For some years now, the world has been facing the challenge of achieving an energy turnaround in the coming years. In this context, renewable energies are increasingly coming into focus, also with regard to the construction and operation of storage caverns in rock salt. In order to be ready for these challenges from an engineering point of view, a lot of research work has been carried out in recent years in the sector of dimensioning salt caverns for the storage of renewable energies. At the Institute of Geotechnical Engineering at Leibniz University in Hanover, Germany, a test apparatus was created that allows fracturing processes to be induced in rock salt test specimens. Various rock salt locations were investigated in the process. Research work on this aspect will be completed in the near future. The results of the research project will be presented and their consequences for the future storage of renewable energies in salt caverns will be discussed from an engineering point of view. In addition to the maximum and minimum operating pressures of a storage cavern, the thermodynamic stress during operation and the resulting stress and fracture conditions on a cavern wall will be discussed. The results of the research project are used to explain the modified dimensioning approaches.
Energy in the form of gas, oil or petrol has been stored in salt caverns around the world for decades (Bays 1963, Thoms 2000). Some cavern structures already exist for storing renewable energies such as compressed air and hydrogen. The storage capacities of these media will be greatly expanded in the future and thus contribute to the global energy transition.
In Germany, the dimensioning of salt caverns is the responsibility of civil engineers specializing in geotechnical engineering. There is a strict mining law, and the approval authorities have high demands on the tightness and stability of the caverns. For this reason, dimensioning concepts have been developed by companies and universities in recent years, which differ in detail but all pursue the same goal: Safe storage of energy sources in salt caverns.
