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Non-Tech : Alternative energy -- Ignore unavailable to you. Want to Upgrade?

To: Doren who wrote (5566)	11/17/2008 8:30:10 PM
From: Condo	Read Replies (1) \| Respond to of 16955

One would think that geared transmission would help here. I'm thinking that if bicycles can shift automatically then why not windmills? Nice analogy, Doren. Just noticed the following article. These guys are projecting 50%+ power output from new and existing windmills.. New tech to the rescue? We'll see, maybe as soon as two months from now. Thursday, November 13, 2008 Better Wind Turbines A more efficient generator could convert more of the wind's energy into electricity. ExRo Technologies, a startup based in Vancouver, BC, has developed a new kind of generator that's well suited to harvesting energy from wind. It could lower the cost of wind turbines while increasing their power output by 50 percent. The new generator runs efficiently over a wider range of conditions than conventional generators do. When the shaft running through an ordinary generator is turning at the optimal rate, more than 90 percent of its energy can be converted into electricity. But if it speeds up or slows down, the generator's efficiency drops dramatically. This isn't a problem in conventional power plants, where the turbines turn at a steady rate, fed by a constant supply of energy from coal or some other fuel. But wind speed can vary wildly. Turbine blades that change pitch to catch more or less wind can help, as can transmissions that mediate between the spinning blades and the generator shaft. But transmissions add both manufacturing and maintenance costs, and there's a limit to how much changing the blade angle can compensate for changing winds. ExRo's new design replaces a mechanical transmission with what amounts to an electronic one. That increases the range of wind speeds at which it can operate efficiently and makes it more responsive to sudden gusts and lulls. While at the highest wind speeds the blades will still need to be pitched to shed wind, the generator will allow the turbine to capture more of the energy in high-speed winds and gusts. As a result, the turbine could produce 50 percent more power over the course of a year, says Jonathan Ritchey, ExRo's chief technology officer. Indeed, in some locations, the power output could double, says Ed Nowicki, a professor of electrical engineering at the University of Calgary, who has consulted to ExRo. (more...) technologyreview.com (wrap up:) ExRo has developed and tested a lab-scale prototype. Its estimates of increased power production come from models that use data from existing wind-turbine sites. By the end of this year or early next year, the company will begin field-testing a small, five-kilowatt wind turbine. Ritchey says that the company won't have firm figures for power production until those tests are complete. The next step will be to install larger, megawatt-scale generators in existing wind turbines.