Interview: Susanne Hoecht, Images: Susanne Höcht
What was the aim of the project?
We aimed to contribute to the goals of the European Green Deal, which emphasizes marine energy as a crucial component of the future energy mix. By 2050, the EU aims to achieve approximately 40 gigawatt-hours of annual capacity from ocean energy installations. Among them, tidal energy is especially promising because it’s predictable and consistent. We believe that our project, “cableKites,” can play a small but meaningful role in reaching that vision.
Within the project, our goal was to develop and test a prototype that brings our concept to reality. The system consists of a continuous rope loop with several kites attached to it. As the water current acts on the kites, they pull the rope, keeping it moving around the pulleys. In this way, the kinetic energy of the water can be harvested and later converted into electrical energy using a generator. Through the prototype tests in the Isar Canal, we aimed to verify that this mechanical principle works in practice and to lay the foundation for further development toward offshore use.
How did you come up with the idea of using a rope drive to generate energy?
The concept originally came from our industrial partner, enrope GmbH. The founders, Anton and Peter Glasl, have extensive experience in building ski lifts. At some point, they wondered: what if we could reverse the idea? Instead of consuming energy to move the rope, as a ropeway normally does, could we also use the motion of the rope itself to generate energy? That reversed idea became the foundation of the cableKites concept.
How did you approach this project?
Our team brought together three main partners, each with a clear focus. Enrope took care of the mechanical design and built the prototype. Hochschule München focused on the development of kites, particularly in terms of hydrodynamics, design, and the behavior of kites in the water. Our Chair of Materials Handling, Material Flow, and Logistics at TUM examined the rope system itself, focusing on developing a calculation method for the rope line underwater and analyzing the applicability of existing cableway technology in marine use.
After working on this project for two years, the prototype was finally ready for testing. It was then installed in the Isar Canal with the support of Stadtwerke München, who provided the test site.
What was your role in the project?
My main role was to work on the rope system of the cableKites setup and to perform rope line calculations considering the impact of water mainly from hydrodynamic forces generated by kites.
In conventional ropeway systems, the rope is modeled as a two-dimensional problem, primarily influenced by gravity. But in our case, the rope is affected not only by gravity but also by lateral forces from the water flow. I extended the classical ropeway approach to a three-dimensional rope line calculation that also incorporates hydrodynamic effects from Kites.
How innovative is the system?
The cableKites system is quite unique because it transfers a well-known rope-way technology into a completely new environment. Traditional tidal energy systems usually rely on heavy turbines and fixed foundations. In contrast, cableKites uses a lightweight, modular setup with a circulating rope and kites that move with the water flow.
This ropeway-inspired approach enables the generation of energy even at low flow velocities, where turbines would no longer be efficient. It also offers advantages in terms of scalability, since the mechanical structure is simple and can be easily adapted or extended. In this sense, cableKites represents a new approach to harnessing marine energy, utilizing proven mechanical principles.
What were the results of the initial trials?
The prototype was successfully tested in the Isar Canal. The trials confirmed the mechanical functionality of the cableKites system. Although power generation has not yet been achieved, the experiment demonstrated its stable operational capability and confirmed the core design principles.
What further research is needed before the system can be implemented?
There is still a long way to go before it can be implemented. We will continually optimize the technology, including component design, to enhance energy conversion efficiency and develop solutions suitable for long-term marine environments. Simultaneously, developing a dynamic simulation model and control strategy for this system is crucial to ensure stability under varying flow conditions and achieve maximum power output.
Yujie Feng has been a research associate at the Chair of Materials Handling, Material Flow, Logistics since 2023. She completed her bachelor's degree in Shanghai and at Furtwangen University. She then studied Automotive Systems at the Technical University of Berlin.
More about the research project cableKites: https://www.mec.ed.tum.de/en/fml/research/2025/cablekites-reliable-climate-friendly-tidal-power-plant-with-ropeway-technology/
Video from Munich University of Applied Sciences on the tests in the Isar Canal: https://www.youtube.com/watch?v=rH-eA15NQcw