Our research aims to answer open questions in deep geothermal energy and to develop targeted solutions. The technology is considered holistically from exploration to the realized project and its optimized operation. Due to the interdisciplinary research approach of the GAB, opportunities as well as risks can be considered holistically from different perspectives.
Subproject: “Geological Exploration”
Based on research results from the previous GAB funding phases, alternative geothermal heat sources in northern Bavaria will be further investigated. The focus of the sub-project is on an assumend radiogenic granite body (“Haßberge granite”), which causes a positive heat anomaly in the subsurface. The energetic use of the granite could represent an important source of heat for the neighboring cities of Bamberg, Schweinfurt and Coburg in the future. The granite body will be characterized in terms of geometry, depth and structure within GAB 3.0 using various geophysical measurements. Particular emphasis is also placed on writing project proposals in order to be able to realize two gradient drillings and a 3D seismic survey with third-party funding. The overarching aim is to further develop the maturity of EGS technology in northern Bavaria so that a research well can be drilled into the granite body.
Subproject Manager: Dr. Wolfgang Bauer
Subproject: “Cross-Scale Reservoir Modeling”.
The aim of this sub-project is a better understanding of the Bavarian subsurface and its reservoir properties by modeling across scales. This aspect is particularly important as Bavaria’s geology is characterized by pronounced anisotropies, which would otherwise be lost when transferring laboratory results to field scale. The models will couple the thermal, hydraulic, mechanical and chemical effects. The selection of suitable boundary conditions under the respective aspects is also a central part of the work. Further aim of the sub-project is to elaborate development strategies beyond the Molasse Basin. Alternative Bavarian reservoirs include granites in northern Bavaria for EGS, as well as various sandstone formations across Bavaria for medium-depth reservoirs. New utilization concepts will be evaluated for improved use of the already established hydrothermal geothermal energy in the Molasse Basin. Especially the effects of lowered return flow temperatures on the reservoir and the densification of geothermal plants in the Munich area will be investigated.
Subproject Manager: Prof. Dr. Michael Drews and Dr. Kai Zosseder
Subproject: “Seismic Risk Minimization”
The focus of this subproject is on understanding and predicting seismicity that could be induced by geothermal projects, especially EGS. Three topics will be examined in detail:
- Causes and control options of induced seismicity;
- Possible effects of occurring seismicity and their countermeasures for buildings;
- Use of modern measurement systems for the areal estimation of the impact of occurring seismicity.
Since EGS projects are usually associated with a higher micro-earthquake rate, it is crucial to monitor seismicity accordingly and to take measures to prevent seismicity from causing damage. To this end, an adaptive tracking traffic light or, more broadly, an RMS is being developed. This method makes it possible to quantitatively investigate the stress conditions at the target depth. Possible effects of the occurring seismicity on the buildings directly influence public acceptance. In order to record them, new approaches to soil-structure interactions and the influence of soil properties are being researched. Finally, the area-wide seismic measurement system, known as “Distributed Acoustic Sensing” (DAS), is being investigated. This system, which is based on the use of unused fiber optic cables (“dark fiber”), will enable the accurate measurement of peak vibration velocities over large areas and support the determination of an impact area in the event of damage.
Subproject Manager: Dr. Joachim Wassermann
Subproject: “Plant Engineering and Flexible Operation”
The sub-project essentially focuses on four topics in the system technology of geothermal plants: feed pumps, large heat pumps, reversible ORC processes and cooling supply. The overarching goal is to develop technical approaches and methods that can be optimally applied to the geological conditions of the respective subsurface. The solutions are to be used directly in industry through cooperation. There is a need for research into monitoring the temperature and condition of the pump motor of submersible centrifugal pumps in order to detect thermal overloads and other faults at an early stage and thus minimize pump failures. For large heat pumps, new working media such as mixtures and natural refrigerants as well as heat transfer are to be investigated in order to ensure reliable and cost-efficient operation. The testing of innovative components and the optimization of system control in reversible ORC processes contribute to more flexible system operation. In addition, the technical solution of a hybrid absorption chiller is to be developed for the provision of cooling in order to make the plant technology sustainable.
Subproject Manager: Dr. Florian Heberle
Subproject: “System Optimization”
This sub-project focuses on the investigation of future fields of application and optimal system designs for geothermal energy. This primarily concerns the energy supply of industrial processes, the significant increase in the flexibility potential of geothermal energy with regard to sector coupling, the improved integration of geothermal energy in municipal heat planning, rounded off with detailed life cycle analyses of selected innovative technologies. The project investigates and optimizes technological approaches for supplying industrial customers with heat, steam and cooling. By focusing on increasing the temperature range of the technologies, the potential of medium-depth geothermal energy for industrial customers is evaluated and further increased. Against the background of the increasing demand for flexible technologies for sector coupling, this sub-project also investigates innovative approaches to increase the flexibility potential of geothermal energy. In particular, the future integration of heat storage and reversible ORC systems can significantly increase this potential compared to the current state of the art. In addition, the sub-project enables better integration of geothermal energy into municipal heat planning in the future. By combining detailed assessments of the potential of geothermal energy with general planning approaches for regional and urban energy planning, geothermal energy can be better integrated into municipal heat planning and implementation.
Subproject Manager: Christopher Schifflechner