Source: Energy & Management Powernews, November 10 2022
Researchers at KIT say there is huge potential area in Germany to store heat underground in groundwater. And the suitable area continues to grow.
In a study, researchers at the Institute for Applied Geosciences (AGW) and in the Sustainable Geoenergy Junior Research Group of the Karlsruhe Institute of Technology (KIT) have investigated which regions in Germany are suitable for near-surface low-temperature aquifer thermal energy storage (LT-ATES). The result: 54 percent of the area in Germany is very well or well suited for LT-ATES by 2050.
The potentials were mainly concentrated in the North German Basin, the Upper Rhine Graben, and the South German Molasse Basin, KIT said. They are visualized in detail on a map that the researchers created with a geographic information system (Gis) using a multi-criteria decision analysis, it said.
"The criteria for efficient LT-ATES operation include suitable hydrogeological conditions such as groundwater resource productivity and groundwater flow velocity," explained Ruben Stemmle, a member of the engineering geology research group at AGW and lead author of the study. A balanced relationship between heating and cooling energy requirements is also important. This can be determined approximately by the ratio of heating and cooling degree-days.
13 percent more by the year 2100
Accordingly, the researchers also assume that the areas very well or well suited for LT-ATES are expected to grow by 13 percent for the period 2071 to 2100. This, they say, is due to an increasing demand for cooling - caused by climate change.
Aquifers are naturally occurring, confined rock formations that carry groundwater at depths of up to several hundred meters. Water has a high ability to store thermal energy; the surrounding rock has an insulating effect. Aquifer reservoirs are tapped by drilling boreholes to store heat from solar thermal systems or waste heat from industrial plants, for example, underground and pump it up when needed. They can be combined with heat grids and heat pumps.
In water protection areas, aquifer storage is only permitted to a limited extent and in individual cases. 11 percent of the technically very well or well suited areas could therefore not be used, according to the researchers. "All in all, however, our study shows that Germany has great potential for seasonal heat and cold storage in aquifers," Stemmle says.
The results of the study have been published by Ruben Stemmle, Vanessa Hammer, Philipp Blum and Kathrin Menberg under the title "Potential of low-temperature aquifer thermal energy storage (LT-ATES) in Germany" in the journal Geothermal Energy. The text is freely available on the Internet.
Author: Katia Meyer-Tien
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