Hydrogen storage project enters the next phase

13.05.2025

Source: E & M powernews

Gasunie and Storag Etzel are starting to fill the hydrogen cavern in Etzel, Lower Saxony. Construction of the above-ground facilities is also due to start soon.

The operators Gasunie and Storag Etzel have reached the next milestone in the "H2CAST Etzel" pilot project: filling of the two existing salt caverns, which are being converted for hydrogen storage, has begun. This is according to a statement from the companies.

A total of 90 tons of hydrogen are now to be filled into the caverns, which hold around 300,000 cubic meters. The aim is to develop and operate a flexible underground storage facility with a total capacity of up to 1 billion kWh of hydrogen.

The project was launched in 2023. In the first phase - "H2CAST Ready" - the suitability of the caverns and the tightness of the underground materials for use as an underground hydrogen storage facility was demonstrated by filling them with hydrogen (we reported).

With the start of work on the above-ground facility, the "H2CAST Prove" project phase will now continue as planned, which is intended to prove that the facilities are operating as intended and guarantee the desired hydrogen quality.

The hydrogen is supplied by the service provider Plug Power from Werlte, around 90 kilometers south of Etzel, also in Lower Saxony. Under a contract with Gasunie, Plug Power will supply around 45 tons of hydrogen in approximately one to two truckloads per day between April and August 2025, the company writes on its website.

The hydrogen is produced using electrolysis from electricity from the grid, with most truck refueling taking place at midday, when Germany's supply of renewable energy is at its peak. This schedule helps to minimize CO2 intensity, the company writes.

Flexibly scalable

"With H2CAST, a research project has been launched in which underground storage in caverns is being tested on an industrial scale," commented Boris Richter, Managing Director of Storag Etzel, on the milestone achieved. "Through H2CAST, we are gaining important insights as a blueprint for the conversion of further caverns for hydrogen storage in Germany and gathering the necessary operating experience."

The Etzel site already stands out as an "energy hub" with an existing connection to the European natural gas grid. Etzel is also located in the immediate vicinity of Germany's only deep-water port in Wilhelmshaven with corresponding H2-capable pipeline connections, which will also play an important role in the H2 core network for hydrogen imports in the future.

Richter sees the pilot project as just the beginning: "The Etzel caverns are flexibly scalable, meaning that existing local underground gas and oil storage facilities can also be repurposed for the use of hydrogen. The expansion options for the project are correspondingly diverse. One thing is certain: the underground storage of hydrogen in caverns on a large scale works. We will be ready when the H2 market is there."

Author: Katia Meyer-Tien