Storage caverns with a volume of far more than 500,000 m³ have already long been used to store natural gas. Salt domes at depths of less than 800 m, and over 300 m thick, are most suitable for construction of these caverns. Many such domes are available in Schleswig-Holstein and Lower Saxony, whereas the coastal region in the North-East of Germany has only a few individual salt domes in South-Western Mecklenburg. As well as geological suitability, there are other site factors to consider: close proximity to existing wind parks in Northern Germany, to future offshore wind parks in German coastal waters, and to the existing power grid, sufficient fresh water supply for solution mining, and possibilities for disposal of the brine which this produces (close to the sea), unless this brine can be used as an industrial raw material.

Storage caverns are created in solution mining by means of boreholes in which a number of pipes are installed (fig. 5). With brine pipe sections which can slide with respect to each other, water is added to dissolve the rock salt mass, and the brine which this creates is conveyed to the surface. During this process, the roof of the cavern is protected from uncontrolled dissolving by means of a blanket of air, natural gas, or oil. The main factors relevant to the environment are the fresh water required when creating the salt cavern, and the brine which is produced. In the area of the North Sea coast, sea water is available for the leaching process. The brine produced can be channelled into the lower course of strong currents, and into the North Sea. As the salt content of the Baltic Sea is lower, higher costs can be expected in order to achieve acceptable dilution of the cavern brine in the immediate vicinity of disposal installations.