Last week, we posted the results of a report from the John Muir Trust claiming that wind power is a lot more useless than the wind industry–or anyone invested in renewable energy, really–would like us to believe. Naturally, we were contacted by the American wind industry which wanted to aggressively refute the claims and spread the wind turbine gospel. Below, the epic battle between the John Muir Trust study and what the AWEA says is wrong with it (in our words, using information from our interview and their blog).
Wind turbines will generate on average 30% of their rated capacity over a year.
John Muir Trust: Wind turbines are inefficient. Using
publicly-reported data from November 2008 to December 2010, the average output from wind in the U.K.
was just 27.18% of capacity in 2009, 21.14% of capacity in 2010, and
24.08% between November 2008 and December 2010.
American Wind Energy Association (AWEA): Pay attention to the larger picture, John Muir Trust. Modern utility-scale wind turbines operate 65% to
90% of the time, but often run at less than full capacity (wind isn’t always that strong). So an average capacity of 25% to 40% is common–but this may change soon. The average capacity for wind turbines improves about 15% every two years.
Winner: John Muir Trust. Sure, turbines are improving, but John Muir didn’t say anything about the future in its report. A device that inefficient has problems.
The wind isn’t always blowing somewhere.
John Muir Trust: There
were 124 times between November 2008 and December 2010 when total
generation from wind farms feeding into the U.K. National Grid measured less
than 20 MW. The capacity for these wind farms was over 1,600 MW.
AWEA: Yes, it is. The U.K. is a tiny, fairly inconsequential island. That statement applies for areas much, much larger than the U.K.– areas like the one covered by the Midwest Independent System Operator (running throughout several states in the Midwest), which is five times the size of the U.K. In any case, fossil fuel and coal plants do fail sometimes, too. For example: In Feburary 2011, millions of Texans dealt with rolling blackouts because 50 fossil fuel-fired power plants all failed at the same time. Utility-scale wind turbines in the area kept spinning. How do you like them apples?
Winner: Draw. The AWEA is right if the future holds a utopian worldwide power grid where small countries can pump in glorious wind power from their neighbors. But in assessing the helpfulness of wind power to the U.K., it seems like it’s not the total answer.
Periods of widespread low wind are frequent.
John Muir Trust: The average frequency and duration of a “low wind event” in the U.K.(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.
AWEA: The U.K. experiences low wind events, then, during 3% of the time. That’s literally the definition of infrequent. In any case, grid operators can usually predict times of low wind–unlike, say, when a coal-fired power plant dies because of mechanical issues (or, ahem, when an earthquake knocks a nuclear plant offline). What are you complaining about?
Winner: AWEA. Coming with the math. Hard to argue with that.
The probability of very low wind output coinciding with peak electricity demand is acutally quite high.
John Muir Trust: During
the four highest peak electricity demand periods of of 2010, wind
output in the U.K. was never higher than 6% of total capacity.
AWEA: Fair enough. But in the U.S, wind farms generate between 10% and
40% of their rated capacity during times of peak electricity demand.
Winner: John Muir Trust. But again, we’re talking about wind for a tiny island, not at large.
Pumped storage hydro can’t fill the generation gap during prolonged low wind periods.
John Muir Trust: 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.
AWEA: That’s kind of a nonsensical argument. It’s wrong to assume that pumped storage hydro is the only tool that grid operators would have to supplement power during periods of low wind. Natural gas held in a pipeline, for example, could perform the same function.
Winner: AWEA. The problem of renewables storage is one that is conveniently swept under the rug, but once we tackle it, we’re assuming there will be better answers than just pumped hydro.
Overall Winner: It’s a tie! AWEA’s arguments make a lot of sense, but it’s arguing for wind power overall, not just in the U.K.. The final verdict won’t come until wind power provides much more of our energy. In 2008, the DOE estimated that wind power could provide 20% of all power in the U.S. by 2030. If that happens, it still will leave us screwed climate change-wise (assuming coal-fired plants make up much of the rest of that 80%). But it will at least settle, once and for all, the argument over wind power’s usefulness.
[Photo by Flick user Andertoons]