Welcome to

Lawrence Technological University’s

Delphi Inquiry

into

Wind Turbine Noise Issues December 3, 2004

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Delphi InquiryDelphi InquiryImpact of Wind Turbine NoiseImpact of Wind Turbine Noise

AgendaAgenda

PresentationPresentationOpen DialogOpen DialogSurvey (first iteration)Survey (first iteration)

Today’s PresentationToday’s Presentation

IntroductionIntroductionWho we areWho we areWhy we are here Why we are here Today’s goalToday’s goalDelphi InquiryDelphi Inquiry

Noise basic conceptsNoise basic conceptsDefinitions and Definitions and propertiespropertiesMeasurementsMeasurementsPropagationPropagation

Noise impactNoise impactIndividual healthIndividual healthCommunity responseCommunity response

Turbine noiseTurbine noiseBackground on Background on turbinesturbinesNoise sourcesNoise sourcesNoise modeling Noise modeling

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IntroductionIntroduction

Who We AreWho We Are

Lawrence Technological UniversityLawrence Technological UniversityLead researcher: Daniel J. Lead researcher: Daniel J. AlbertsAlbertsFaculty advisors: Dr. Robert Fletcher, Dr. Brian Faculty advisors: Dr. Robert Fletcher, Dr. Brian PedellPedellResearch assistants: Kevin Research assistants: Kevin PawlowskiPawlowski, Tim , Tim BedraBedra

Collaborative PartnersCollaborative PartnersState of Michigan Energy OfficeState of Michigan Energy OfficeMichigan Wind Working GroupMichigan Wind Working GroupDTEDTE

Why We Are HereWhy We Are Here

Wind Powering America InitiativeWind Powering America InitiativeMichigan’s estimated wind potential: 16,000 MWMichigan’s estimated wind potential: 16,000 MWDevelop informed opinionsDevelop informed opinionsAnalyze and build consensus on wind turbine Analyze and build consensus on wind turbine siting issuessiting issuesHelp validate and supplement pending state Help validate and supplement pending state guidelines guidelines Help municipalities develop local zoning Help municipalities develop local zoning ordinancesordinances

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Today’s GoalToday’s Goal

Introduce the Delphi ProcessIntroduce the Delphi ProcessBasic noise conceptsBasic noise conceptsNoise impact on healthNoise impact on healthWind turbine noiseWind turbine noiseOpen dialogOpen dialog

Ask questionsAsk questionsDiscuss opinionsDiscuss opinions

First round of survey First round of survey

Delphi ProcessDelphi Process

Present basic informationPresent basic informationOpen dialog Open dialog Answer survey questionsAnswer survey questionsAnalyze resultsAnalyze resultsRepeatRepeat

Goal: develop a consensus of Goal: develop a consensus of INFORMED opinionsINFORMED opinions

Open DialogOpen Dialog

Discussion: views are presented and Discussion: views are presented and defendeddefendedDialog: openly discuss ideas and views to Dialog: openly discuss ideas and views to help develop a new understandinghelp develop a new understanding

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NoiseNoiseBasic ConceptsBasic Concepts

What is Sound?What is Sound?

A repeating cycle of A repeating cycle of compressed and compressed and expanded airexpanded airExerts pressure on Exerts pressure on the receiverthe receiver

Speaker

Cycle

Compressed Air

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Basic Characteristics Basic Characteristics Sound PowerSound Power

energy of sourceenergy of sourceSound PressureSound Pressure

Loudness or amplitude Loudness or amplitude Measured in decibels Measured in decibels (dB) (dB)

FrequencyFrequencyCycles per second, or Cycles per second, or Hertz (Hz)Hertz (Hz)

DurationDuration

Speaker

Cycle

Compressed Air

Sound PowerSound Power

Total energy of soundTotal energy of soundGiven with specificationsGiven with specificationsCalculatedCalculatedOne of many factors used to determine:One of many factors used to determine:

Distance sound will travel Distance sound will travel LoudnessLoudness

Not used to determine exposure or impactNot used to determine exposure or impact

Sound PressureSound Pressure

Measures perceived loudnessMeasures perceived loudnessMeasured at the receiverMeasured at the receiverBasis for:Basis for:

Noise assessmentNoise assessmentHazard exposureHazard exposureExposure standardsExposure standards

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Sound Pressure ScaleSound Pressure Scale

Logarithmic scaleLogarithmic scaleConverted to dBConverted to dBThreshold = 0 dBThreshold = 0 dBPain = 140 dBPain = 140 dBIntervalsIntervals

