Source: Energy & Management Powernews, June 23, 2022
Researchers are illuminating questions about reservoir technology and borehole safety of geothermal plants in the future directly underground. For this purpose, a new mine is being built.
Helmet on, headlamp on: The Karlsruhe Institute of Technology (KIT), the German Research Centre for Geosciences (GFZ) and the Helmholtz Centre for Environmental Research (UFZ) want to build a mine in the Black Forest or Odenwald. It will house a new type of laboratory. In the "Geothermal Laboratory in the Crystalline Basement", as it is called, scientists want to investigate questions on reservoir technology and borehole safety of geothermal plants, as KIT reports. The Helmholtz Association is funding the project with 35 million euros.
For their underground laboratory, the project partners want to dig a tunnel with a length of about one kilometer. The adit is to lead to caverns, and from there flow tests are to be carried out in the rock at flow rates relevant to geothermal energy. And this will be done under a rock layer of about 400 meters.
"Using state-of-the-art methods, we are able to record thermal, hydraulic, chemical and mechanical parameters. In this way, we will gain a fundamental understanding of geothermal transport processes and will also make a significant contribution to safety research for geothermal energy," says Oliver Kraft, vice president for research at KIT.
Measures against "induced seismicity"
The fact that geothermal energy has not been used much in this country so far is partly due to citizens' concerns about artificially induced earthquakes, explains the project's scientific coordinator, Thomas Kohl of the Institute for Applied Geosciences. "These occur primarily when fluids are improperly injected into a reservoir." In principle, however, he said, the application of such "enhanced geothermal systems" is necessary to make the great potential of geothermal energy economically viable, regardless of location, even in regions with crystalline bedrock.
Most of the time, however, the necessary flow rates in crystalline rock can only be achieved through appropriate "enhancement measures." "A crucial task of research in the new laboratory will therefore be to "improve the understanding of induced seismicity and experimentally demonstrate measures to prevent it," Kohl said.
The data from underground is not only intended to allay fears above ground. In addition to an open dialogue with citizens, rapid approval procedures are also needed, says GFZ researcher Susanne Buiter. Here, too, research at the mine will "make important contributions and enable a knowledge-based approach."
KIT President Holger Hanselka sees great potential for geothermal energy: "In Germany alone, we could use it to replace a third of the gas required for our heating," he explains. In view of the looming climate catastrophe and the geopolitical world situation, it is no longer possible to do without it.
Author: Manfred Fischer
