Last week, Mr. On Pasture got stuck two days in a row behind a flatbed carrying a single blade of a wind turbine. The blade, standing upright, would be taller than the peak of our roof, he explained over supper. We can’t all afford such large scale wind power, but the good news is that it can happen on a much more human scale. In fact, thanks to a SARE project, Eric Andrus of Ferrisburg, Vermont created a design for a wind turbine that can be built for less than $1000 in materials.
The key to this low cost, low-tech turbine is the Savonius rotor, a design from Finnish inventor Sigurd Savonius in 1922. Imagine taking a pint of ice-cream, slicing it vertically down the middle, and then offsetting the two halves. That gives you the “vertical” way to capture wind.
Eric worked with Amos Baehr to build two versions of the wind turbine. The Mark I, was made out of wood. The Mark II was made out of metal. They used discarded 275-gallon fuel tanks for the rotors. You can see a comparison of the cost and output of the two different versions to help you think about which kid you might like to build:
It’s been a few years since construction, and Erik’s really satisfied with his turbine. On the whole, it is incredibly durable and captures the wind when it’s there. The issue for his location is that there’s not always that much wind. Still, with the 11 mph average windspeed at Boundbrook Farm, the turbine produces 1750 kWh per year. In about two years, Erik has calculated that he will have recouped the cost of construction of the Mark II turbine.
Rather than turning wind energy into electricity, the turbine Erik built captures wind energy to grind grain into flour which he and his wife use to bake bread at their Good Companion Bakery. Other on farm uses for the direct-drive power of their rotor might include:
• irrigation and drainage pumps
• stone-burr grain mills
• vacuum pumps for maple syrup operations
• ice cream makers or cream separators
• stationary woodworking equipment or small lumber mills
• square bale conveyors
• cement mixers
• feed mixing units
• wood splitters
• cordwood saws
• two-stage air compressors
If you’d like to learn more about the project and see the plans for building your own turbine, click here. It’s an interesting read as Erik describes their thought processes, takes you through their design process, and provides suggestions for how to make the project successful.
Editor’s Note: This isn’t the only way that Erik works with the wind. He is also the force behind the Vermont Sail Freight Project, which uses a sailing barge to transport products from Vermont farms to customers along the Hudson River and in NYC. As he puts it, “when we look to the power of wind, we should consider direct applications of power, rather than converting it to electricity.” Thanks to his projects, maybe we can do that more.
