Flying wind power plants to generate energy at great heights

At high altitudes the wind is much stronger. Empa researchers want to harness the energy slumbering in the wind with the aid of kites. The technology would be particularly suitable for generating electricity in remote areas.

Rolf Luchsinger and his energy kite, which looks like a small sailplane

Anyone who has flown a kite at the seaside during a summer holiday is well aware of the power with which the wind tugs on it. Scientists working with Rolf Luchsinger at the Swiss Federal Laboratories for Materials Science and Technology (Empa), want to make use of this pulling power. They are developing energy kites that resemble small sailplanes.

Like drones, these flying wind turbines can take off and land automatically. After takeoff they spiral upwards using the force of the wind and pull the cable to which they are attached off of the cable drum. The axle of the cable drum is connected to a generator that produces electricity. When the cable is completely unwound, the kite automatically glides down again close to the launch platform and the cable rolls back onto the drum.

Autonomous take-off and landing

The big challenge is not the flying itself, Rolf Luchsinger explains. “The problem is the automated take-off and landing.” This was first achieved in the fall of 2018 using a prototype on the heights of the Chasseral mountain in western Switzerland. The energy kite with a wingspan of three meters took off from the base vehicle, climbed into the air, circled autonomously for 30 minutes, produced electrical energy, and finally landed safely again on the launch platform.

The next prototype, on which the team is currently working, should ensure continuous power generation. It will generate up to 10 kilowatts of electrical power and feed it into the electricity supply grid. BKW, an energy company based in the Swiss capital city of Berne, will be responsible for distributing the experimental wind-generated electricity. Empa has announced that the first series-produced model with a wingspan of 15 meters will then follow shortly after and will generate up to 100 kilowatts of power.

Energy kite replaces diesel generator

However, Rolf Luchsinger does not envisage the application of such flying wind power plants in densely populated areas, but rather in remote regions. “We are talking to mine operators, remote settlements, and islands as potential customers”, says the Empa researcher. “Currently these places still rely diesel generators that emit exhaust gases and generate noise, and whose fuel has to be delivered at great expense.”

Based on the idea of flying power plants, Rolf Luchsinger founded a spin-off in 2013 called TwingTec, one of the first companies to develop airborne wind energy plants. In Europe alone, ten start-ups and several teams from universities and technical colleges are currently developing solutions for this type of energy generation. At a conference in Glasgow in mid-October, they plan to exchange views on the latest developments.

Written by: sda

Photos: Empa

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