Despite their potential as a clean, renewable source of energy, wind farms have not been without controversy, with complaints ranging from noise to aesthetic impact to sickness as a result of the turbines.
Still, turbines continue to proliferate across many parts of the world. According to an article in The Week magazine, global wind generating capacity jumped by 21 per cent last year and is expected to grow from 238 gigawatts of electricity at any one time now to around 500 gigawatts by 2016.
But the technology struck further controversy on April 29 when an article published in the scientific journal Nature suggested that the turbulence created by large wind farms may actually have a warming effect of their own – an interesting phenomenon for a technology which is supposed to help reduce global warming.
According to the article, researchers at the State University of New York at Albany looked at satellite data from 2003 to 2011 across a wide swath of West Texas, where four of the world’s largest wind farms were built during that period. Nighttime temperatures in the air surrounding the wind-power facilities were 1.3 degrees higher than in other nearby areas. Furthermore, authors of the report say the overall results show a significant warming trend of up to 0.72 degrees Celsius per decade within the immediate vicinity of wind farms when compared with nearby non-wind-farm regions.
“We attribute this warming primarily to wind farms,” the authors say.
Why does it happen? (And does local warming matter?)
Under normal circumstances, local temperatures drop at night as the sun goes down and cooler air settles on the ground. According to the study, however, the turbulence created by wind turbines stirs up the chilly air, causing it to mix with a warmer layer of air on top and preventing the temperature from falling as much as it otherwise would. In other words, the turbines ‘pull down’ warm air from above. Such findings support conclusions from previous research in 2010 that found higher nighttime temperatures and cooler daytime temperatures in areas immediately surrounded by wind farms.
Does this matter, given the localised nature of the warming? Some think so. For a start, even if locally warmer temperatures do not affect the climate on a global scale, they may create problems in the immediate area. In an article in Discovery News, for example, journalist Eric Niller postulates that the warming effect of wind farms in Texas observed through the study may have impacted plant growth and rainfall patterns, exacerbating the impact of the drought experienced during the period by local farmers.
Furthermore, given the worldwide proliferation of turbines, there are fears that the combined impact of an ever-growing number of turbines producing local effects could indeed add up to some form of larger-scale impact on global temperatures.
Defending the turbines
Commentators such as Trevor Quirk, a contributor to The Christian Monitor, however, are quick to defend wind power.
Quirk accuses much of the media coverage surrounding the study of being misleading and using sensationalist headlines. He points out that while higher temperatures in wind turbine areas were observed, even the report’s authors acknowledge that further study is required to understand the exact cause of the apparent link. Also, he points out that the authors have cautioned against any linear interpolation of results for the particular study area over the particular study period into other regions over longer periods.
Furthermore, Blade says wind turbines simply redistribute existing heat as opposed to adding more heat to the earth.
“If it were true that the spinning blades of wind turbines increased the overall temperature of the planet, as opposed to simply redistributing thermal energy, we would have to rewrite some basic laws of physics, particularly the second law of thermodynamics,” he says. “This is an important distinction from the burning of fossil fuels, which produces gas that increases how much of the sun’s energy the Earth retains. In this respect, this process contributes to a globally warming climate because the source of energy (the sun) is apart from the system that is warmed (the earth.)”
Blowing up a controversy
As a source of clean, renewable energy, wind farms are becoming an increasingly important aspect of the energy mix throughout much of the world.
But as the latest study shows, controversy surrounding the turbines will not go away anytime soon.