New findings on wind farms
30 April 2012, 12:05
London - Large wind farms may have a warming effect on the local climate, research in the United States shows, casting a shadow over the long-term sustainability of wind power.
Carbon dioxide and other greenhouse gases from burning fossil fuels contribute to global warming, which could lead to the melting of glaciers, a rise in the sea level, ocean acidification, crop failure and other devastating effects, scientists say.
In a move to cut such emissions, many nations are moving towards cleaner energy sources such as wind power.
The world's wind farms last year had the capacity to produce 238 gigawatt of electricity at any one time - a 21% rise on 2010. Capacity is expected to reach nearly 500 gigawatt by the end of 2016 as more, and bigger, farms spring up, according to the Global Wind Energy Council.
Researchers at the State University of New York at Albany analysed the satellite data of areas around large wind farms in Texas, where four of the world's largest farms are located, over the period 2003 to 2011.
The results, published in the journal Nature Climate Change, showed a warming trend of up to 0.72ºC per decade in areas over the farms, compared with nearby regions without the farms.
"We attribute this warming primarily to wind farms," the study said.
The temperature change could be due to the effects of the energy expelled by farms and the movement and turbulence generated by turbine rotors, it said.
"These changes, if spatially large enough, may have noticeable impacts on local to regional weather and climate," the authors said.
But the researchers said more studies were needed, at different locations and for longer periods, before any firm conclusions could be drawn.
Scientists say the world's average temperature has warmed by about 0.8ºC since 1900, and nearly 0.2ºC per decade since 1979.
Efforts to cut carbon dioxide and other greenhouse gas emissions are not seen as sufficient to stop the planet heating up beyond 2ºC this century, a threshold scientists say risks an unstable climate in which weather extremes are common.
The Texas study found the temperature around wind farms rose more at night, compared with nearby regions.
This was possibly because while the earth usually cools after the sun sets, bringing the air temperature down and the turbulence produced by the farms keeping the ground in their area warm.