By John Salak –
Wind farms are both loved and hated. Those enamored with them cite their promise to produce low-cost, clean, sustainable energy that can also support local economies. Those less than thrilled by these turbine-centric towers claim they threaten birds, generate noise pollution and ruin the visual aesthetics of remote landscapes.
It’s unclear whether the potential risks cited by Energy.gov are legitimate or just a byproduct of the NIMBY (Not In My Back Yard) movement. An Australian research team, however, recently undercut the wind farms’ noise pollution risks these turbines present, at least for a short time.
Flinders University acknowledged that wind farms do raise noise levels, which can interrupt the sleep of a small percentage of nearby residents. However, the researchers report that wind farm noise is no more disruptive than road traffic. The sound of passing cars and trucks may be more unsettling than anything coming off the turbines.
The Australian researchers concluded after a five-year study that covered more than 460 sleep study nights involving almost 70 participants. The project focused on playing on repeat 20-second wind farm and road traffic noise samples during participants’ sleep using three different sound pressure levels. Separately, they tested if longer three-minute noise samples, including very low-frequency wind farm infrasound alone, resulted in sleep disturbance.
The study measured sleep patterns using electroencephalography (EGG), hearing tests and a range of daytime listening tests.
“To capture the most representative wind farm noise features and levels, we used noise samples from long-term measurements of wind farm noise. These were then reproduced in the sleep laboratory to replicate real-life noises in a much more controlled environment than is possible in field studies, where wind and noise conditions are highly variable,” explained Dr. Bastient Lechat, an acoustics expert.
The findings showed that wind turbine noise pollution and road traffic noise disrupt sleep, depending on noise loudness and sleep depth at the time of noise exposure, reported Professor Peter Catcheside, the study’s chief investigator.
“However, at realistic levels, these effects were quite small. We also found no evidence to suggest that wind farm noise is any more disruptive to sleep than road traffic noise. At the highest exposure level, road traffic noise was a little more sleep disruptive than wind farm noise,” he added.
They also found that wind farm infrasound at realistic levels was not audible to the human ear while a person was awake and produced no evidence of sleep disruption.
“Our results align with previous studies and showed that infrasound played at realistic levels was not audible during wakefulness and produced no detectable EEG changes during sleep. Infrasound is therefore unlikely to explain noise complaints from wind farms, suggesting that other low-frequency audible rumbling and thumping components deserve more attention towards better understanding wind farm noise effects on sleep,” Catcheside added.
The study provides evidence that wind farms are no more disruptive to sleep than road traffic noise. However, research acknowledged that people who are particularly noise-sensitive may find it more difficult to nod off when noise levels are noticeable.