A new study by the Fraunhofer Institute for Energy Infrastructures and Geotechnologies (Fraunhofer IEG), Ruhr University Bochum, and the Technical University of Berlin aims to understand the dynamics of extracting geothermal fluids from limestone formations in the Rhine-Ruhr region in Germany. The R3CHAIN project runs from May 2026 to April 2029 and is funded by the Federal Ministry for Research, Technology and Space with approximately EUR 2.1 million.
Limestone formations in the Rhine-Ruhr region, such as the Devonian Massenkalk and the Carboniferous Kohlenkalk, have high hydraulic permeability due to karstification and fracturing. This makes them ideal formations to host geothermal fluids. However, geochemical processes can result in the dissolution of minerals along fracture and karst surfaces, possibly altering heat and flow properties. This can also have an adverse effect on subsurface and above-surface infrastructure.
The R3CHAIN project seeks to define subsurface processes and utilization concepts for the successful planning of geothermal projects using systems hosted by limestone formations. The program also includes the development of association digital tools. The following project milestones are planned:
- Compilation of geological and hydrogeological information in a structured database.
- Experimental analyses of the local rock in the Rhine-Ruhr region, especially with regard to interactions between rock and fluids.
- Derivation of a potential map for the Rhine-Ruhr region to identify suitable locations for deep geothermal energy.
- Extension of Fraunhofer’s own simulation software PyDoublet for calculating thermal power and heat content of fracture and karst conductors.
- Development of a deep geothermal module for the heat network software pandapipes .
An AI chatbot will then be developed that can access the project databases, maps, and simulation results and provide local analyses. This will help utility operator and network suppliers to independently assess the economic parameters of deep geothermal projects in the Rhine-Ruhr region.
Source: Fraunhofer IEG
