Reviewing the Facts on Wind Turbine Sound Impacts
Renewable Northwest Project has been actively following the research on this important issue regularly since the early 1990's and will continue to do so. We have compiled the following to help separate the myth from the facts.
Wind Turbine SoundJust like almost anything in life—cars, stereos, your coworkers or the wind itself—wind turbines do make sound. Sound from wind turbines can be mechanical (such as from the gearbox) or aerodynamic (from air moving past the blades). Modern turbine designs have greatly reduced the mechanical sounds to the point where normally what you hear at a wind farm is a light "whooshing" sound of the blades passing through the air. Other factors do play a part, such as distance from the turbine, height, topography, vegetation, and wind conditions, but overall wind farms are very quiet compared to other industrial facilities. In fact, because the wind is blowing whenever the turbines are spinning that "whooshing" sound is often lost in the sound of the wind itself.
Some Basic ComparisonsSounds are often hard to describe, which is why the best way to form your own opinion is to visit a modern wind farm. But since getting to a wind farm isn't easy for most of us, here are a few comparisons of noise levels measured in decibels for various activities1:
The Myth of "Wind Turbine Syndrome"Opponents of wind talk a lot about “wind turbine syndrome,” but what they don't tell you is that it is not a recognized condition or disease of any kind. The term comes from a self published book by Dr. Nina Pierpont. Her conclusions have been debunked by independent scientific studies from government research bodies around the world. Following are some quotes from experts that have reviewed her work:
“While opponents of wind energy have attempted to use self-published reports to block projects, the science is clear. Independent studies conducted around the world consistently find that wind farms have no direct impact on physical health. In fact, with no air or water pollution emissions, wind energy is essential to reducing public health impacts from the energy sector.”2,3
– Robert Dobie, M.D.
David M. Lipscomb, Ph.D.
and Robert J. McCunney, M.D.
“In my review I found no evidence in peer-reviewed medical and public health literature of adverse health effects from the kinds of noise and vibrations heard by wind turbines other than occasional reports of annoyances, and these are mitigated or disappear with proper placement of the turbines from nearby residences. Most studies showing some health effects of noise have been done using thresholds of 70 dBA or higher outdoors, much higher than what is seen in wind turbines.”4
– Dr. Dora Anne Mills, MD, MPH Maine CDC/DHHS
Several studies have looked at various pieces of the issues involved, both with wind turbines specifically and on related noise issues in general. A good summary of the issues can be found in a review done by the Australian National Health and Medical Research Council. That publication found that, "Based on current evidence, it can be concluded that wind turbines do not pose a threat to health if planning guidelines are followed."5
How Do Turbine Noise Rules in the Northwest Compare?
RNP has been an advocate for responsible renewable energy development in the Northwest since our inception. Our local economy, environment, and quality of life depend on making sure that harvesting our natural, renewable resources is done right. We were part of a group of interested parties that worked with the Oregon Department of Energy and the Governor’s office for nearly a year that culminated in new noise rules being set in 1994 for wind development in the state. Those rules set the noise limit from a wind turbine project at 50 dBA for participating landowners and typically 36 dBA for non-participating landowners. A maximum project level of 36 dBA for a non-participating landowner is one of the most robust limits in the world.
While RNP is confident that the current siting regulations are good, RNP will continue to monitor the scientific findings on this issue to ensure that wind energy development in the region adheres to safe standards.
Infrasound and Comparing ImpactsMany arguments against wind turbine noise mention the effects of infrasound, or sound at frequencies outside the range of normal human hearing. Infrasound is all around us, comes from a number of sources and does not pose a threat. In fact, there are very real and far greater threats to human health from fossil fuel energy production. Scientific American recently reported that particulate pollution from fossil-fueled power plants caused more than 30,000 premature deaths, 600,000 asthma attacks and 5 million lost workdays.6
1) Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2001-104.
2) The Oregonian editorial. There's no evidence of health impacts from wind energy. November 26, 2010.
3) Robert Dobie, M.D., is a clinical professor of otolaryngology at University of Texas – San Antonio and University of California, Davis. David M. Lipscomb, Ph.D., is president of Correct Service Inc. in Stanwood, Washington. Robert J. McCunney, M.D., is a research scientist in occupational and environmental medicine at the Massachusetts Institute of Technology’s Department of Biological Engineering.
4) Maine Center for Disease Control & Prevention. Wind Turbine Neuro-Acoustical Issues, June 2009.
5) Australian National Health and Medical Research Council. Wind Turbines and Health: A Rapid Review of the Evidence, p. 6.
6) Scientific American, "The Health Care Burden of Fossil Fuels," August 31, 2011.