Wind Farms: Nuisance or Need?
Apr 11, 2011
Wind farms are popping up all over farm country. Where once cattle were the only sight along rolling hills or desolate plains, windmills now speckle the sky line. Whether you find them to be a nuisance or a need, the fact is that they are beginning to overcome the farm country landscape. I recently read an article suggesting that wind farms don’t produce much energy as they are advertised to produce.
The article by Fast Company magazine
referenced a study from the John Muir Trust that they claim "debunks five important industry claims." I want to share that portion of the story with you and let you decide.
- Wind turbines will generate on average 30% of their rated capacity over a year. Using publicly-reported data from November 2008 to December 2010, the John Muir Trust analysis shows that the average output from wind in the U.K. was just 27.18% capacity in 2009, 21.14% of capacity in 2010, and 24.08% between November and December 2010.
- The wind is always blowing somewhere. Actually, it isn’t, at least if the report’s statistics are to be believed there were 124 times between November 2008 and December 2010 when total generation from wind farms feeding into the National Grid measured less than 20 MW. The capacity for these wind farms was over 1,600 MW. That’s for the entire country.
- Periods of widespread low wind are infrequent. Again, nope. The average frequency and duration of a "low wind event" (defined as an output of 20 MW or less) between November 2008 and December 2010 was once every 6.38 days for 4.93 hours at a time.
- The probability of very low wind output coinciding with peak electricity demand is slight. During the four highest peak electricity demand periods of 2010, wind output was never higher than 6% of total capacity. Not so helpful.
- Pumped storage hydro can fill the generation gap during prolonged low wind periods. If all four U.K. pumped storage hydro plants ran at the same time at full capacity, the stored water would run out in a day.
What do you think? Is wind energy worth the hassle and money it costs to put in wind farms?