Power India found that according to a study done by the researches at University of Albany in affiliation with USA Research Associations the large scale wind farms can increase the surface temperature by around 0.72 °C per decade.
The wind industry in the United States has experienced a remarkably rapid expansion of capacity in recent years and this fast growth is expected to continue in the future. While converting wind’s kinetic energy into electricity, wind turbines modify surface–atmosphere exchanges and the transfer of energy, momentum, mass and moisture within the atmosphere.
These changes, if spatially large enough, may have noticeable impacts on local to regional weather and climate.
The report has presented observational evidence for such impacts based on analyses of satellite data for the period of 2003–2011 over a region in west-central Texas, where four of the world’s largest wind farms are located.
The results show a significant warming trend of up to 0.72 °C per decade, particularly at night-time, over wind farms relative to nearby non-wind-farm regions. This can be attributed to wind farms as its spatial pattern and magnitude couples very well with the geographic distribution of wind turbines.
MORE RESEARCH NEEDED
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 0.8 degrees Celsius since 1900, and nearly 0.2 degrees 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 2 degrees C 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, the turbulence produced by the farms kept the ground in their area warm.
Previous research in 2010 by other US scientists found wind farms could make the nights warmer and days cooler in their immediate vicinity, but those effects could be minimised by changing turbines' rotor design or by building the farms in areas with high natural turbulence.
That research was based on evidence from two meteorological towers over a six-week period.
Although the warming effect shown in that study and the latest research is local, and small compared to overall land surface temperature change, the findings could lead to more in-depth studies.
The authors of the study released on Sunday said: "Given the present installed (wind farm) capacity and the projected installation across the world, this study draws attention to an important issue that requires further investigation."
"We need to better understand the system with observations and better describe and model the complex processes involved to predict how wind farms may affect future weather and climate."
Commenting on the study, Steven Sherwood, co-director of the Climate Change Research Centre at the University of New South Wales in Australia, said: "Daytime temperatures do not appear to be affected. This makes sense, since at night the ground becomes much cooler than the air just a few hundred metres above the surface. The wind farms generate gentle turbulence near the ground that causes these to mix together, thus the ground doesn't get quite as cool."
Research in the United States may cast a shadow over the long-term sustainability of wind power.
The complete report can be downloaded from the following link.
http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1505.html
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