Proposed Sound Rule for Wind Energy Facilities Public Service Board - - PowerPoint PPT Presentation

proposed sound rule for wind energy facilities
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Proposed Sound Rule for Wind Energy Facilities Public Service Board - - PowerPoint PPT Presentation

Proposed Sound Rule for Wind Energy Facilities Public Service Board Workshop Payam Ashtiani, B.A.Sc. Aercoustics Engineering Limited PayamA@aercoustics.com Dec 2 2016 Noise Emission vs Noise Immission Emission: Noise emitted by a source


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Proposed Sound Rule for Wind Energy Facilities

Public Service Board Workshop Payam Ashtiani, B.A.Sc.

Aercoustics Engineering Limited PayamA@aercoustics.com

Dec 2 2016

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Noise Emission vs Noise Immission

Emission: Noise emitted by a source Immission: Noise received at a given location

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Noise Emission vs Noise Immission

Emission: Noise emitted by a source Immission: Noise received at a given location

Emission Immission

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PRE-CONSTRUCTION NOISE MODELLING

Permitting Stage

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Pre-Construction Noise Modelling

  • Industry accepted modelling methodology agrees well with post construction

measurements.

  • Modelling methods should be standardized and prescribed
  • Institute of Acoustics Good Practice Guide – May 2013
  • ISO 9613-2 widely accepted
  • Modelling parameters important:
  • Ground factor (<=0.5)
  • Termperature / Humidity
  • Sound Power input used (Uncertainty considerations)
  • Considerations for concave ground (valleys)
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POST-CONSTRUCTION NOISE MONITORING

Commissioning stage or in response to noise complaints

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Post-Construction Noise Monitoring

Informed by the past decade of measuring noise from large wind turbines Circa 2005-2007 Unattended simple noise monitors – short term Circa 2007-2008 Attended measurements short to medium term Circa 2008-2010 Sophisticated unattended noise monitors – long term Circa 2011-present More robust, cell connected noise monitors – long term Circa 2014-present Algorithms for objective tonality assessment

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Post-Construction Noise Monitoring - instrumentation

  • Class 1 sound level meter and microphone
  • Secondary wind screen for added protection against

wind induced pseudonoise

  • Anemometer located near microphone
  • Wind speed
  • Wind direction
  • Temperature
  • Humidity
  • Pressure
  • Rain
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  • Preferably at locations with the highest predicted noise impact from the facility
  • Locations where one can reasonably expected downwind conditions to occur more

frequently than others.

  • Locations that are free of significant sources of noise contamination such as busy

roadways, heavily shrubbed or forested areas, or close to other commercial operations

Post-Construction Noise Monitoring - location

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  • 1-minute intervals

Post-Construction Noise Monitoring – data filtering

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Post-Construction Noise Monitoring – data filtering

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  • 1-minute intervals
  • Valid if conditions are conducive to good quality data:
  • No precipitation
  • Separate daytime from nighttime (different fauna)
  • Ensure turbines operating at high noise output
  • Wind direction is not upwind (i.e. only downwind and crosswind acceptable)
  • Wind speed measured at ground level less than 5m/s to minimize ambient noise.
  • Remove intervals with transient events such as car passbys, etc
  • Obtain sufficient number of valid data points with Turbines ON and OFF
  • Bin the data by wind speed and compare ON vs OFF
  • Determine the Turbine contribution through logarithmic subtraction of ambient

Post-Construction Noise Monitoring – data filtering

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Post-Construction Noise Monitoring – data filtering

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Post-Construction Noise Monitoring – assessment

  • Assessment made based on the mean or logarithmic average of the

levels by windspeed

  • Facility contribution determined by ambient correction with data from

the same wind bin

  • Assessment made when there is sufficient data acquired – at least 20

points within a wind bin

  • NOTE: Any 1 individual minute above or below the limit does not

constitute an assessment of compliance or non-compliance.

  • NOTE: the nature of ambient noise is changing constantly and it would

be difficult to defend certainty in knowing if one individual minute was not unduely influenced by transient event contamination

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Tonality

  • Tonality determined by analyzing narrow-band frequency spectra
  • Objective measure of the prominence of a tone
  • Less prone to false negatives than the current 1/3rd Octave method
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Thank you

Payam Ashtiani, B.A.Sc.

Aercoustics Engineering Limited PayamA@aercoustics.com

Dec 2 2016