A wind turbine designed like a kite is set to shake up the wind power sector. Are traditional wind turbines on their way out?
In most countries in the Global North, wind farms and their rows upon rows of large windmills are now a common sight - both on land and offshore. Although only accounting for around 3 percent of global electricity production, wind power has become an increasingly viable alternative power source around the world - including large scale expansion of wind power facilities in China and India.
However, it is within the EU heartlands that wind power is the most potent, especially in nations such as Scotland, Denmark and Germany. In the last country’s case, wind power now provides around 37.8 percent of electricity and is by far the largest source of renewable energy in the country's power mix. According to the Federal Environment Agency, onshore and offshore wind energy accounted for almost half of electricity generation from renewable energies, although an end to state subsidies and feed in tariffs, as well as ageing infrastructure, could slow this development in the coming years.
One startup, KiteKraft, is now trying to safeguard the future of wind power by revolutionising the system. Following years of study at the Technical University of Munich, they have taken the most effective part of a wind turbine - the rotor blades - and removed much of the other remaining structures. Most conventional wind turbines are so-called windward runners, i.e. they are designed to face the wind, with the wind hitting the rotor blades first and then the tower. The blade tips are the part of the turbine that receives the most energy, while the remainder serves mainly as a supporting structure and to provide the structure with the necessary height. In the KiteKraft model, they have replaced these elements with a flexible line and a small ground station. Floating at the end of the line is a specially designed ‘turnkey kite’ consisting of a single rigid wing that supports various wind turbines. The kite extends to its full length in windy conditions, and then performs figure eight movements to produce electricity and prevent the line from snagging.
Wind Turbine vs. Kite
The new technology has several advantages over a traditional wind turbine. Firstly, considerably less building material is required as the kite power plant consists only of the wing and a few other components. This reduces the ecological footprint during the construction of the power plant as well as making it more ideal for out of reach rural areas. Secondly, the height at which the kite flies is variable, meaning it can be modified to attain best results in different weather conditions. Additionally, the construction method allows the location to be changed quickly and easily, making the system flexible enough to accommodate short-term changes. Other, rather superficial criticisms of wind turbines, such as their affect on the landscape, are also largely omitted from the kites. No tower and no large wings are necessary and because the kite flies relatively high compared to its size, it is hardly visible from the ground.
The first prototype with a wing width of 2.4 meters and 5 kW power generation potential was presented in April 2019. It will serve as a platform for development and testing. In the long run, however, the kite should have a wingspan of up to 16 meters and generate 500 kW.
This isn’t the first time that innovative alternatives to wind turbines have been floated - literally in some cases. ETH Zurich is testing a so-called Airborne Wind Energy System and a German company Enerkite also wants to capture the energy from high winds with a prototype flying wind turbine.
This is a translation by Mark Newton of an original article which first appeared on RESET's German-language site.