TUM researchers present assessment of Geothermal Energy Master Plan

Mathematically speaking, geothermal energy could meet 40 percent of Bavaria's heating needs

Southern Bavaria in particular has an enormous proven potential for deep geothermal energy. However, there are also reasons in which geothermal energy is not yet being used and where the potential has not yet been adequately investigated. Northern Bavaria is also home to as yet untapped deep-geothermal potential. The study's researchers indicate that establishment of deep geothermal energy sites in the regions where it has not been used up to now will more than anything require extensive further investigations. "In spite of the potential assumed on the basis of preliminary investigations, until now in northern Bavaria deep geothermal energy has only been utilized for thermal spas. This is why further exploratory measures such as test wells are necessary in order to determine the extent to which the northern part of Bavaria is suited for the use of deep geothermal energy. In southern Bavaria this also applies for example to Rosenheim and vicinity, where a high level of demand is found, but where geothermal energy as yet remains completely untapped," says Prof. Michael Drews of the TUM Professorship for Geothermal Technologies.

Geothermal energy is heat energy which is stored below the surface of the earth. The geothermal energy contained in the top ten kilometers of the earth's crust alone would be enough to cover today's level of energy demand for thousands of years. This makes geothermal energy one of the sustainable and green energy sources available to mankind. In order to exploit deep geothermal energy, hot thermal water is tapped with wells and then brought to the surface, where the heat can be transferred to a district heating system using for example heat exchangers.

The cooled water is then returned to the subsurface rock layers via injection wells. "There are two classifications of geothermal energy, near-surface and deep geothermal energy. While boreholes for near-surface geothermal energy are only a maximum of 400 meters deep, wells for deep geothermal energy can reach depths of up to 5,000 meters beneath the earth's surface. In southern Bavaria we have great potential for deep geothermal energy due to the particularly well-suited subsurface geological conditions," remarks Dr. Kai Zosseder of the TUM Professorship for Hydrogeology.

Deep geothermal energy is thus a sustainable alternative to district heating based on fossil fuel-fired heat and power plants and as such is an important component in the decarbonization of the state of Bavaria. 25 successful projects are already in use in southern Bavaria. Deep geothermal energy is already being used successfully today in the greater Munich metropolitan area and in the southeastern part of the state in particular. It currently covers approximately 0.5 percent of the total heat demand in Bavaria.