Noise and Wind Turbines

The Canadian Wind Energy Association claims that modern wind turbines are not noisy.[2] They also assure the public that “it’s possible to carry on a normal conversation at the base” of a wind turbine and at 300 meters the sound is like a “whispering voice.”[3]

In light of this information one may ask why are people reporting suffering from adverse health effects and why have families abandoned their homes?

The answer is wind turbines are noisy. A single modern wind turbine emits approximately 105 dBA of industrial noise pollution.[4] To put 105 dBA in perspective, this is between the sound power level of a pneumatic hammer drill and a rock band.[5]  Additional wind turbines in the neighbourhood combine to increase the noise level.

Wind turbine noise propagation is complex. A person standing under a wind turbine may experience much less noise than someone else living in a home hundreds of meters away from the base of the wind turbine.

[6]

In their best practices The Canadian Wind Energy Association acknowledges that noise complaints are not uncommon when wind turbines are placed close to homes.[7]

Wind turbine noise is not only loud it is also complex.[8],[9],[10]

“Sound generated by wind turbines has particular characteristics and it creates a different type of nuisance compared to usual urban, industrial, or commercial noise. The interaction of the blades with air turbulences around the towers creates low frequency and infrasound components, which modulate the broadband noise and create fluctuations of sound level. The lower frequency fluctuation of the noise is described as ‘swishing’ or ‘whooshing’ sound, creating an additional disturbance due to the periodic and rhythmic characteristic.”[11]

Members of the health care community recognize that of these noise characteristics may have a particularly pronounced effect on people exposed to them.[12],[13]

The American and Canadian Wind Energy Associations appear to disagree and are of the opinion that wind turbine noise is not unique.[14]

In September 2009 the Maine Medical Association passed a resolution that calls for research and development of wind turbine noise guidelines to protect human health.[15]

Many who have studied the issue of wind turbine noise advocate for wind turbine specific noise regulations designed to protect the public from the potential adverse effects. [16],[17],[18] Health based wind turbine noise limits would likely prescribe lower noise limits than those of other sources of noise.

In some jurisdictions such as Ontario the exact opposite has occurred where the wind energy industry has been granted the ability to subject family homes to higher levels of noise pollution than other industries.[19] Higher noise levels benefit the economic interests of the wind industry as noise levels affect the spacing of wind turbines and ultimately the cost of electricity produced.[20]

Currently there is no authoritative international guideline for wind turbine noise designed to protect human health. Wind turbine noise regulations vary by jurisdiction.

A family home in Ontario, Canada could be subjected to 53 dBA while families in British Columbia, Canada or South Australia would be limited to 40dBA and 35 dBA respectively.[21]

These differences are significant as a 10 dBA increase is subjectively heard as an approximate doubling in loudness.[22]

The American and Canadian Wind Energy Associations do not appear to support the development of authoritative wind turbine noise guidelines designed to protect human health. On the contrary they are of the opinion that the authoritative noise guidelines of the World Health Organization need not be adhered to.[23]