The thermal water reservoir in the Greater Munich area is already being utilised via around 50 boreholes with a total thermal output of approximately 400 MW. The additional potential that can be tapped is estimated at more than 1,000 MW and is now being precisely determined through the largest-ever seismic site survey in a highly populated urban area.
The new data can be used to identify potentially suitable sites for future geothermal projects, to further develop existing plants, and to coordinate the use of geothermal energy in the study area in the long term.
The GIGA-M project, funded by the Federal Ministry for Economic Affairs and Energy (BMWE), is a joint initiative involving the Technical University of Munich (co-ordinator), Stadtwerke München (head of the seismology team), Energie-Wende-Garching (seismology partner), the Ebersberg-Munich Energy Agency, the District of Munich and the City of Munich.
Modern seismic technology provides insight into the subsurface
“With GIGA-M, we are setting a new benchmark for seismic site exploration in urban areas. Large-scale 3D seismic surveys provide the data required to assess and systematically develop geothermal potential in the Greater Munich area. The experience gained can also provide important impetus for other cities and regions that want to develop deep geothermal energy as a component of their heat supply,” says Dr Maik Tiedemann, CEO of DMT GmbH & Co. KG and CEO of the TÜV NORD GROUP’s business unit Energy & Resources.
Specialised measurement vehicles known as ‘Vibro-Trucks’ are used for the measurements; these transmit controlled vibrations into the ground. The signals reflected off the various rock layers are recorded by thousands of geophones – highly sensitive ground sensors – and then analysed. The measurement data is used to create a high-resolution three-dimensional model of the subsurface, which provides information on geological structures and areas potentially suitable for deep geothermal energy.
Through the GIGA-M project in Munich, DMT is further expanding its role as one of the leading partners in the development of geothermal projects and the exploration of raw materials.
“A 3D seismic survey of this scale poses unique challenges in terms of planning and execution. In the densely populated survey area, a large number of measurement points, the deployment of vibro-trucks and the recording by thousands of geophones must be precisely co-ordinated. It is essential to generate a consistent data set across the entire survey area, from which the 3D model of the subsurface is subsequently created,” says Dr Christian Henke, Head of Seismic Exploration & Processing at DMT.
DMT has already carried out a large-scale 3D seismic survey in Münster to investigate the deep subsurface with a view to geothermal energy utilisation. The experience gained from planning and carrying out seismic surveys in urban areas is also being applied to the campaign in the Greater Munich area. Furthermore, DMT has many years’ experience in geophysical exploration and subsurface investigation for raw materials and energy projects worldwide.
