Saturday, March 15, 2008

Innovative Low-Cost "Windbelt" Could Bring Wind Power to Developing World

These days, conventional thinking about wind turbines is "bigger is better." Since power output scales exponentially with rotor diameter, wind turbines are getting bigger and bigger in order to squeeze more clean energy out of the rushing wind. The Enercon E-126 is now the world's largest wind turbine. It's mammoth 126 meter (413 ft) rotor generates over 7 megawatts of electricity enough to power 1,775 average American homes.

Enter the tiny but innovative "windbelt."

Looking like some kind of pygmy David next to the towering Goliaths of modern, utility-scale wind turbines, the windbelt, an invention of 28-year-old Shawn Frayne, bucks any conventional thinking about wind turbine design. Instead, Frayne designed his invention to be low-cost, highly efficient, source of power at the milliwatt scale, not the megawatt scale.

Frayne invented the wind belt after working in Haiti and designed the tiny wind generator to produce enough, cheap power to run LED lights and radios in the homes of the world's poor.

Conventional, rotor-based wind turbines don't scale down well to such a tiny scale. There's too much friction in the gearbox and other components, which is why there are no rotor-based wind generators out there that put out under 50 watts, Frayne says. So he took a new tack, studying the way vibrations caused by the wind led to the collapse in 1940 of Washington's Tacoma Narrows Bridge (aka Galloping Gertie).

Frayne's windbelt, which won Popular Mechanic's 2007 Breakthrough award for innovative designs, consists of a taut membrane fitted with a pair of magnets that oscillate between metal coils to produce electricity.

According to Popular Mechanics:
Prototypes have generated 40 milliwatts in 10-mph slivers of wind, making his device 10 to 30 times as efficient as the best microturbines. Frayne envisions the Windbelt costing a few dollars and replacing kerosene lamps in Haitian homes. "Kerosene is smoky and it's a fire hazard," says Peter Haas, founder of the Appropriate Infrastructure Development Group, which helps people in developing countries to get environmentally sound access to clean water, sanitation and energy. "If Shawn's innovation breaks, locals can fix it. If a solar panel breaks, the family is out a panel."

Frayne hopes to help fund third-world distribution of his Windbelt with revenue from first-world applications. The windbelt could replace the batteries used to power temperature and humidity sensors in buildings, for example.

So here's to thinking big and designing small. We need innovative, clean energy solutions at all scales, and for deployment throughout the world, including the developing world. "There's not a huge amount of innovation being done for people making $2 to $4 per day," says Haas. "Shawn's work is definitely needed."

Frayne explains his invention at a video at Popular Mechanics.

[Image sources: Popular Mechanics. A hat tip to Tyler Burton at Breakthrough Blog]

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