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The Airborne Wind Energy Group

Airborne Wind Energy (AWE) Systems harvest wind energy by exploiting the aerodynamic forces generated by autonomous tethered wings, flying fast in crosswind conditions. This technology is able to reach higher altitudes than conventional wind turbines, where the wind is generally stronger and more consistent, while at the same time reducing the construction and installation costs of the generator.

In this research a ground-based generator concept is followed, whereby a kite is flown at high altitudes and the mechanical power is transmitted through tethers to a generator on the ground. To avoid tangling of tethers, the kite is typically flown on figure-eight trajectories.

Small scale prototype with a tethered surf kite flying autonomous crosswind paths.

Power is generated by the kite in two-phase cycles, so-called power cycles. During the first phase, the traction phase, the kite is driving the generators flying fast on crosswind paths maximizing the power. During this operation the lines are continuously unrolled until a maximum tether length is reached. This is followed by a so-called retraction phase where the kite is driven to the borders of the wind window and pulled back using less power than previously generated. The video below demonstrates the concept for a surf kite.

Surf kite flying autonomous power cycles.

To address the multidisciplinary nature of this work, we collaborate with different research centers (Empa, FHNW, EPFL) and the start-up TwingTec AG to develop fully-autonomous airborne wind energy platforms.

This research is supported by:




In collaboration with:

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Contact: Airborne Wind Energy Group
Automatic Control Laboratory
Physikstrasse 3
CH-8092 Zürich