Green Therma to evaluate feasibility of closed-loop geothermal in Kaiserslautern, Germany
Kaiserslautern, Germany (source: Stadtwerke Kaiserslautern)
Carlo Cariaga
4 Mar 2026
Green Therma will be evaluating the feasibility of deploying the Heat4Ever closed-loop geothermal solution for district heating in Kaiserslautern, Germany.
Green Therma has signed a Letter of Intent with Stadtwerke Kaiserslautern Versorgungs-AG (SWK) to evaluate the feasibility of deploying of their closed-loop geothermal solution for the district heating supply of Kaiserslautern, Germany. Should the results of the study be positive, the parties will discuss the next steps towards a potential multi-well geothermal project.
SWK first announced plans for geothermal district heating in March 2025, with the aim of harnessing a potential geothermal resource hosted by the Rotliegend sandstone layer at 2300 to 3300 meters depth. A seismic survey of the 151 km² Lutrina license area was then done later that year. The results from the seismic survey will provide a robust technical basis for the joint feasibility study, which will include the evaluation of geological and geophysical data, the assessment of potential drilling locations, and an initial analysis of the levelized cost of heat (LCOE).
A low-risk option for geothermal deployment
Green Therma’s proposed solution is based on their Heat4Ever technology, a closed loop system that is designed to significantly reduce exploration and production risks in geothermal. A core component of this is the DualVac technology, a deep geothermal single-well co-axial well design that uses continuous vacuum insulation to minimize heat loss. The technology was developed in collaboration with GFZ Potsdam as part of the European TRANSGEO initiative, which aims to explore how existing wells can be repurposed for geothermal heat extraction and storage.
The company is already working towards a full-scale deployment of the Heat4Ever technology in Aalborg, Denmark, with completion targeted by 2027. The DualVac technology will also be installed to depths of around 3000 meters at the district of Groß Schönebeck in Germany. This will be followed by a year-long test where the system will be measured, monitored, and challenged.
“ The energy transition requires scalable solutions with reduced geological risk and high operational predictability. Our Heat4Ever™ technology is designed precisely for this – it enables utilities to integrate geothermal heat with greater security ,” said Jørgen Peter Rasmussen, CEO of Green Therma.
SWK aims to harness geothermal energy for heating with the goal of reducing fuel imports and becoming independent of price fluctuations. Currently, 80% of the heating in Kaiserslautern comes from natural gas. As part of SWK’s goal of transitioning its heat supply to CO2-neutral sources by 2045, it aims to evaluate whether the Heat4Ever solution can supply geothermal heat to its 105-km district heating network.
“ SWK is determined to transform its heat supply towards climate neutrality while simultaneously ensuring a high level of supply security for our customers. The collaboration with Green Therma enables us to evaluate an innovative, closed-loop geothermal solution that can strengthen supply security and reduce the geological risk associated with using geothermal energy in our transformation process ,” said Dr. Arvid Blume, CEO of SWK Stadtwerke Kaiserslautern.
Source: Green Therma
