks are above-ground, spherical pressure vessels suitable for the short-term storage of hydrogen. With a typical volume of 1,000 to 5,000 cubic meters, they tend to have a relatively small capacity. Their spherical shape ensures an optimal surface-to-volume ratio, which minimizes material costs and heat loss. Compared to gasometers, spherical storage tanks are more compact and can withstand higher pressures of up to 20 bar. Spherical storage tanks are more commonly found in industrial settings at industrial sites, ports, or along hydrogen pipelines. They are particularly well-suited for intermediate storage in production and distribution processes.
Possible locations for hydrogen spherical storage tanks in Germany:
- Hamburg: In the port, as part of the planned hydrogen infrastructure
- Leuna, Saxony-Anhalt: At the chemical plant, where hydrogen production is already underway
- Brunsbüttel, Schleswig-Holstein: In the industrial park, near the planned LNG terminal
- Duisburg, North Rhine-Westphalia: At the ThyssenKrupp steel mill, for hydrogen-based steel production
- Ingolstadt, Bavaria: At the refinery, as part of the hydrogen mobility strategy
Challenges
The construction of large-scale storage facilities requires significant investment and takes a great deal of time. In addition, storing hydrogen often requires technical modifications to existing infrastructure, which results in additional costs and effort.
Another disadvantage is the high degree of location dependency of hydrogen storage infrastructure. Not every location is geologically suitable for the construction of cavern or porous rock storage facilities, which severely limits the selection of potential sites.
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