A five-year Australian study of the impact on the noise of wind turbines on sleep patterns found that short exposure to windfarm and road traffic noise triggers a small increase in waking people up that can fragment their sleep patterns. The Flinders University research concluded that windfarm noise isn’t any more disruptive to sleep than road traffic noise.
The study included 460 sleep study nights from 68 participants who spent seven consecutive nights in a sleep laboratory. Flinders University presented three new scientific publications from the study designed to better understand the impact of windfarm noise on Australians.
The researchers also found that windfarm infrasound at realistic levels was not audible to the human ear while awake and produced no evidence of sleep disruption. The findings presented at the International Conference on Wind Farm Noise in Dublin, Ireland, on June 22, and have not yet been journal peer reviewed.
The study was of interest to opponents of the proposed $300-million Nimbus Wind Facility proposed near County Roads (CR) 905 and 920 on a ridge south of Green Forest.
Caroline Rogers, whose home on CR 905 would be surrounded by three wind turbines, said she doesn’t understand why there was a need to do a five-year lab study when thousands of people have already told their stories about being disrupted by noise from wind turbines.
“The study doesn’t take into account 24 hours a day living around and under wind turbines,” Rogers said. “It’s a select study during night hours. They are not considering shadow flickering, and noise during day which puts a toll on the body as well.”
The researchers also found that windfarm infrasound at realistic levels was not audible to the human ear when people were awake and produced no evidence of sleep disruption.
Rogers said it may be true not everyone is affected by infrasound, just like there are people who can sleep through loud noises that wake others.
“For those who are affected, many have permanently left their homes, others leave town a few times a month just to get sleep elsewhere,” Rogers said. “That’s when you know the problem is real because sleeping returns to normal when they are away from turbines and repeats once home.”
The study played 20-second wind farm and road traffic noise samples repeatedly during participants’ sleep using three different sound pressure levels to compare their sleep disruption responses between the two different noise types. Nimbus opponent E. Richard Williams, who lives on CR 905, said he and his wife chose to live in the country for the peace, quiet, tranquility and isolation. He said after reviewing the article, he doesn’t believe it is an accurate study of the noise problems created by a wind farm.
Williams said a news report by Mike Landis of KOLR-10 News in Springfield, Mo., a few weeks ago televised the actual noise created, which the reporter likened to that of a jet engine.
“I consider the Australian study in no way reflective of the noise level as presented from the windfarm noise in Missouri as reported by KOLR,” William said. “Also, autos passing by are not constant while turbines are almost non-stop from my understanding. I think I would prefer the noise of autos passing our home on a seldom basis – where we live you can actually count the number of trucks and autos every day – rather than the constant ‘jet roar’ of wind turbines all the time.”
A press release from Flinders University stated that participants were recruited from four groups, including people living near a windfarm with and without noise related sleep difficulties, a group of residents living near a busy suburban road and people living in quiet rural areas.
“In order to capture the most representative windfarm noise features and levels, we used noise samples from long-term measurements of windfarm noise,” Dr. Bastient Lechat, an acoustics expert on the research team, said. “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. The study included direct sleep measurements using electroencephalography (EEG) as well as hearing tests and a range of daytime listening tests.”
Professor Peter Catcheside, a sleep expert from Flinders University and the chief investigator, says that the findings show that both windfarm noise and road traffic noise disrupt sleep, depending mainly on noise loudness and sleep depth at the time of noise exposure.
“However, at realistic levels, these effects were quite small,” he said. “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.”
Catcheside says their study 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 windfarms, suggesting that other low frequency audible rumbling and thumping components deserve more attention towards better understanding windfarm noise effects on sleep,” he said.
Catcheside says that while this study provides strong evidence that windfarm noise is not more disruptive to established sleep than road traffic noise, this does not rule out that people who are particularly noise sensitive or annoyed may find it more difficult to get to sleep when noise levels are noticeable.
Scout Clean Energy, the developer of the proposed Nimbus Wind Facility, has said it has all the leases needed from private landowners to develop the project that would have 43 wind turbines more than 500 feet tall, with some more than 650 feet tall.
Scout has said the project would help provide green energy needed to combat climate change while providing millions in lease revenues to property owners, and millions in property taxes to Carroll County.
Scout has said it needs no permits for the project from Carroll County, which does not have zoning regulations, or from the Arkansas Public Service Commission to build the facility. Scout Public Relations representative Chad Thompson did not return a request for comment by press time.