Wind Farms: Good for the Environment, Bad for the Ears?
Here is the good news: wind energy is clean and renewable. It doesnt produce toxic waste that causes environmental damage, or deplete natural resources such as coal, oil or gas.
According to the American Wind Energy Association (AWEA), 80 percent of people the group had surveyed are enthusiastic about wind energy and consider it to be one of the most popular energy technologies.
The bad news, however, is that for many people living in the vicinity of wind farms, the noise produced by the rotating turbines is irritating to the ears.
Getting the wind of renewable energy
Wind farms are clusters of dozens of machines that capture wind energy and convert it into electricity. According to Wind-Works Org., in 2007 there were approximately 90,000 turbines operating worldwide, with two-thirds of them in Europe.
The U.S. states with the most wind production are California, Texas, Iowa, Minnesota, and Oklahoma. The world's largest wind farm, the Horse Hollow Wind Energy Center in Texas, has 421 wind turbines that generate enough electricity to power 230,000 homes per year.
That may very well change in the future. The U.S. Department of Energy has recently released a report stating the country is capable of increasing its wind-generated electricity output to 20 percent by 2030.
Good hearing: gone with the wind?
Dependence on wind energy seems to be a double-edged sword. While wind farms are a critical part of the solution to global warming, the thumping noise emitted by the fast-moving blades slicing through the air is a matter of concern to people living near the farms, as well as to hearing health experts.
Dr. Oguz A. Soysal, professor and chairman of the Department of Physics at Frostburg State University in Maryland, measured sound levels more than a mile away from a turbine wind farm in Pennsylvania and found that typical noise levels of 65-70 decibels equivalent to a washing machine or a vacuum cleaner were even louder at night. The nighttime turbine noise, in fact, was keeping people living 1.5 miles away awake.
The World Health Organization (WHO) recommends that the level of continuous noise outside private households should be no more than 45 decibels, and it should not exceed 30 decibels indoors. Higher levels, the WHO warns, may disturb sleep and negatively impact overall health.
Another study, commissioned in 2006 by the UK Noise Association, found that the stress and annoyance some people experience as a result of noise from wind farms is made worse by the flicker effect created by the rotating blades of the turbines.
No scientific data suggests that the noise from the rotating turbines can lead to permanent or debilitating hearing loss, but the disturbances can cause insomnia, headaches, dizziness, exhaustion, irritability, depression, problems with concentration, and tinnitus. Research has unearthed persistent complaints from people saying they not only hear the noise but can feel disturbance in their bodies, concludes British anti-noise advocate John Stewart, who reviewed the research into the wind-farm noise.
The Noise Association is not against the wind farms, but argues for sensible implementation of turbines, farther than a mile from where people live.
In the ear of the beholder
The argument doesnt always resonate with wind energy advocates who say noise may be generated by old, pre-1980s turbines, or newer models operating in certain types of hilly terrain. But the vast majority of modern wind turbines, they say, have been designed to drastically reduce the noise. In fact, the British Wind Energy Association (BWEA) cites an independently commissioned study showing that, of the 126 wind farms operating in the UK, only five have low frequency noise problems.
The BWEA says that while there is always low frequency noise present in any ambient quiet background, it has been repeatedly shown by measurements of wind turbine noise undertaken in the UK, Denmark, Germany and the USA over the past decade, and accepted by experienced noise professionals, that the levels of low frequency noise and vibration radiated from modern, upwind configuration wind turbines are at a very low level, so low that they lie below the threshold of perception.
Furthermore, the sound of a working wind farm, the BWEA insists, is actually less than normal road traffic or of the noise the wind itself makes in the environment.
The BWEAs U.S counterpart, the AWEA, sums up the noise argument this way: As with beauty, often said to be in the eye of the beholder, the degree to which a noise is bothersome or annoying is largely in the ear of the hearer. What may be a soothing and relaxing rhythmic swishing sound to one person may be quite troublesome to another.