Wind turbines are extraordinarily unreliable because wind speeds are so inconsistent; the average output of a turbine is only about a quarter of its capacity (know as the 'load factor'). Also, due to the vagaries of the wind, the turbines are unpredictable.
One question to ask is—what if the wind slows down, or ceases to blow at all? One example—in January 2010, Britain's wind turbines supplied virtually no power on most days. (1)
In the US, according to Eric Worrall, we are experiencing the weakest wind speeds for 40 years and this is having a dramatic impact on the wind energy business. Electricity generated by US wind farms fell 6 percent in the first half of the year even as the nation expanded wind generation capacity by 9 percent. (2)
The reason was some of the softest air currents in 40 years, cutting power sales from wind farms to utilities. The feeble breezes come as the White House is promoting renewable energy, including wind, as part of its Clean Power Plan to counter greenhouse gas emissions.
One reader of Worrall's column noted: “If this becomes a trend, someone will blame it on CO2.” Well they were too late—this already had happened. Scientific American reported in 2009: “Three decades of data seemed to point to a future where global warming lowers wind speed enough to handicap the nascent wind industry.” (3)
Sara Pryor, professor and chair of the atmospheric science program at Indiana University, and colleagues, examined wind speed data from hundreds of locations across the US. They found that in most of the US, wind speeds appear to be waning, in many locations by more than 1 percent a year.
Mention was made that the situation may not be as dire as the data implied. Direct observations of wind speeds are inherently problematic. Anemometers are far less accurate and consistent than thermometers. In addition, almost all the locations used in the study were close to fast-growing urban areas that can alter wind patterns in unpredictable ways. And unlike temperature measurements, which in some location stretch back 150 years, relatively accurate widespread wind measurements began only in the 1970s—hardly enough time to pluck a subtle trend out of noisy data. (3)
Then, lo and behold, Pryor and colleagues two years later reported this:, “At least for the next 50 years, the wind resource in the regions of greatest wind energy penetration will not move beyond the historical envelope of variability. Thus, this work suggests that the wind energy industry can, and will, continue to make a contribution to electricity provision in these regions for at least the next several decades.” (4) So, in 2009, Pryor and colleagues said that wind will blow weaker, and two years later, maybe not. Clearly, as mentioned above, observations of wind speeds are problematic.
How much energy is wind providing worldwide? According to the BP Statistical Review of World Energy, wind and solar power provided, between them, just 1.35% of world energy in 2014, cutting emissions by even less than that. (5)
Eric Worrall concludes, “In my opinion this once again demonstrates how useless wind power is, as an energy solution for an economy which requires a reliable, biddable supply of electricity. It might one day be possible to create an affordable energy storage solution which can provide economical backup for the entire electricity grid for a few hours, or even a few days. But an energy storage solution which can hold enough energy to supplement the entire country's energy needs for months, or even years, on one charge, is utterly implausible.” (2)
References
Dennis T. Avery, “A chill hits wind power,” CFACT, February 1, 2010
Eric Worrall, “Renewable fail: weakest US winds for 40 years years,” wattsupwiththat.com, September 5, 2015
Michael Moyer, “Climate change may mean slower winds,” Scientific American, September 21, 2009
S. C. Pryor and R. J. Barthelmie, “Assessing climate change impacts on the near-term stability of the wind energy resource over the United States,” PNAS, 108, 8167, May 17,2011
Matt Ridley, “The recurrent problem of green scares that don't live up to the hype,” wattsupwiththat.com, August 17, 2015
Jack Dini is author of Challenging Environmental Mythology. He has also written for American Council on Science and Health, Environment & Climate News, and Hawaii Reporter.
