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Electricity generated by wind power may raise temperatures and costs

And the wind turbines chop up birds. A new study from M.I.T. indicates that vast wind farms to generate electricity may raise local temperatures as much as 1degree Celsius (1.8 degrees F) on land, but have the opposite effect over water. That’s significant considering the IPCC was all exercised about a 0.6 degree Celsius temperature rise over the entire 20th Century.

Currently only about 2% of electricity in the U.S. is generated by wind power, but the Department of Energy estimates that as much as 20% of electricity could be generated by wind by 2030. (That estimate may be just wishful thinking.) To generate 20% of our electricity by wind power would require installation of millions of turbines across the U.S.

The M.I.T. researchers say that “using wind turbines to meet 10 percent of global energy demand in 2100 could cause temperatures to rise by one degree Celsius in the regions on land where the wind farms are installed, including a smaller increase in areas beyond those regions.” The researchers also suggest that the intermittency of wind power could require significant and costly backup options, such as natural gas-fired power plants.

Wind turbines disrupt air flow. The researchers say that the “temperature increase occurs because the wind turbines affect two processes that play critical roles in determining surface temperature and atmospheric circulation: vertical turbulent motion and horizontal heat transport. Turbulent motion refers to the process by which heat and moisture are transferred from the land or ocean surface to the lower atmosphere. Horizontal heat transport is the process by which steady large-scale winds transport excessive heat away from warm regions, generally in a horizontal direction, and redistribute it to cooler regions. This process is critical for large-scale heat redistribution, whereas the effects of turbulent motion are generally more localized.”

In the press release for the paper the researchers explain:
“In the analysis, the wind turbines on land reduced wind speed, particularly on the downwind side of the wind farms, which reduced the strength of the turbulent motion and horizontal heat transport processes that move heat away from the Earth’s surface. This resulted in less heat being transported to the upper parts of the atmosphere, as well as to other regions farther away from the wind farms. The effect is similar to being at the beach on a windy summer day: If the wind weakened or disappeared, it would get warmer.

In contrast, when examining ocean-based wind farms, Prinn and Wang found that wind turbines cooled the surface by more than one degree Celsius. They said that these results are unreliable, however, because in their analysis, they modeled the effects of wind turbines by introducing surface friction in the form of large artificial waves. But they acknowledge that this is not an accurate comparison, meaning that a better way of simulating marine-based wind turbines must be developed before reliable conclusions can be made.”

The researchers also said that large-scale wind farms would disrupt precipitation patterns, particularly at the mid-latitudes in the northern hemisphere.

Citation: Wang, C. and Prinn, R. G.: Potential climatic impacts and reliability of very large-scale wind farms, Atmos. Chem. Phys., 10, 2053-2061, 2010.

See full paper here: http://tinyurl.com/yz7sgt8

Another downside to wind turbines is their effect on wildlife, particularly birds of prey. An article in the London Telegraph notes that “The world’s largest and most carefully monitored wind farm, Altamont Pass in California, is estimated to have killed between 2,000 and 3,000 golden eagles alone in the past 20 years.” The article further notes that “Spain has one of the three highest concentrations of turbines in Europe and, according to the Spanish Ornithological Society, they may be killing up to a million birds a year.”

See the Telegraph article here: http://tinyurl.com/yjktby2

Finally, electricity generated from wind turbines is more expensive than fossil fuel or nuclear generation. The International Energy Agency (IEA) estimates that for commercial electricity generation plants that begin operations from 2015 to 2020, wind generation will cost $94 per megawatt hour capacity, versus $78 for gas, $69 for coal, and $72 for nuclear. (Source: IEA, 2009 World Energy Outlook). The U.S. Department of Energy’s Energy Information Administration estimates are higher. EIA estimates the cost of new generation will be $149 per megawatt hour capacity for wind, $83 for gas, $100 for coal, and $119 for nuclear. (Source: EIA, 2010 Energy Outlook).

by Jonathan DuHamel

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