Reducing noise when it comes to wind turbines: your questions answered

Photo courtesy of RWDI.

Wind turbines, like other mechanical equipment, generate sound. In our work with local stakeholders in communities where we have plans for proposed wind projects, we’re often asked questions about turbines and sound/noise.  Here are the answers to the most frequent questions.

What are the sounds I hear?

Wind turbines generate two types of sound: aerodynamic and mechanical.

  • Aerodynamic sound is generated from the blades as they pass through the air.  The aerodynamic sound of a wind turbine is usually described as a “whoosh,” or “swishing” sound.
  • Mechanical wind turbine sound is generated from the inner working components and rotating gears of a wind turbine.  While a component of the overall sound, mechanical sound has been reduced through improved insulation and overall design.

How loud are the sounds (or noises)?

Sound from wind turbines is measured according to a detailed international standard. Government requirements around the world require the sound from wind farms to be kept to very low levels at all nearby dwellings. In Canada, turbines are typically located a minimum of 550 metres (0.3 miles away) from occupied homes, in compliance with provincial government requirements.  At that distance, the sound from the turbine will have a sound pressure level of approximately 40 decibels (dB) at the outside of the residence. A comparable sound would be the hum from a running refrigerator at around 40 decibels.

It is important to remember that ambient sounds change at different times of the day, usually being lower at nighttime, as activity from farming, other industry and transportation decreases overnight. Because of this, turbine sound may be more noticeable when the background noise is reduced.

When planning a project, how do you factor in noise control?

In the development of a wind project, Suncor follows specific sound regulations that are administered by the provincial governments as well as our best practices. For example, in Alberta, a Noise Impact Assessment (NIA) is required for all industrial wind power project applications.  This assessment will consider other operational or proposed wind facilities nearby the project area.  Along with the sound limits, there are also distance constraints that create space between areas of concern and the wind project. Common areas of note include property lines, inhabited structures and public roads, as well as communication and electrical lines. A turbine layout can be revised a number of times based on changes to environmental restrictions, different turbine technology and stakeholder consultation.

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