ZIM-Cooperation project EWS.MWCNT

Development of highly efficient geothermal probes using nanotechnology

Aim of the “EWS.MWCNT” project is the development of geothermal probes with improved heat conduction through the use of nanomaterials and to significantly increase the efficiency and sustainability of near-surface geothermal energy.

In recent years, shallow geothermal energy has gained increasing importance in the context of sustainable and climate-friendly energy systems for the heating and cooling of buildings and districts, by utilizing the potential of geothermal energy from the upper layers of the earth (up to 200 m). To make these systems more efficient and thus even more sustainable, it is necessary to optimize the thermal conductivity of the various components.

In the research project "EWS.MWCNT", the network partners SKZ, Gerodur MPM Kunststoffverarbeitung GmbH & Co. KG, Friedrich-Alexander-University Erlangen-Nuremberg, and Laus GmbH are collaborating on the development of a highly efficient geothermal system based on conventional PE100-RC pipes and nanomaterials. This potential for improving thermal conductivity was already investigated in the ZIM feasibility study RiNuNano, on which the current project is based. This study yielded extremely promising results regarding performance enhancement, achieving an impressive increase in thermal conductivity of almost three times.

Practical tests for validation and further development

To enable simple, cost-effective, and practical performance determination of geothermal probes, a novel testing method is being developed within the framework of this collaborative project, which for the first time also allows for comparative analyses. The test rig will also be used to examine the performance of the developed probe pipes and to optimize their further development.

“We not only want to increase efficiency, but also to increase the acceptance of new materials through transparent testing methods. This is a decisive step for the market penetration of innovative geothermal technologies,” says Felix Berthold, project manager at the SKZ Plastics Center.

Increased security through the SSbD approach

A key aspect of geothermal probe development, especially with nanomaterials, is product safety. Therefore, an important component of the planned developments is the consideration of ecotoxicological aspects and potential release scenarios, as well as the assessment of impacts on the living environment.

In accordance with the European Commission's 'Safe and Sustainable by Design' (SSbD) framework, the production of materials and chemicals should be guided towards a sustainable industrial transformation through the steering of the innovation process. This aims to minimize the impacts on health, climate, and the environment throughout the entire life cycle of chemicals, materials, and products – from procurement and production to use and end-of-life.

In the project, universally applicable test methods will be developed and then consistently applied for ecotoxicological assessment. This includes investigating whether (and if so, to what extent) nanomaterials are released from the products and what safety measures may be necessary for their use in near-surface geothermal energy. The findings on acute and chronic toxicity, as well as the release scenarios of nanomaterials from nanocomposites, are directly incorporated into pipe development, ensuring that the final product is not only effective but also safe.

Greater efficiency, lower costs

This development will reduce the drilling depth and the total amount of material required for the probes by up to 20 percent. Despite higher material costs for the probes, the total costs will be reduced due to lower drilling costs and lower resource consumption. This will make geothermal energy more economically attractive and, at the same time, more environmentally sustainable. “With this project, we are laying the foundation for more efficient and cost-effective geothermal energy systems and making an important contribution to decarbonization and the achievement of climate targets in Germany,” says Berthold.

The reduced drilling depth also opens up new applications in regions that were previously considered unsuitable for geological reasons. This facilitates a broader use of geothermal energy and strengthens its contribution as a reliable renewable energy source.

This project is funded by the Federal Ministry for Economic Affairs and Energy (BMWE) as part of the Central Innovation Program for SMEs (ZIM) with the funding code 16KN102921 from December 1, 2024, to May 31, 2027.