Transition from hydrocarbon production to geothermal heat storage in the Upper Rhine Graben – the DeepStor project
The subsurface conditions of the Upper Rhine Graben are favorable for the development of novel geothermal utilization concepts. In particular, they allow optimization of energy use with flexible heat production and storage scenarios. A first potential analysis revealed an enormous storage potential of formerly used and well-explored oil fields. The involvement of former hydrocarbon reservoirs as components of geothermal concepts perfectly symbolizes the transition from the fossil-fuel age to the use of carbon-neutral renewable energies.
The proposed DeepStor concept takes advantage of these preconditions. The comprehensive geothermal concept is tailored to the Campus North of the Karlsruhe Institute of Technology (KIT) that is located in the central-eastern Upper Rhine Graben. It includes multi-level utilization with heat recovery from the deep Mesozoic reservoirs (associated GeoHeat project) and seasonal high-temperature heat storage in the Tertiary Sandstones above (DeepStor project). The KIT Campus North Campus offers good prerequisites for the concept implementation with extraction, seasonal storage and distribution of heat from deep geothermal energy: The underground of the campus is characterized by the largest known heat anomaly in Germany, with temperatures exceeding 100 °C at a depth of 2 km. An existing area-wide local heating network allows for heat distribution. In the long term, the concept provides for the coverage of a significant part of the basic heat load of the KIT Campus North in a climate-neutral way.
The scientific DeepStor storage project represents the first stage in the step-by-step development of deep geothermal energy utilization at the KIT Campus North. The targeted reservoirs involve the same Tertiary strata from which hydrocarbons have been extracted until the 1990s. Initially, the high-temperature thermal storage reservoir will be fed from cogeneration as well as current renewable waste heat from scientific infrastructures such as the biomass pilot facility "bioliq". The overarching scientific goal of the first DeepStor phase is the establishment of a scientific demonstrator to validate the technical feasibility of high-temperature heat storage in the deep underground. In the associated GECKO project, a transdisciplinary approach with natural and social sciences is pursued to develop concepts for deep geothermal energy usage on KIT Campus North in a co-design process with the local population.
Eva Schill1,2, Jens Grimmer1, Katharina Schätzler1, Kai Stricker1, Judith Bremer1, Thomas Kohl1