A study by a research team from the University of Albany, New York has raised concern that wind farms could cause significant rise in ground temperatures. The team studied weather satellite data for the Nolan and Taylor territories of west Texas, which house four of the largest wind farms in the US and found that in the 10 years between 2003 and 2011, night time ground temperatures have risen by 0.72 degrees Celsius compared to adjoining areas without wind turbines. Global warming attributed to the burning of fossil fuels is estimated to cause 0.2 degrees Celsius rise in temperature over a similar 10 year period. A near four times higher ground temperature rise due to wind turbine operations could cause a serious setback to wind energy.
More studies are needed before drawing a conclusion
Scientists, including the University of Albany team, are cautioning that more studies are needed before we come to any conclusions. Similar weather satellite data have to be analyzed for other wind farm areas in the US and in other parts of the world. They also warned that such localized warming should not be compared with global warming data.
The rise in ground temperature could be attributed to two possible reasons. One is the heat dissipated from the wind turbines and the associated electric transformers and switches. The other factor could be that the wind turbines pull down warmer air from the upper atmosphere to the ground level, preventing the ground temperatures from falling rapidly. If this theory is correct, daytime ground temperatures in the wind turbine areas should have been lower than the surrounding areas since the upper air is cooler. The Albany team’s study shows no difference in daytime temperatures.
The reasons for concern over ground temperature rise
One of the attractions of wind energy over other renewable energy sources is that the land around the wind turbine can be used for agriculture. In Texas, for example, farmers lease out space for wind turbines at $3000 to $5000 per turbine and continue growing crops around the turbine towers.
The value of agricultural produce from Texas is over $80 billion, several times larger than the value of electricity produced from the wind turbines. If the rise in ground temperature causes any changes in crop yield patterns, farmers could quickly turn away from permitting wind turbines on their agricultural lands.
Worldwide, wind energy has acquired momentum with a 21 percent increase in installed capacity to 238 Gigawatts in 2011. The US has the largest share of 47 Gigawatts and the state of Texas is the biggest with 10.3 Gigawatts. Any adverse reports on agriculture could therefore have impact in other parts of the world including the emerging economies, where much of the new power generation capacity needs to be added.
A small anti-wind power lobby has always argued that wind turbines scare away flying insects and birds that help cross pollination and that the continuous noise causes long term adverse effects. The Albany report may reinvigorate this lobby who could advocate halt of new wind turbine construction until the ground warming data is further investigated.