Generating Power From Kites

Researchers in Italy have high hopes for a new wind-power generator that resembles a backyard drying rack on steroids. Despite its appearance, the Kite Wind Generator, or KiteGen for short, could produce as much energy as a nuclear power plant.
Here's how it works: When wind hits the KiteGen, kites spring from funnels at the ends of poles. For each kite, winches release a pair of high-resistance cables to control direction and angle. The kites are not your Saturday-afternoon park variety but similar to those used for kite surfing -- light and ultra-resistant, capable of reaching an altitude of 2,000 meters.
KiteGen's core is set in motion by the twirl of the kites; the rotation activates large alternators producing current. A control system on autopilot optimizes the flight pattern to maximize the juice produced as it sails on night and day. A radar system can redirect kites within seconds in case of any interference: oncoming helicopters, for example. Or small planes or even single birds.
Research by Sequoia Automation, the small company near Turin heading the project, estimates that KiteGen could churn out one gigawatt of power at a cost of just 1.5 euros per megawatt hour. That's nearly 30 times less than the average cost in Europe of 43 euros per megawatt hour.
Proponents say other plusses of the merry-go-round generator are the contained cost of 360,000 euros and limited amount of space needed. Even with a modest diameter of about 320 feet (100 meters), they estimate KiteGen can produce half a gigawatt of energy. Emulators for the scalable project envision a 2,000 meter-version that would generate 5 gigawatts of power.
Fortunately for Sequoia, whose core business is sensor design and industrial automation, employees take work home with them. Massimo Ippolito, head of R&D, inspired by his weekend hobbies of hang gliding and kite surfing, started mulling the idea that would become KiteGen. Six years and seven patents later, he's leading a team of 20 to construct the giant, energy-creating carousel. The team expects it to be up and running in about two years.
"It's been called revolutionary, but I see it as part of a new energy future," said Ippolito, 48. "With the right mix of photovoltaic, solar thermal power, plus wind power from KiteGen, we can try to meet the needs for rising global electricity consumption."
Ippolito hopes that because of the amount of energy produced for its compact size, KiteGen will become the wind generator of choice, standing head and shoulders over similar recent projects such as glider generators and windmills.
So far, things look promising. A small-scale portable version called MobileGen (a single kite trailing from a flat-bed truck) made good headway when test-launched in August. It generated energy -- and a list of improvements. Researchers were "really charged up," Ippolito said, to see the generator in action.
It may not be completely smooth sailing for KiteGen, though. Some approve the concept but have adopted a wait-and-see attitude.
"It's a fascinating project, for the amount of power it promises and the low cost," said Luciano Pirazzi, who studies renewable energy for Italian government agency ENEA. "But -- and there are a series of buts -- it is still basically a concept on the drawing board. Feasibility has to be proven."
Outstanding questions about such a generator include location and possible bureaucratic headaches over permits for air space. Current speculation is that KiteGen may soar above the former Trino Vercellese nuclear power plant, already a no-fly zone, in the region.
Italy has until 2010 to bump up renewable energy to 22 percent of total electricity supply, in order to meet the EU Renewable Energy Directive. Wind power is a key component and competition from national and foreign enterprise is expected to be stiff.
Naysayers probably won't knock the wind entirely out of KiteGen's sails. Sequoia was honored earlier this year with a 2006 World Renewable Energy Award for its work on KiteGen.
KiteGen also managed to convince Turin utility company AEM to cover 40 percent of expenses for the prototype and sign on as technical partner. It was the first time the utility, which is a long way from Italy's prime windmill coastal zones, has invested in such a project.
"When you first see it you have to smile, because it's a bit funny looking," said Andrea Ponta, an engineer at AEM. "But the more you examine it, you see the idea is sound and the technology is already available."

http://www.wired.com/science/discoveries/news/2006/10/71908