Energy Transition: Aquifer Storage Offers Great Potential

Researchers at KIT calculate that aquifer storage is a cost-efficient way to store energy
Diagram of geothermal heat exchange system showing seasonal groundwater flow and temperature changes. Ruben Stemmle, KIT
Aquifer storage is the most cost-effective thermal storage technology for cooling in summer (left) and heating in winter, for example.

About one-fifth of global greenhouse gas emissions are caused by heating and cooling. The demand for cooling in particular will rise sharply in the future. However, only a small portion of the energy required for this currently comes from renewable sources. Researchers at the Karlsruhe Institute of Technology (KIT) and partners have now conducted a study to investigate the economic viability of aquifer storage. In this process, cold or warm water is stored in natural groundwater reservoirs and extracted when the corresponding temperature energy is needed.

Storing energy underground

For their study, the scientists analyzed data from 132 facilities and compared it with the investment costs for other thermal energy storage systems and geothermal systems, such as geothermal probes.

“We were able to demonstrate that aquifer storage is the most cost-efficient thermal storage technology and should therefore be the preferred option in suitable hydrogeological conditions,” says Professor Philipp Blum from the Institute of Applied Geosciences at KIT, one of the initiators of the study. “However, many countries, including Germany, have hardly used aquifer storage to date. There is considerable potential for expansion here.” He advises integrating seasonal geothermal energy storage systems into municipal heating strategies. “Over 50 percent of Germany’s land area is suitable for this. The potential of this storage technology is therefore tremendous,” Blum says .

csa/mhe, September 12, 2025