As a rainbow was seen over power-generating wind turbines located on a wind farm near North Palm Springs, California, in 1999, the question of whether or not wind turbines . could affect the weather, became a topic for a scientific study.(Associated Press, "Wind farms can change the weather," Eugene Garcia, Oct. 4, 2010)
Now the authors of this recently-released study, which was published in the Proceedings of the National Academy of Science, have confirmed that large-scale wind farms can influence local air temperatures.
Cooling Caused by Wind Farm
Data was collected over a seven-week period during the summer of 1999, at the San Gorgonio wind farm near Palm Springs. The study revealed that the wind farm caused the local area to cool down during the day and warm up at night, according to authors Somnath Baidya Roy and Justin J. Traiteur of the University of Illinois.
On one day, study readings showed a temperature of 100 degrees, at 1:00 p.m., upwind of the wind farm, but this temperature reading had dropped to about 93 degrees downwind, due to the effects of the wind farm. The authors deduced that the turbulence generated by the turbine blades enhanced the vertical mixing of warm and cold air, leading to the temperature changes.
"To the best of our knowledge, this is the only meteorological field campaign conducted in an operational wind farm," the authors wrote in the study. "The wind farm consisted of 23-meter-tall turbines with 8.5-meter-long rotor blades arranged in 41 rows that were spaced 120 meters apart."
Crop Productivity Could be Affected
The two scientists who conducted this study point out that, because many wind farms are located on agricultural land, local weather changes could affect crop productivity.
To minimize the impact of temperature changes on crops, the authors of the study suggested that changes can be made to rotor design to minimize these effects. As well, locating wind farms in regions with high natural turbulence would also result in reduced temperature changes. The study used a 25-year-long climate dataset to identify regions in the world with high natural turbulence. Many regions identified by the study authors, such as the U.S. midwest and great plains, are also rich in wind resources, making them ideal candidates for low-impact wind farms.
Changes in Blade Design Characteristics
Another factor which will undoubtedly impact the affect of wind farms on local atmospheric conditions, is the new design criteria being used for wind turbine blades, involving much longer blades, as long as 50 meters, and modified aerodynamic characteristics of the blades, as well as higher towers.
There are a number of proposed new wind farms scheduled to be established in the U.S., notably in the Texas Gulf region, along the Atlantic Coast, and in the great plains and upper midwest.
In the spring of 2009, President Obama stated that he would allow turbines along the Atlantic as one way to help meet a goal by environmentalists and the industrial sector of generating 20 percent of the nation's electricity through wind by 2030. Currently about one percent of U.S. power comes from wind, according to the American Wind Energy Association.
Duane Sharp - I am a retired professional engineer (electronics), with over 40 years of writing experience in technology topics, with a focus on the IT ...
