As an important contribution to the energy transition in Germany, not only electricity but also heat must be generated from renewable energies. Deep geothermal energy is a sustainable and efficient way to do this which has gained massively in importance in the light of the war in Ukraine, disrupted supply chains and climate goals.
And yet, according to the experts at DMT, its potential is not yet being sufficiently exploited. With their expertise and equipment, they want to play their part in bringing Germany’s heat supply up to a new level. DMT has proven in numerous projects that it can play an important role in everything from project planning and site exploration to plant engineering.
The convoy made up of DMT’s imposing vibrotrucks is 50 metres long as it rolls through the streets of night-time Duisburg. The 21-tonne special vehicles stop at regular short intervals and transmit sound waves into the ground. Highly sensitive measuring instruments known as geophones capture the reflections of these sound waves and collect important data concerning the composition of the subsurface.
Last October, DMT’s measuring teams spent 13 days and nights on the road taking measurements for the Geological Survey of North Rhine-Westphalia (GD NRW) and collected 15 terabytes of geodata over an almost 70 kilometre-long sampling route. “It would make sense to measure the potential for all the major cities in Germany,” says DMT Managing Director Dr. Maik Tiedemann, making a plea for nationwide action.
Germany has a great advantage in terms of deep geothermal energy – there are several areas where the geological conditions are ideal for such projects. These include parts of the Black Forest, Munich and large areas of southern Bavaria as well as regions around Berlin, in Lower Saxony and Brandenburg. Deep geothermal energy is based on the principle of using the heat generated deep below the ground: Water is pumped from great depths to the surface and, after the heat energy has been fed into the heating plant, returned to where it came from, where it warms up again.
DMT’s vibrotrucks would in principle be able to examine the subsoil of the 80 largest German cities within three years. This would cost 600 million euros and, according to Tiedemann, would be “manageable” compared to the total investment volume for the energy transition. There are practical reasons for concentrating on large cities: They are home to 26 million people, and the water, which warms up by up to 30 degrees Celsius per kilometre of depth, cannot be transported over long distances without energy losses.
Geophones are electromechanical converters which convert vibrations in the ground into analogue voltage signals.
They are used as small seismometers to find deposits in mining, to trace breaks in pressurised water pipes and, in building technology, to carry out subsoil investigations.
Prof. Bodo Lehmann, Head of the Geothermal Energy and Resources Unit at DMT, thus sees the greatest potential for deep geothermal energy as a contribution to the energy transition, especially in conurbations. After all, research institutes and experts such as the German Geothermal Association have made a bold statement: Deep geothermal energy could reliably meet at least 25% of the heat demand in Germany. “Large parts of Germany haven’t yet been explored. But we can assume that the actual potential is much greater still,” says Lehmann. However, the relatively new technology is still viewed with suspicion in some places.
DMT’s 3D seismology delivers 3D insights into the subsoil down to depths of several kilometres; this is essential when it comes to finding thermal water sources and carrying out targeted drilling.
Lehmann travelled with his team and the vibrotrucks to marketplaces in the Rhineland and answered a lot of questions about the technology and the processes. They found that local residents responded very positively to the stability and comparatively low costs promised by geothermal energy and recognized the benefits for those municipalities which would make a sustainable contribution to climate protection with their use of deep geothermal energy as well as strengthening their regions and making them independent. Lehmann is pleased that the potential of deep geothermal energy is now being recognized by policymakers and business and that the course is being set for its realisation.
At the federal state level, North Rhine-Westphalia Economics and Climate Protection Minister Mona Neubaur publicly supports the policy and participated in a DMT information event in Düsseldorf. And at the federal level, the coalition has included geothermal energy in the coalition agreement. In November 2022, the Ministry for Economic Affairs and Climate Action presented a “key issues paper for a geothermal energy transition”. This offers some convincing arguments for the widespread application of geothermal energy and sets the goal of connecting at least 100 new deep geothermal heating plants to the grid by 2030.
