March 21, 2005

The future in wind resistance

I must comment on a couple of recent pieces about industrial wind power, one by Doug Hufnagel of Maine and one by the editorial staff of the Boston Globe.

While the writer's heart is in the right place, he exaggerates wind power's potential contribution towards more sustainable energy use. The 11,000 wind turbines of Altamont and Tehachapi in California produce only 1% of the state's electricity use. At that rate, Maine would need almost 38,000 turbines to produce the amount of electricity people in the state use (not just in their homes). Most of the California turbines are smaller than the ones now proposed, but new ones require the same space, 30-60 acres per megawatt. At a capacity factor of 20%-25% (the record of facilities in similar areas), Maine's electricity use would require 132,000-330,000 acres of wind plant, 100-260 square miles.

But the wind doesn't blow at a constant rate, much less in response to actual demand for electricity. In fact, the wind turbines would produce at or above their average level only one third of the time. So Maine will have turned hundreds of square miles over to industrial development and still need the old sources of electricity most of the time.

The Boston Globe editorial not only exaggerates Cape Wind's possible contribution but also downplays the significant impact so many giant turbines, along with the necessary substations and cables, would obviously have. I just want to address the uncritically repeated claim from the developer that the project will provide 3/4 of the electricity used by Cape Cod and the Islands. First, that represents a 40% capacity factor, which is quite exaggerated -- it should be 20%-30% (in theory, off-shore wind is more steady, but 20%-30% is the record of existing facilities), so the figure should be revised to less than half. But, as above, average or more output of a wind plant is seen only one third of the time. Most of the time, the Cape Wind facility will not be providing much electricity at all, making a mockery of the huge investment and desecration of the seascape.

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