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The current energy demand of our society is high and the use the geological subsurface is manifold. The usage includes beside the optimum exploitation of oil and gas reservoirs shale gas or unconventional gas extraction, carbon capture and storage (CCS), H2 storage and the extraction of heat by geothermal systems (hot-dry rock or engineered geothermal systems; EGS). Classically, we use the subsurface also for mining activities interestingly in some areas reactivated through the high demand of strategic metals. Furthermore, our society is producing waste that has to be securely isolated from the biosphere due to its high chemotoxicity and/or radiotoxicity. For the later, there is a general international consensus that high-level heat generating radioactive waste (e.g. spent fuel from nuclear power plants) will be disposed in deep geological formations using of a multi-barrier system. This talk discusses the general concept of waste isolation in different geological formations (crystalline host rock, clay formations and rock salt), the transport processes and the challenges currently facing Germany, Europe and also India will be tackled. Towards the end of this presentation possible new waste forms produced by the energy transition and their possible reduction will be mentioned. |