German plains could someday harness the wind! Researchers are currently working on launching kites at low altitude to convert kinetic energy into electricity.

Kitesurfing has become a water sport traction fashion, with a growing number of enthusiasts who participate in this activity, a cross between a surfboard and a kite. Thus, when the wind blows in sailing, surfing achieves a jump several feet in the air.

According to the researchers, the modern kite is likely to become much more than just sports equipment and has the potential to become an energy producer machine. Aircraft movements of stunt kite can be used to drive a generator, which in turn can convert the kinetic energy into electricity.

The idea came from a Berlin-based company specializing in wind energy, NTS GmbH. To realize their concept, it uses the Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart. The project partners intend to use their new approach to harness the power of winds at altitudes up to 500 meters.

A “Central to kite”

“Kites flying at a height of 300 to 500 meters are perfectly positioned to catch the winds. With a length of 700 meters, the cables connecting the kites vehicles are responsible for towing them on rails. A generator will then convert the kinetic energy into electrical energy drawn vehicles. controls and measuring devices are positioned on the vehicle, “explained Joachim Montnacher engineer at IPA.

Compared to wind turbine technology that relies on turbines rotors, this technology offers a number of advantages. While the wind speed tends to zero at ground level, it increases significantly with altitude. At a height of 100 meters, the wind speed is 15 meters per second to 500 meters, over 20 meters per second.

“The energy efficiency of a kite far exceeds that of a wind turbine, whose rotor rotates at a maximum height of 200 meters. Doubling the wind speed is 8 times more to generate energy,” said J. Montnacher. “Depending on the wind conditions, 8 kites with a total area of 300 m2 is equivalent to 20 conventional wind turbines a power of 1 MW.”

More constant winds to 500 meters

The kites are not like conventional wind to worry about the constancy of the wind, because the higher one climbs, the more windy phenomena. The figures for the year show that at a height of 10 meters, there is only a 35% chance that winds reach 5 meters per second, but at 500 meters, this probability rises to 70%. This fact makes possible the production of wind energy in the plains. Another advantage is obviously the cost. This system is indeed much cheaper to build because it does not require heavy elements such as the nacelle and rotor, weighing hundreds of tons.

Flight maneuvers used to generate a high pulling power up to 10 kilonewtons (kN) – which means that a kite of 20 square meters has the ability to tow a tonne. Each vehicle is driven by a mechanism different flight with figures sinusoidal or eight-shaped.

On a test site based in Mecklenburg-Western Pomerania, the researchers were able to send two entities a kite for a maiden voyage along a linear track 400 meters long.

A remote control similar to that used to fly model aircraft was used to manually control the kite. Experts now want to reconfigure the test track in closed loop. Computers will eventually be used for fully automated control of kites.

“According to our simulations, we could use a track covering a total of 24 kites can produce 120 gigawatt-hours per year (4 GWh / year). In comparison, a 2-megawatt wind turbine produces about 4 GWh / year. Thus, one could replace NTS 30 wind turbines of 2 megawatts and power about 30,000 homes “said Guido Lutsch, CEO of NTS GmbH.

After successful test flights on the runway show, the project partners are optimistic about the validation of their computer modeling. Early investors are already on-board!

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