Renewable Energy - Wind Turbine Noise
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Noise: Are wind turbines noisy?
Wind turbines are large pieces of equipment, so they can be expected to make some level of sound.
Sound from wind turbines comes from two general sources: the mechanical equipment itself, and the sound from the interaction of the air with the turbine parts (primarily the blades).
Modern large-scale wind turbine manufacturers have virtually eliminated sound from mechanical sources due to improved design and insulating - if mechanical noise is prevalent, it is usually due to a malfunction.
They have also made improvements in the design of turbine unit and blades to reduce the sound produced by aerodynamic effects.
Generally, wind turbines radiate more noise as the wind speed increase.
The chart below illustrates the sound impacts as experienced by humans from various sources:
The World Health Organization has established that a sound level of around 30 dB in the room where people sleep is desirable.
As a comparison, the compressor from a refrigerator operates between 40 to 45 dB, and a normal conversation registers at around 60 dB.
Sound from wind projects are measured and evaluated in a way that ensures no ill effects on health.
At a distance of 350 metres outside, a wind energy project would have a noise level of between 35 and 45 dB.
The degree to which humans are affected by the sound from wind projects is largely related to proximity to the project and the degree of sound from other sources, as related to the residence of a person.
Obviously, the closer you are to a turbine(s), the more noise you will be able to hear.
But, the noise you hear from a wind turbine may actually be overcome due to the sound of the wind blowing.
It can be further lessened by other sounds, such as the wind through trees, cars on a highway, waves on a beach, other industrial operations, etc.
Most jurisdictions have chosen to mitigate the issue of sound from wind turbines by establishing minimum setbacks from occupied dwellings.
This can be in the form of a minimum distance (i.e. 500 metres from turbine to residence and/or three times the height of the turbine).
These minimum distances provide a buffer zone that reduces the noise from wind projects to a level that does not affect human health.
The Government of Nova Scotia is well aware of the issues associated with sound from wind projects, and reviews potential impacts very carefully as part of the environmental assessment process.
Each proposed project is dealt with on its own merits through the Environmental Assessment, taking into account the:
- number and placement of the wind turbines,
- local landscape and land usage,
- amount of sound produced by the type of wind turbine being used, and
- sound levels at residences and other occupied dwellings.