Cheap Savonius Wind Turbine

[Surferbeetle]

From Wired

A group of volunteer engineers are finishing the design for a home-brewed wind turbine that will bring electricity to off-the-grid Guatemalan villages by this summer.

After the U.S. engineers finish the design, local workers in the town of Quetzaltenango will manufacture the small-scale turbine. It will produce 10-15 watts of electricity, enough to charge a 12-volt battery that can power simple devices like LED lights.

"They're replacing kerosene lamps, if anything at all," said Matt McLean, a mechanical engineer by day and leader of the wind-turbine project by night. "The biggest driver is just keeping the cost way down. We're shooting for under $100, which is a challenge, but we're in that range."

The effort comes amidst recent efforts to bring new light and power to small towns in the developing world. An estimated 1.6 billion people worldwide are without electricity, and many of them are forced to light their homes with kerosene. Using one of these lamps is like smoking two packs of cigarettes a day, says the World Bank, and the lamps present a significant fire risk. That's why many startup companies, such as d.Light, are trying to bring cheaper LED lights to homes, but they still need a solution for producing power locally.

And from wikipedia

Savonius wind turbines are a type of vertical-axis wind turbine (VAWT), used for converting the power of the wind into torque on a rotating shaft. They were invented by the Finnish engineer Sigurd J Savonius in 1922. Savonius turbines are one of the simplest turbines. Aerodynamically, they are drag-type devices, consisting of two or three scoops. Looking down on the rotor from above, a two-scoop machine would look like an "S" shape in cross section. Because of the curvature, the scoops experience less drag when moving against the wind than when moving with the wind. The differential drag causes the Savonius turbine to spin. Because they are drag-type devices, Savonius turbines extract much less of the wind's power than other similarly-sized lift-type turbines. Much of the swept area of a Savonius rotor is near the ground, making the overall energy extraction less effective due to lower wind speed at lower heights.

[120mm]

I think I will do this with my 17 year old daughter this summer as a project.

[Surferbeetle]

120mm,

Here is a kit that may be of interest. There are also plans out on the internet and Edmunds has some rare earth magnets that you will need. Keep them away from your electronics and watch your fingers though...

[Surferbeetle]

From the July 7th 2008 ENR

The U.S. is the second-largest wind-energy market and is posted to overtake Germany by the end of next year, according to the Brussels, Belgium-based Global Wind Energy Council

Engineering News Record notes in this article that the US had 15,616 installed MW of wind power in 2007.

A gigawatt equals a thousand megawatts (MW).

As reference points the EIA notes that Iraq had a 3.8 gigawatt capacity in a June 2008 update (#76 world ranking in this arena), Germany had a 120.4 gigawatt capacity in a June 2008 update (#6 world ranking in this arena) and that the US had a 956.7 gigawatt capacity in a June 2008 update (#1 world ranking in this arena).


From the July 7th 2008 Business Week

Wind power, while still just a speck in America's total energy mix, is no longer some fantasy of the Birkenstock set. In the U.S., more than 25,000 turbines produce 17 gigawatts of electricity-generating capacity, enough to power 4.5 million homes. Total capacity rose 45% last year and is forecast to nearly triple by 2012. Right now, only 1% of the country's electricity comes from wind, but government and industry leaders want to see that share hit 20% by 2030, both to boost the supply of carbon-free energy and to create green-collar jobs.

Such a transformation won't come easily. While much of America's wind energy is in the Midwest, demand for electricity is on the coasts. And the electrical grid, designed decades ago, can't move large quantities of electricity thousands of miles. There's plenty of wind off the coasts, but it's both expensive to harness and controversial; not-in-my-backyard sentiment has slowed some of the most high-profile projects

It costs roughly $225 million to build a 150-megawatt wind plant. Horizon, the big wind developer, has 11,000 megawatts of projects in the works...

Wikipedia has an interesting entry on electric power transmission

[goesh]

This is good stuff - lets not forget solar cooking boxes either , essentially a box lined with tin foil set in the sun - the literature says they really work. 3rd world women spend alot of time scrounging fire wood and alot of trees are taken down too. a couple hours away from scrounging fire wood = a bigger garden and more food for the family.

[J Wolfsberger]

This is pretty cool. It's also cheap enough they could build a series-parallel array and generate some respectable voltage and current.

Along those lines, here's a link for a scratch built solar power system: How To Build a Solar Generator