More than 200 years ago, Benjamin Franklin advanced the research of electricity by flying a kite. Now, a German company is taking a slightly different tack on that old idea by using kites to generate energy.
Nature Technology Systems (NTS) GbH has designed a principle based on the same elements of energy output, speed, and consistency used in wind turbines, according to the company. The result is a method that uses clusters of kites to form an aerial power station 1,000 feet to 2,000 feet in the air that produces energy on the ground.
The system, which NTS is testing in collaboration with the Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart, works like this:
The kites fly at high altitudes, where there are strong winds, on a tether of cables about 2,000 feet in length that's connected to vehicles on the ground, said Joachim Montnacher, an engineer at the IPA, in a press release. Those vehicles are pulled around a circuit on rails, producing kinetic energy that is then turned into electricity by a generator. The vehicles include the control and measuring mechanisms for the energy generated.
Specifically, the kites generate the energy through buoyancy achieved when a kite flies in high wind speed, according to NTS. Anyone who has ever flown a kite will know that the pull of the kite increases the faster the kite flies. NTS's design of the system allows the kite to surpass a buoyancy of about 110 lb/22 ft. "So when we fly a 20m2 (215 ft) sized kite it will be able to drag and lift up to 1 ton in weight," the company explained on its Website.
NTS insists its kite energy farms are more efficient, economical, and environmentally friendly than wind turbines. Because typical wind turbine rotors max out at a height of about 650 feet, they can't take advantage of winds at higher elevations, which are stronger. "Depending on wind conditions, eight kites with a combined surface area of up to 300 square meters (about 3,200 feet) can equate to 20 conventional 1 megawatt wind turbines, Montnacher said.
The kites also avoid material and financial investment in wind turbine infrastructure, which has more of an impact on the environment.
NTS will continue to test its kite system and will reveal its findings and seek feedback from the energy industry once these tests are complete, the company said.
The Germans aren't the only ones taking to the skies to find new and different ways to use wind and air currents to create alternative sources of energy. The US military recently tested a method to fly aircraft in formation that would promote fuel efficiency by using vortex surfing, a technique similar to what bicycle racers and migrating birds do when they cluster together to draft off each other.