Friday, June 17, 2011

The Wind Boondoggle

I used to think that wind turbines could be a promising way of generating electricity, but lately I have been questioning this view. I read an analysis of windfarm output in Scotland over a 26-month period between November 2008 to December 2010. Some of the findings:

1. Average output from wind was 27.18% of metered capacity in 2009, 21.14% in 2010, and 24.08% between November 2008 and December 2010 inclusive. [This is less than the 30% of nameplate capacity that is usually predicted.]
2. There were 124 separate occasions from November 2008 till December 2010 when total generation from the windfarms metered by National Grid was less than 20MW. (Average capacity over the period was in excess of 1600MW).
3. The average frequency and duration of a low wind event of 20MW or less between November 2008 and December 2010 was once every 6.38 days for a period of 4.93 hours.
4. At each of the four highest peak demands of 2010 wind output was low being respectively 4.72%, 5.51%, 2.59% and 2.51% of capacity at peak demand.
Looking at a map of global mean wind speeds at hub height (80m), you can see that Scotland is as windy as the windiest parts of the United States. So the implications for wind power are not good if wind can't even make a useful contribution there.
In 2007, Jim Detmers, VP of the California ISO gave a talk at Stanford in which he said,
"Wind is not produced on peak. This last summer, when we went across the summer peak, I had 3,000 megawatts of capacity of wind. How much did I have on the summer peak, back in August? No, no, no, I didn't have zero. I had a total of 63 out of 3,000. And we're investing all of this money in wind..."
At this point, I'm more interested in thorium than wind. Even solar is rapidly becoming cheaper and more efficient. It will be hard for wind to surmount its liability of unpredictability and blowing at the wrong time.

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