11--3 dB noticeable3 dB noticeable33--5 dB clearly 5 dB clearly noticeablenoticeable10 dB twice as loud10 dB twice as loud

FrequencyFrequency

Frequency = number of cycles per secondFrequency = number of cycles per secondMeasured in cycles, or Hertz (Hz)Measured in cycles, or Hertz (Hz)

Frequency RangesFrequency Ranges

30 30 –– 40 dB40 dB< 16 Hz< 16 HzInfra soundInfra sound

NANA2 Hz2 HzThresholdThreshold

NANA20 20 –– 250 Hz250 HzLow frequencyLow frequency

NANA100 Hz 100 Hz –– 3 kHz 3 kHz Speech Speech

120 120 –– 140 dB140 dB20 Hz 20 Hz –– 20 kHz20 kHzNormal hearingNormal hearing

Pain ThresholdPain ThresholdRangeRange

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Frequency ComponentsFrequency ComponentsTonalTonal

Single frequencySingle frequencyExample: Musical NotesExample: Musical Notes

Narrowband NoiseNarrowband NoiseMultiple frequencies over a Multiple frequencies over a narrow rangenarrow range

Broadband NoiseBroadband Noisemultiple frequencies over multiple frequencies over large rangelarge rangeExamples: wind, fans, Examples: wind, fans, motors, crowds, etc.motors, crowds, etc.

Adjusted ScalesAdjusted Scales

Adjusted Scales (Continued)Adjusted Scales (Continued)

Approximates sound pressureApproximates sound pressureCC

Approximates noisiness of aircraft Approximates noisiness of aircraft engines engines

DD

Used for Infrasound Used for Infrasound GG

No informationNo informationBB

Approximates frequency response of Approximates frequency response of hearinghearing

AA

Usage Usage ScaleScale

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DurationDurationContinuous Continuous

FansFans

IntermittentIntermittentCars, airplanes, Cars, airplanes, telephonetelephone

ImpulseImpulseFirecrackersFirecrackers

Noise Exposure IndicatorsNoise Exposure Indicators

Maximum noise level (Maximum noise level (LLmaxmax))Equivalent continuous sound (Equivalent continuous sound (LLeqeq))Sound exceeded a percent of time (LSound exceeded a percent of time (L1010, L, L9090))DayDay--night average sound level (night average sound level (LLdndn))Speech interference level (SIL)Speech interference level (SIL)OtherOther

ISO 1996ISO 1996--2 rating level (2 rating level (LLrr))Perceived noise level (PNL)Perceived noise level (PNL)Noise pollution level (LNoise pollution level (LNPNP))

LL9090, , LLeqeq, L, L1010

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Attenuation Attenuation (Reduction of Sound Energy)(Reduction of Sound Energy)

Primary InfluencesPrimary InfluencesDistance Distance Frequency componentsFrequency componentsWind directionWind direction

Other influencesOther influencesTemperature, humidity, surface materials, Temperature, humidity, surface materials, buildingsbuildings

Attenuation by DistanceAttenuation by Distance

Doubling the distance reduces the sound level Doubling the distance reduces the sound level by six decibels. by six decibels.

Frequency AttenuationFrequency Attenuation

Higher frequencies travel further.Higher frequencies travel further.

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Attenuation by WindAttenuation by Wind

Noise ImpactsNoise ImpactsHealth Effects and Community Health Effects and Community

ResponseResponse

Potential ImpactsPotential Impacts

Most common ImpactsMost common ImpactsHearing lossHearing lossSleep disturbanceSleep disturbanceSpeech interferenceSpeech interference

Other ImpactsOther ImpactsHeadaches, constricted arteries, weakened Headaches, constricted arteries, weakened immune system, fatigue, irritabilityimmune system, fatigue, irritability

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Induced Hearing LossInduced Hearing Loss

Temporary or Temporary or permanent threshold permanent threshold shiftsshiftsLoss occurs in Loss occurs in frequency rangesfrequency rangesAffected by total Affected by total energy of exposureenergy of exposureNIOSHA NIOSHA recommendationsrecommendations

¼ hour¼ hour115 dB115 dB

½ hour½ hour110 dB110 dB

2 hours2 hours100 dB100 dB

4 hours4 hours95 dB95 dB

8 hours8 hours90 dB90 dB

Max Max ExposureExposure

Sound Sound LevelsLevels

Recommended ExposuresRecommended Exposures

Speech InterferenceSpeech Interference

Based on distance Based on distance between speaker and between speaker and listenerlistenerNormal speaking Normal speaking voicevoice

