The objectives of the InSpEE research project are the development and deployment of design principles and basic geological/geotechnical data and of site selection criteria for the establishment of salt caverns as well as the estimation of the renewable energy storage potentials of the salt structures in the North German Basin. Cooperating InSpEE project partners are the Federal Institute for Geosciences and Natural Resources (BGR), Leibniz University of Hanover, Institute of Geotechnical Engineering/Department of Underground Construction (IGtH) and KBB Underground Technologies GmbH (KBB UT) bringing in their expertise in the areas of salt geology and rock mechanics. Besides systematic collection and evaluation of geological information about salt deposits in North-West Germany thermo–mechanically based assessment criteria will be applied for the site characterization and estimate of its possible storage potential.
At the end of the three-year project period, a publicly accessible "Salt information system" will be provided and in addition, the storage potential for caverns as well as for hydrogen (H2) and compressed air (CAES) in Northern Germany shall be addressed. Within this paper the rock mechanical design for CAES and H2 storage in salt caverns under consideration of thermo-mechanical coupled calculations will be presented.
In Germany, there is consensus in government and industry that caverns in rock salt are going to be used in the future for the storage of renewable energies. The compressed air storage is available for short-term applications, while hydrogen storage plays a role more suitable for long-term applications. The goal of the currently ongoing research project is therefore to develop and provide design bases and geological basic data and criteria for site selection for the construction of salt caverns for the storage of hydrogen and compressed air. On this basis, estimation will be developed of the energy storage potential of Northern German salt structures for renewable energy. For a long time caverns in rock salt mainly were used to store crude oil and natural gas to offset seasonal fluctuations . In recent years, the requirements have changed, however, with the liberalization of the gas market. Modern trading storages require much more flexible storage options, which make particular by balancing short-term fluctuations in demand high requirements on the stress of the surrounding rock salt caverns. Transferability to different requirements of salt caverns for the storage of compressed air and hydrogen, however, is still open. The published operating experience of Europe's only cavern storage power plant in the Huntorf salt dome is not sufficient to quantitatively understand the interaction between rock salt and compressed air and to transfer lessons learned to other caverns with different boundary conditions.