Tuesday, July 19, 2005

Umbra Fisk at Grist triumphantly parrots industry sales material

After Umbra Fisk at Grist Magazine had written in January about the wonders of industrial wind power, a reader wrote to ask about actual evidence of its positive impact. Yesterday, she replied "triumphantly."

With utter disregard for her claim of triumph, the reader has replied in the comments section:
The metaphor about unreliable babysitters is not quite accurate. Wind is indeed a "flaky" power source, in that only the wind determines when it contributes power. But as a "nondispatchable" source, it does not wait to be asked. This babysitter occasionally shows up at your door whether you need her or not. [And you still can't go out, because there's no way to know when she'll just leave again.] There are reports from western Denmark that 84% of the wind-generated power was in fact not able to be used and had to be dumped.

The metaphor also makes a wrong turn about reliability with age. The wind turbine cannot become more reliable, because it still generates power only when the wind blows. (And below the ideal speed of 25-30 mph the amount of power generated falls off exponentially -- so that about two-thirds of the time wind turbines produce much less than their already low average of around 25% capacity.) Like an abused mate, it is the grid operators who must go to great lengths to better predict the whims of the wind so they have some idea when and how much the turbines will be adding power.

It is also problematic that Umbra turns to the industry lobby group AWEA for her answers about wind's real contribution. For example, she says that the U.S.'s 6,740 MW of installed wind power capacity "is expected" to generate almost 18 billion kilowatt-hours in 2005. The basis for that estimate is only the theoretical 30% capacity factor that the AWEA insists on despite the actual record being significantly lower.

According to the Energy Information Agency, in 2002, wind and solar together generated only 0.17% of the electricity used in the U.S., less than 5 TW-h. Almost all of that is wind, so from the average installed capacity between the end of 2001 and the end of 2002 (according to the AWEA) of 4,480 MW that represents an output of only 12.7% of capacity.

The people of Lamar, Colorado, insist that the winds are not puny. Nobody has suggested otherwise. Nor are the turbines. It is the usable power produced by them that is puny. The apt metaphor is Aesop's trembling mountain that gives birth to a mouse. At the AWEA's imagined 30% capacity factor, the 12,000-acre 162-MW Lamar facility would produce the equivalent of 3% of Colorado's electricity use. Realistically, however, it may provide less than half of that. And it would produce at that low average rate or better only a third of the time, times that would only rarely correspond to actual need.
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