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.