The SKZ Plastics Center is implementing the EWS.MWCNT research project, which aims to develop highly efficient geothermal probes using nanotechnology. The key task is to create a geothermal system based on PE100-RC polyethylene pipes modified with multi-walled carbon nanotubes. The addition of multiwalled carbon nanotubes (MWCNT) is intended to significantly increase the thermal conductivity of the material while maintaining compliance with applicable standards and safety requirements. The improved thermal conductivity of the pipe material is expected to directly translate into higher efficiency in extracting heat from near-surface geothermal sources, reduced raw material consumption and better economic indicators for installations. The project is being carried out within the NanoGeoTherm network of the Nanoinitiative Bayern GmbH cluster in cooperation with Gerodur MPM Kunststoffverarbeitung, Friedrich-Alexander University Erlangen-Nuremberg and Laus. In addition to material and process issues, strong emphasis is placed on developing a simplified method for testing thermal conductivity and on a comprehensive assessment of the environmental compatibility and ecotoxicity of the new material. The project team highlights the importance of transparent test procedures for building market acceptance of innovative solutions for geothermal probes.
Objectives of the EWS.MWCNT project and scope of cooperation
The EWS.MWCNT project is being implemented within the NanoGeoTherm network, which operates in the Nanoinitiative Bayern GmbH cluster. SKZ is working with partners Gerodur MPM Kunststoffverarbeitung GmbH & Co. KG, Friedrich-Alexander University Erlangen-Nuremberg and Laus GmbH. Their common goal is to develop a highly efficient geothermal system based on plastics modified with multi-walled carbon nanotubes for the production of PE100-RC pipes with significantly increased thermal conductivity.
The scope of the project covers both the development of a suitable manufacturing process for PE-CNT pipes and the preparation of methodologies for testing the thermal properties and environmental aspects of the new material. An important premise is full compliance with relevant technical standards and safety requirements for components of geothermal installations.
Development of the manufacturing process and test methodology
One of the main tasks of the project is to develop a processing technology that enables uniform dispersion of carbon nanotubes in the PE100-RC polyethylene matrix and stable achievement of the required thermal conductivity properties. In parallel, the team is working on a simplified test procedure for determining the thermal conductivity of the pipe material.
The new method is intended to allow faster and less complex assessment of thermal parameters, which is important both in the material development phase and in quality control in future production. The measurement procedure under development is being supplemented by studies on environmental compatibility and ecotoxicity, including assessment of the potential impact of the nanofiller on the environment.
"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," emphasizes Felix Berthold, project manager at the SKZ Plastics Center.
Probe efficiency and impact on installation costs
According to the project assumptions, the increased thermal conductivity of PE-CNT pipes is expected to result in a reduction of drilling depth and the total amount of material required for geothermal probes by up to 20 percent. Despite higher material costs for the PE-CNT pipes themselves, the overall system costs are expected to be lower due to reduced drilling costs and lower resource consumption.
The economic attractiveness of near-surface geothermal energy is expected to improve thanks to a more favorable ratio of investment expenditure to resulting thermal output. At the same time, lower consumption of raw materials and energy related to drilling activities supports sustainability targets. "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.
New application opportunities through reduced drilling depth
The reduction in required drilling depth opens new possibilities for locating geothermal installations in regions that have so far been considered less suitable for geological reasons. Shorter probes and less intensive ground interventions can facilitate planning and permitting, as well as reduce technical and economic barriers for investors.
In this context, broader use of geothermal energy as a stable renewable energy source is of systemic importance. Improving the material characteristics of pipes, and thus of geothermal probes, can help increase the share of ground-source heat pump technologies in the energy mix, especially in urban areas and in modernized heating systems.
The “EWS.MWCNT” research project is developing PE-CNT pipes with improved thermal conductivity. (Photo: SKZ)
Toxicological assessment and potential further applications
To ensure safe use, the new pipes are subjected to toxicological evaluation from the outset of the project. The potential impacts of the nanocomposite on human health and the environment are analyzed over the entire product life cycle. In the longer term, positive results of such studies could enable the use of the developed material in other areas, including drinking water supply systems.
The toxicity assessment methodology being developed as part of the project is intended to be transferable to other nanocomposites, which in general terms may increase the safety level of modern nanomaterials in various industrial applications. In addition, the ability to purposefully adjust the thermal conductivity of the material provides a basis for designing geothermal probes tailored to local geological conditions and specific installation requirements.
This approach is intended to enable better optimization of geothermal systems in terms of energy efficiency and operational durability. Flexibility in selecting the parameters of the plastic material, while maintaining stringent safety requirements, may become an important element in the further development of near-surface geothermal technology.
Project funding and timeframe
The EWS.MWCNT project is funded by the German Federal Ministry for Economic Affairs and Energy (BMWi) under the Central Innovation Program for SMEs (ZIM). It has received funding under code 16KN102921 for the period from 1 December 2024 to 31 May 2027. This support enables the implementation of a comprehensive R&D program covering development of the material and processing technology as well as methods for assessing the thermal properties and environmental safety of the new solution.
The project results are expected to contribute to the development of more efficient and sustainable geothermal systems, supporting the achievement of energy transition objectives and the reduction of greenhouse gas emissions.
