Google’s acquisition of Makani Power through the search giant’s Google[x] lab brought high-altitude wind to the fore in recent weeks, but as we mentioned at the time, Makani is hardly the only company looking skyward for strong and consistent wind power. And there’s yet another contender entering the picture: TwingTec, which is in the news after receiving backing from the Swiss funding forum Venture Kick.
Makani, you’ll recall, uses an airplane-like fixed-wing design with rather standard looking turbines on it to generate power in the sky and send it back to the ground. TwingTec is going a different route; the kites are part of a system that produces power back on the ground. In this sense, it’s more akin to the approach taken by SkySail (the company that you might remember for its wind-harnessing propulsion systems for cargo ships).
(There’s also a German plan to use kites for wind power, but in that case the kites pull vehicles on rails around a circuit. The kinetic energy of the moving vehicles is then converted by generator to electricity. In our humble opinion, that seems like too much space and machinery to be viable.)
The general idea in the SkySail and TwingTec cases is to send a kite into the air where strong winds can pull a cable from a reel to generate power. At maximum height, a smart ground station positions the kite to be pulled back with minimum force, and the process can be repeated, with a net energy gain each go-round.
Where TwingTec departs from SkySail and its paraglider-like kite is in developing a more sophisticated and it hopes more efficient kite. TwingTec is a spinoff of Empa, the Swiss research institute, and the TwingKite being developed is based on an Empa technology called “Tensairity.” As Empa explains it:
The structure is based on the ultra-lightweight Tensairity girder – a beam made of struts, tension elements, a membrane and air, with an enormous load-bearing capacity. This kite is being designed to ascend to altitudes of up to three hundred metres, withstand the very strong wind forces and may soon supply our houses with clean electricity from the windy heights.
The 300-meter max figure mentioned is interesting as it’s quite a bit lower than where Makani (250-600 meters) or SkySail (200-800 meters) do their thing. It’s also worth noting that while Makani and TwingTec seem to be focused on producing high-altitude power onshore, SkySail is strictly focused on offshore wind, offering a way to accesses deep water areas that aren’t available using traditional offshore wind platforms.
The TwingTec effort, playing out in a collaboration called SwissKitePower, got a 10,000 Swiss franc award from Venture Kick, the first step in a three-step process that could lead to 20,000 CHF for a business plan and then 100,000 CHF to fund startup.