Deep geothermal energy
BGR is engaged in research and demonstration projects for deep geothermal energy development. Among others, BGR is working on geological and geophysical issues. Methods for extracting lithium from thermal waters are a further research topic.
Motivation
Since time immemorial, people have used the heat of the earth where high temperatures occur near the surface, for example for bathing or cooking. Regardless of the depth from which the geothermal energy is extracted, it can be used around the clock. This is a significant advantage over other renewable energy sources that are weather-dependent.
The underground temperature does not have to be high for geothermal energy use. In Germany and in many other countries, the shallow subsurface is increasingly used as a heat source to heat buildings. For this purpose, geothermal probes are drilled typically to depths of around 100 meters. The use of hot rocks and hot water from great depths (deep geothermal energy) is technically more complex, challenging and risky, but energetically more worthwhile than the heat use from the shallow subsurface.
BGR's activities
Within the framework of research projects, BGR contributes to the development of deep geothermal energy use in Germany and advises political institutions, energy suppliers and other interested parties with regard to geothermal utilization possibilities. The focus of BGR's investigations is currently on medium-depth geothermal energy resources with depths of up to approx. 2500 m, as geothermal projects are increasingly being implemented in Germany up to this depth. (Medium-depth geothermics is considered in the following as part of deep geothermics). Regionally, the North German Basin with its large untapped potential is a focal point of current activities.
BGR carries out geological, geophysical and geochemical investigations for potential uses of deep geothermal energy. The main data bases for this are drilling reports, borehole measurements and other investigations in connection with former oil and gas wells. Conceptual reservoir models are set up and simulations of thermal water flow and underground heat transport are carried out. In addition to heat extraction, heat storage in deep aquifers is also being investigated. Furthermore, technical aspects of the development and use of deep geothermal energy as well as new utilization concepts are considered and evaluated.
BGR has two of its own deep boreholes in the Hanover area, where the use of deep geothermal energy is being investigated as examples for the subsurface conditions in the North German Basin.
BGR's activities are not limited to Germany. BGR supports developing countries in the introduction and use of geothermal energy. For this, BGR's scientists are active in developing countries with favourable geothermal conditions. The focus of their specialists' work is on the geoscientific exploration and evaluation of geothermal resources.
Further information can be found here.
Current projects
Deep geothermics in Germany
The use of geothermal energy is becoming increasingly important both worldwide and in Germany. Large geothermal plants in Germany are mainly located in the Munich area, in the so-called South German Molasse Basin, where the deep subsurface has favourable rock permeabilites for the extraction of hot thermal water. Also, geothermal plants are operated in the Upper Rhine Graben and in the North German Basin extracting thermal waters from depths of around 2000 metres to 4000 metres. The large geothermal plants in Germany are used to supply local and district heating and in some cases also to generate electricity.
The availability of heat pumps for large thermal capacities (> 1 megawatt) has recently made it possible to use geothermal reservoirs with relatively low temperatures and depths (from approx. 40°C and 1000 m depth on). This development as well as advantageous cost and risk aspects are the main reasons for the increased attention being paid to medium-depth geothermal energy.
Lithium extraction from geothermal waters
Lithium is an essential raw material for the production of batteries, especially for electromobility and the storage of renewable energies. In some regions of Germany, especially in the Upper Rhine Graben and North German Basin, geothermal waters contain considerable quantities of dissolved lithium. Thus, the coupling of geothermal energy and raw material extraction is increasingly becoming a focus of research and industrial activities.
The combination of energy generation and raw material extraction could significantly improve the economic efficiency of geothermal plants and at the same time offer a domestic alternative to conventional lithium mining methods. Current research projects are investigating various sorption and extraction processes to efficiently extract lithium from the produced thermal waters without compromising geothermal energy production. BGR is pursuing this approach in cooperation with other research institutions and industrial partners in order to assess the potential of this technology for the German market.