Winkraft means not only clean energy, but also angry residents and conservationists, especially in Germany, who are warning about the potential consequences of the expansion for birds and bats. But the large, stationary wind turbines are not the only way to convert the power of the wind into electrical energy. Airborne Wind Energy (AWE) uses large flying objects at high altitudes to generate electricity.
High-altitude power generation
Some flying objects used in airborne wind power are reminiscent of kites, but others look like large airplanes with a pair of rotors. The generators, which then convert the mechanical movement into electrical energy, are located either directly in the flying object or in a ground station. In the journal “Annual Review of Control, Robotics and Autonomous SystemsAn ongoing study is addressing the challenges of the technology and its current status.
There are also companies in Germany that are investigating the possibilities of wind energy from the air. One of these is Kitecraft, a company from Munich. †Airborne wind power plants are cheaper to produce, easier to transport and more efficient. If you have all these advantages, why would anyone build a traditional wind turbine?”, says Florian Bauer, CTO of the company.
Better for the environment and more efficient
In theory, wind turbines in the air are superior to their traditional relatives on the ground. Modern wind turbines currently reach a maximum height of 250 meters. The average height in this country is only 130 meters. A wind power plant in the air, on the other hand, can climb up to 500 meters in height. High-altitude winds already prevail at this altitude, which are much more constant than the winds in the lower air layers.
Moreover, unlike wind turbines, airborne wind power plants do not restrict visibility and pose no major threat to birds or bats as most of these animals do not fly at such heights. In addition, the ground stations are smaller and construction is cheaper in terms of material costs. In remote areas, the technology could be a real alternative to classic wind turbines.
Challenges for the technology
Until now, however, these advantages only existed on paper. In reality, the technology is still in its infancy. Start-ups such as the already mentioned Munich company Kitekraft, but also Starsails Power from Hamburg are stimulating the development of aircraft power plants.
Like any technology, Airborne Wind Energy has drawbacks. The higher altitude poses a greater risk to air traffic, especially since a thin cable is much more easily overlooked than a wind turbine. Of course, because of the altitude, there is no danger to commercial aircraft, but small aircraft such as gliders are often at such heights.
In addition, higher demands are made on the material. The flying object must not crash and must be able to withstand storms and thunderstorms. In addition, the flying object should ideally move in big eights in the air. Under no circumstances should it move uncontrollably, therefore complex control mechanisms are necessary.
Alternative to wind turbines?
If these challenges can be overcome, there could be an alternative to classic wind turbines that could even exceed them in terms of performance.
Meanwhile, skeptics note that the technology is not yet fully developed or established. A 2021 U.S. Department of Energy report said AWE was “immature and unproven.”
At Google, for example, associated plans have already been suspended. The company Makani Power, a startup assigned to Google’s research division Google X, gave up the development of airborne wind turbines in 2020. The reason given at the time was that the road to profitability was considerably longer and involved more risk than was believed.