"Windspinners" (Score 2, Informative)

When I saw the photo, I immediately thought of my local library's copy of a hippy-era how-to on building a vertical-axis wind generator out of 55-gallon drums, plywood and junkyard auto parts like axle bearings and alternators. It's called "Wind and Windspinners: A Nuts and Bolts Approach to Wind-Electric Systems" by Michael Hackleman.

Basically, you cut the drum in half longways, and then offset the halves from each other to form an "S" shape with the two halves overlapping slightly, so that wind enters the open side, follows its contour into the closed side and exits out the back. The book recommended stacking 3 such drums, offset 60 degrees from each other and with plywood circles between the drums to prevent spilled wind. If you want to get fancy, you build sprung gates into the backs of the drums so they can dump excess wind in a storm. There are some drawings and photos of the design here.

I think Hackleman's reason for championing the Savonius design had nothing to do with efficiency - instead, it was all about cost, simplicity and durability. Fits right into the microgrid idea - a small village in the third world could assemble a few of the cheap homemade versions of these and link them to a battery bank to get themselves some simple, reliable electricity for whatever they needed to power.