"When it first opened atop Buffalo Mountain with three turbines in 2001, the South's first commercial wind farm produced a mere 2 megawatts of electricity, enough for just 360 homes. But the December addition to the grid of 15 larger turbines -- each as tall as a 26-story building -- boosted the capacity to 29 megawatts, enough for 3,000 homes."If 2 MW represents the energy use of 360 homes, then 29 MW should represent the energy use of 5,220 homes. Or if 29 MW is equivalent to the energy needs of 3,000 homes, then 2 MW would be equivalent to the needs of 207 homes. One ought to question rather than mindlessly parrot such obviously confusing numbers.
(Forget for the moment that only a third of of electricity use is residential, and only a third of all energy use is for electricity, so even the undefined claim of "homes provided for" represents only a ninth part of the whole problem. Also forget that wind-generated production rarely coincides with demand, so that much of it isn't even used.)
Assuming 10 MW-h to be the amount of electricity used by a "home" in the U.S., 2 MW and 360 homes represents an output of 20.5% of capacity, and 29 MW and 3,000 homes only 11.8%. The Tennessee Valley Authority does not consistently report the production data from their Buffalo Mountain facility, but an analysis at Mens et Manus concludes that its average capacity factor is 21.9%.
(Despite such evidence from actual installations, the American Wind Energy Association still predicts a 30% capacity factor for on-shore wind turbines and even more for off-shore.)
Some or all of the figures in the Oak Ridger article may have been misreported (not only did they not notice the discrepant ratios, they also wrote produced where had a capacity of was meant. Household use in the area served by the TVA may be much more than the national average (and nearly doubled between the time of the original 2-MW project and the expansion to 29 MW). These are lame explanations.
Instead, because any deliberate fudging (the whole point of using the undefined unit of "homes") would have been to make their output appear greater, I suspect that the capacity factor of 11.8% might be near the true output.
In other news, Alan Chartock, in his "I, Publius" Berkshire Eagle column, predicts for 2005, "A hydroelectric windmill farm will be approved for the Berkshires." Now that's a confusion of terms.
Meanwhile in Wales, Liberal Democrat leader Mike German has written, "There is also a common misconception that wind energy is not available when wind is not blowing. Wind turbines operate by storing energy when the wind blows, not directly generating it to homes." He cites Friends of the Earth, Bheara, the British Wind Energy Association, and the Carbon Trust as the sources of his knowledge. It's incredible that a whole industry claiming to be essential to a viable future needs to lie so much.
