Another entry in high-flying kite-based wind technology has arrived and this one is being backed by a group of research institutes in Switzerland called the Swiss Kite Power Project which includes EMPA, the University of Applied Sciences Northwest Switzerland, the Federal Institute of Technology in Zurich (ETH Zurich) and the Federal Institute of Technology in Lausanne (EPFL).
The technology comes from start-up TwingTec and their Twing device (short for tethered wing), a lightweight and rigid kite, which is different than a lot of the airfoil sail-type kites already out there, made to be flown at least 100 meters above the reach of the tallest wind turbines.
EMPA says, "The principle is simple: the high-tech kite is fastened to lines attached to the reel in the ground station. The kite rises up to high altitudes with strong winds, which creates tension on the line setting the reel in motion. This movement is then converted into electrical energy by means of electromagnetic induction. Once the kite reaches its maximum height, the reel pulls it back down so it can rise again."
The flying out and then pulling back would be repeated every couple of minutes to keep the energy generation constant.
TwingTec was able to create a very rigid kite that is also lightweight by using Tensairity, a technology that was developed by EMPA that uses an over-pressurized air filled cylinder with a lightweight compression spine and cables for tension. This set up creates a very stiff beam that is the leading edge of the kite, with very little weight.
The start-up still has a few things to figure out, like how it will work around obstacles on land and the automation of the flights, but it has already received venture funding and is working on getting more.