Side holes are intended to increase heat output
July 21, 2026
Source: E & M powernews
As part of the current EU project “UPLIFT,” Fraunhofer IEG is further developing a drilling technique. The goal is to make existing geothermal wells more efficient and new projects easier to plan.
The project name “UPLIFT” stands for “Unlocking Petrothermal Lithologies through Innovative Fracture Technologies.” In this EU research project, which launched in May 2026, the Fraunhofer Institute for Energy Infrastructures and Geotechnologies (IEG)—with locations in Bochum and Cottbus, among other places—is further developing its Micro Turbine Drilling (MTD) technology for deep geothermal energy. The goal is to increase the yield of existing wells and reduce the costs and risks of new projects.
According to the Fraunhofer researchers, many geothermal projects fail to achieve the expected thermal output because they extract too little deep water. The MTD technique therefore operates directly within the existing wellbore: A micro-turbine is guided laterally into the rock at the desired depth, where it creates narrow lateral boreholes. These tap into additional aquifers and increase the contact area, allowing more hot water to be extracted.
“With MTD technology, we’re creating new opportunities to expand existing boreholes in a targeted manner,” says Niklas Geißler, group leader for micro-drilling technology at Fraunhofer IEG. The institute aims to use this technology to increase the chances of success for geothermal projects and reduce technical and economic risks.
Microturbine Operates Without a Drilling Rig
At the heart of the process is a drilling turbine less than five centimeters long and less than four centimeters wide. Water pressure from a flexible hose sets it in rotation. A guide mechanism directs the tool laterally from the existing borehole into the surrounding rock at the desired depth. There, a diamond-tipped drill head crushes the rock, while water flushes out the cuttings.
According to the Fraunhofer IEG, the turbine achieves a penetration rate of about one meter per hour, depending on the type of rock. Cameras, acoustic sensors, and backflow analyses monitor the process. The method does not require a conventional drilling rig. According to the researchers, it is therefore particularly well-suited for existing or reactivated boreholes.
The lateral boreholes created extend five to ten times deeper into the formation than a conventional perforation. The technology can be used in granite, basalt, sandstone, claystone, and limestone, among other rock types. The project aims to develop a prototype specifically tailored for geothermal applications.
Test in a 3,000-meter-deep borehole
Fraunhofer IEG plans to test the prototype at the Czech research center Research Infrastructure for Geothermal Energy (RINGEN) in Litomerice, about 50 kilometers northwest of Prague. A 3,000-meter-deep research well is available there. The system is to be equipped with several lateral branches. The partners will then investigate how the larger contact area affects the production capacity of the geothermal system.
In addition to drilling technology, Uplift encompasses further research activities. These include laboratory experiments at the BedrettoLab underground laboratory in Switzerland, improved digital models, and a real-time monitoring system for geothermal plants. The partners aim to use these measures to shorten development times and reduce the costs and risks of geothermal projects.
The GFZ Helmholtz Center for Geosciences in Potsdam is coordinating the project. The consortium includes partners from five countries, among them Charles University in Prague, Geo-Energie Suisse, ETH Zurich, and the European Federation of Geologists. Uplift will run through April 2030 and has a total budget of approximately 12.2 million euros. The European Union is funding the project with 10.9 million euros through the Horizon Europe program.
Author: Davina Spohn