Geothermal battery project in Karlsruhe, Germany receives drilling permit

The geology of the planned DeepStor-1 exploration drilling project in Karlsruhe, Germany (source: KIT)

Carlo Cariaga 2 Dec 2025

The drilling permit has been granted for the DeepStor project which aims to investigate the viability of high-temperature heat storage in an underground “geothermal battery” in the Karlsruhe region in Germany. The exploratory borehole DeepStor-1 will be drilled at the Campus North premises of the Karlsruhe Institute of Technology (KIT).

Preparatory work on the drilling site is scheduled to begin in the coming months. Drilling of the exploratory borehole is then expected to start by Q2/Q3 2026.

First reported back in 2023, the DeepStor research project is exploring the possibility of storing excess thermal energy in the summer which can then be used for climate-friendly heating in the winter. Depleted oil formations, among other things, are deemed suitable for such “geothermal batteries”. There are several former oil formations in the Karlsruhe region and the wider Upper Rhine Graben, which means there is great storage potential in the region.

Thus, the DeepStor-1 well will be drilled into one of the potential storage locations on the edge of the former Leopolodshafen oil field in the Campus North. The well will be drilled to a depth of 1400 meters. A drill core will be extracted in one part of the borehole, and data from logging and testing will be collected. Processing and modeling of the data will help answer fundamental questions about the suitability of the subsurface for heat storage.

There will also be a seismic monitoring network in place connected to a traffic-light response system. Due to the sensitivity of the surrounding research infrastructure, conservative vibration thresholds have been established for DeepStor.

Source: KIT (1 and 2) and Thomas Bloch via LinkedIn