10 ft10 ft48 dB48 dB6 ft6 ft54 dB54 dB3 ft3 ft59 dB59 dB1 ft1 ft68 dB68 dB

.5 ft.5 ft75 dB75 dB

Max Max DistanceDistance

Ambient Ambient NoiseNoise

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Sleep DisturbanceSleep Disturbance

Increases time to fall asleepIncreases time to fall asleepDisturbs sleep patternsDisturbs sleep patternsDecreases quality of REM sleepDecreases quality of REM sleepDaytime noise exposure effects sleepDaytime noise exposure effects sleep

Sleep DisturbanceSleep Disturbance

60 dB wakes 90% of people60 dB wakes 90% of people55 dB affects REM cycles and increases 55 dB affects REM cycles and increases time to fall asleeptime to fall asleep4040--45 dB wakes 10% of people45 dB wakes 10% of people35 dB considered the threshold for 35 dB considered the threshold for optimum sleeping conditionsoptimum sleeping conditions

Sleep Disturbance Sleep Disturbance LLeqeq does NOT does NOT correlate with sleep correlate with sleep disturbancesdisturbancesGreatly affected byGreatly affected by

Volume peaksVolume peaksNumber of eventsNumber of events

WHO recommends: WHO recommends: LLeqeq ≤≤ 3030--35 dB 35 dB LLmaxmax ≥≥ 45 dB should 45 dB should not occur more than not occur more than 1010--15 times per night15 times per night

8860 dB60 dB

404045 dB45 dB

Number of Number of PeaksPeaks

LLmaxmax

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ISO Recommendation 1996ISO Recommendation 1996--19711971

Basic Outdoor criteria Basic Outdoor criteria of 35 of 35 –– 40 40 dB(AdB(A))Adjust for district Adjust for district types types Adjust for time of dayAdjust for time of day

Evening: Evening: -- 5 dB5 dBNight: Night: --10 to 10 to --15 dB15 dB

+15+15Urban mixedUrban mixed

+10+10Urban Urban residentialresidential

+5+5SuburbanSuburban

00RuralRural

Adjustment Adjustment dB(AdB(A))

District Type District Type

Community ResponseCommunity Response

Vigorous Community Vigorous Community ActionAction

20 dB20 dB

Threats of Community Threats of Community ActionAction

15 dB15 dB

Widespread ComplaintsWidespread Complaints10 dB10 dB

Sporadic ComplaintsSporadic Complaints5 dB5 dB

Estimated Community Estimated Community ResponseResponse

Increase in NoiseIncrease in Noise

Wind Turbines Wind Turbines

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Size of Today’s TurbinesSize of Today’s Turbines

Today’s Common ModelsToday’s Common Models

1.8 MW1.8 MW

4.5 MW4.5 MW

2 MW2 MW

SizeSize

98 98 –– 109 109 dB(AdB(A))V80V80VestasVestas

107 107 dB(AdB(A))E112E112EnerconEnercon

102 102 dB(AdB(A))E70 E70 EnerconEnercon

Sound PowerSound PowerModelModelMfgMfg

Types of Turbine NoiseTypes of Turbine NoiseMechanical Mechanical

Sources: gearbox, Sources: gearbox, generator, and bearingsgenerator, and bearingsPredominant with small Predominant with small wind turbines (rotor wind turbines (rotor diameter less that 20 m)diameter less that 20 m)

AerodynamicAerodynamicSource: rotor blades Source: rotor blades sweeping through the airsweeping through the airPredominant with larger Predominant with larger turbinesturbines

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Mechanical Noise ReductionMechanical Noise Reduction

Insulation around the generator, gears, and Insulation around the generator, gears, and other moving parts located in the turbine nacelle.other moving parts located in the turbine nacelle.Soundproofing and mounting equipment on Soundproofing and mounting equipment on soundsound--dampening buffer padsdampening buffer pads

Aerodynamic NoiseAerodynamic Noise

Tips Speed RatioTips Speed Ratio

Blade PitchBlade Pitch

Aerodynamic Noise ReductionAerodynamic Noise Reduction

Move rotors upwindMove rotors upwindDownwind blades Downwind blades produce an produce an intermittent thumping intermittent thumping sound. sound.

