Germany is drilling salt caverns more than 1.000 m deep to store green hydrogen; projects could reach hundreds of GWh and support the European energy transition.
Germany is accelerating the creation of an underground infrastructure dedicated to large-scale green hydrogen storage, utilizing saline caverns located more than 1.000 meters deepThe goal is to transform natural geological formations into energy reservoirs capable of storing volumes equivalent to hundreds of gigawatt-hours (GWh), creating a strategic base to stabilize the national electricity system and support industrial decarbonization.
The country, considered the largest economy in Europe, has set ambitious goals to reduce emissions and expand the use of renewable energy. However, sources such as wind and solar are intermittent. On days with excessive wind or sun, production exceeds demand; during periods of calm or low solar incidence, the opposite occurs. Hydrogen storage emerges as one of the main tools to compensate for these variations.
Why are salt caves chosen for hydrogen storage Verde
Germany has extensive underground salt formations, especially in the north of the country. These geological structures, called salt domes or salt layers, have ideal properties for storing gases under high pressure.
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Salt is virtually impermeable and has a natural capacity for structural self-regeneration, which reduces the risk of leaks. For decades, these caverns have been used to store natural gas and oil. The adaptation for hydrogen takes advantage of this accumulated experience.
The caves are created through a process called leaching, in which water is injected into the saline deposit to dissolve the salt and form large underground cavities. Then, the space is prepared to receive compressed gas.
Each cave can reach volumes greater than 500.000 cubic metersdepending on the geological formation and the engineering applied.
Depth and operating pressure
Storage typically occurs between 1.000 and 1.500 meters deepwhere the natural pressure of the subsoil helps to keep the hydrogen compressed. Under these conditions, the gas can be stored stably for long periods.
Operating pressure may exceed 200 bar, requiring highly sophisticated control and monitoring systems.
This depth also contributes to thermal stability and structural safety.
One of the main development hubs is in the Etzel region of Lower Saxony. The project known as H2CAST Etzel has begun real-world tests of hydrogen injection in adapted caverns.
In the initial phase, approximately [number] were injected. 90 tons of hydrogenallowing for the evaluation of the physicochemical behavior, stability, and integrity of the structures.
The future expansion goal envisions that individual facilities may reach a capacity close to 1 terawatt-hours (TWh)equivalent to the annual consumption of tens of thousands of households.
Another important center is in the Epe region of North Rhine-Westphalia, where energy companies are planning to convert existing caves for the exclusive use of hydrogen.
Projected national capacity
Studies by the German Ministry of Economy indicate that the need for storage could reach between 70 and 80 TWh by 2045…if hydrogen becomes established as a central energy vector for heavy industry.
For comparison, 1 TWh corresponds to 1 billion kWh. This means that the projected storage involves energy volumes equivalent to the annual production of large power plants.
The expansion of salt caverns could allow for capacities on the order of hundreds of GWh per unit, creating a scalable modular system.
The strategic role of green hydrogen.
Green hydrogen is produced through water electrolysis using renewable energy. When there is surplus wind power generation in northern Germany, for example, the electricity can be used to produce hydrogen, which is then stored.
Later, this hydrogen can be:
- Used in the steel industry to replace coal.
- Used in the production of ammonia and fertilizers.
- Converted back into electricity by means of turbines or fuel cells.
- Injected into specific industrial networks
This flexibility transforms hydrogen into an element of integration between the electrical, industrial, and heavy transport sectors.
Germany is also involved in creating a network of hydrogen pipelines connecting the Netherlands, Belgium, and Denmark.
Underground infrastructure functions as a regional strategic reserve. During periods of high renewable production, the stocks can be replenished. In times of high demand, hydrogen can be released to sustain the economy.
This model reduces dependence on fossil fuel imports and strengthens energy security.
Lithium batteries are widely used for short-term storage, but have limitations for seasonal volumes.
Salt caves offer much greater capacity per unit of cost, making them suitable for storage for weeks or months.
Furthermore, hydrogen allows for transportation via pipelines, something that is not feasible for electrical energy stored in batteries.
Technical challenges
Despite the advantages, hydrogen storage presents specific challenges:
- Hydrogen has a very small molecule, requiring a tight seal.
- It can cause embrittlement in some metals.
- Requires constant monitoring of pressure and structural integrity.
German companies are developing coatings and digital control systems to mitigate these risks. The development of this infrastructure involves billions of euros in investment.
The conversion of caverns, construction of compression stations, and integration with gas pipelines have a direct impact on the energy industry.
Furthermore, it creates a structural basis to attract industries that depend on green hydrogen.
Projection until 2045
The German energy plan envisions climate neutrality by mid-century.
To achieve this goal, storage capacity needs to keep pace with the growth of renewable production. Salt caverns represent a large-scale solution to support this structural transformation.
Consolidated technical data
- Typical depth: 1.000 to 1.500 meters
- Operating pressure: up to 200 bar
- Capacity per cavern: hundreds of GWh
- National target by 2045: by 80 TWh
- Basic technology: salt leaching + hydrogen compression
A Germany is converting natural geological formations into strategic energy reservoirs., drilling deep salt caverns to store green hydrogen in industrial volumes.
With targets reaching tens of terawatt-hours by 2045, these underground megaprojects position the country as one of the world’s leading centers for large-scale energy storage.
By integrating renewable production, seasonal storage, and regional distribution, the German model creates an infrastructure capable of supporting the energy transition of Europe’s largest economy.
