The Dutch gas supplier Gasunie plans to store green hydrogen from solar and wind energy in underground salt caverns. The project is called "HyStock".
In Zuidwending near Groningen in the Netherlands, Gasunie plans to use four salt caverns to store hydrogen in the future. Compressor stations will then feed around 76 million cubic meters of hydrogen gas into each of the planned caverns, creating a total storage capacity of around 26 million kg of hydrogen. Right next door, six caverns already exist to store natural gas.
Currently, the facilities and the feasibility of HyStock are being tested on a first well. The effects of hydrogen on the equipment, material, cement and salt walls are being studied. Tests are also being carried out to ensure that the quality of the hydrogen is not impaired and that all safety requirements are met. Bilfinger is the partner for the technical equipment. The Group has a great deal of experience in the construction of natural gas storage facilities.
The Eiffel Tower could easily fit into the salt caverns in Zuidwending. The upper end of the caverns lies at a depth of around 1,200 meters. For gas storage, however, the huge caverns need a different shape than is created when the salt is mined. For this purpose, they are washed out with water until an elongated, cigar-like shape is created. The distances between the individual caverns must also be greater than during salt mining.
Salt caverns are a simple and inexpensive way to store large quantities of hydrogen. The efficiency is around 98 percent. The first HyStock cavern is scheduled to go into operation by 2026 at the latest and will then be able to store around 6,000 metric tons of hydrogen or 200 gigawatt hours. The other three hydrogen caverns in Zuidwending are to be added by 2030.