Raise the cutRaise the cut--in in speedspeedChange the pitch of Change the pitch of the bladesthe blades

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Blade PitchBlade Pitch

Noise ComponentsNoise Components

Covers a broad range of frequenciesCovers a broad range of frequencies

Modeling Turbine NoiseModeling Turbine Noise

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Siting Guidelines and NoiseSiting Guidelines and Noise

5050--55 dB, Low frequency (555 dB, Low frequency (5--100 Hz) 100 Hz) limited to 67limited to 67--75 dB75 dB

Riverside Riverside County, CACounty, CA

60 60 dBAdBA or 5 or 5 dBAdBA above background above background measured at nearest dwellingmeasured at nearest dwelling

CA StateCA State

50 50 dBAdBA measured at the nearest measured at the nearest property lineproperty line

FennerFenner, NY, NY

Statewide Noise Pollution LawsStatewide Noise Pollution LawsMN and ORMN and OR

Further Reading

Wind Energy Dept. of Energy www.eere.energy.gov/windpoweringamerica National Renewable Energy Lab www.nrel.gov/wind/working_wpa.html American Council on Renewable Energy www.acore.org American Wind Energy Association www.awea.org British Wind Energy Association www.bwea.com Renewable Energy Policy Project www.repp.org/wind/index.html www.windustry.org/

Delphi Method www.is.njit.edu/pubs/delphibook

Noise Measurement www.nonoise.org/library/diction/soundict.htm www.acoustics-noise.com/dBA-B-C-D-U-G-U-AU-tables.shtml www.nonoise.org/library/envnoise/index.htm www.nonoise.org/library/sndbasic/sndbasic.htm www.elaw.org/assets/pdf/noise.pdf www.nonoise.org/hearing/exposure/standardschart.htm www.cdc.gov/niosh/topics/noise/abouthlp/abouthlp.html Noise Pollution by Clifford Richardson Bragdon Noise Pollution The Unquiet Crisis by Clifford Bragdon

Turbine Noise www.ecw.org/ecw/productdetail.jsp?productId=508&numPerPage=100&sortA Longtime measurements of noise from wind turbines. Journal of Sound and Vibration.

Vol 277, Issue 3, 22 Oct 2004 pages 567-572. Martin Björkman www.navcon.com/CaseStudy_12.htm www.hayesmckenzie.co.uk www.kirbymountain.com/rosenlake/wind/

LTU Wind Energy Noise Impact Delphi Survey Dec 3, 2004

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Participant Profile To report a demographic analysis of the study, we need some background information on the participants. Please tell use the about yourself. Name: _____________________________________________________________________________

Address: ___________________________________________ County: _________________________

Phone number:___________________________ Email:______________________________________

Professional title: _____________________________________________________________________

Stakeholder Affiliations (Select all that apply): □ State of Michigan employee. Specify Department ______________________________________________ □ Local zoning board member □ County Commissioner □ Wind Energy Developer (including owners, investors, employees) □ Utilities, electric cooperatives, transmission company □ Farm or land owner □ Renewable Energy Organization (i.e. Next Energy, GLREA, ACORE, etc) □ Environmental Activist. Specify Organization _________________________________________________ □ Consumer’s Organization (i.e., Michigan Farm Bureau, etc.) □ Educator □ Student (circle one: K-12, University) □ Other, Specify: _________________________________________________________________________

Please characterize your knowledge/experience with wind energy: (circle one) No

experience Read a few articles Extensive self

education College degree Professional less

than 5 years Professional more

than 5 years

Please characterize your knowledge/experience with environmental noise assessment: (circle one) No

experience Read a few articles Extensive self

education College degree Professional less

than 5 years Professional more

than 5 years

Have you personally visited a wind farm? Yes No

How did this presentation help you better understand the impact of wind turbine noise?

___________________________________________________________________________________

___________________________________________________________________________________

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On what aspects of wind turbine noise do you plan to conduct further research after today? ___________________________________________________________________________________

___________________________________________________________________________________

___________________________________________________________________________________

Will you participate in a continuing email dialog on this topic?

Yes No

LTU Wind Energy Noise Impact Delphi Survey Dec 3, 2004

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If so, how many times per week will you participate in the email dialog?____________________________ What additional information would you like to see presented on wind turbine noise? ___________________________________________________________________________________

___________________________________________________________________________________

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In which additional wind energy Delphi Inquiries would you be willing to participate? □ Wind turbine impact on wildlife □ Interference with electronic tower transmission □ Land requirements for service roads and power stations □ Impact on viewsheds □ Decommissioning Issues

Noise Impact Questions Please answer the following questions as best you can. Keep in mind that 1). The questions refer to the noise exposure of residents on properties near a commercial wind farm. 2. We are helping to develop wind turbine noise guidelines for the State of Michigan which can be used by as a model ordinance most local communities. Feel free to share opinions with other participants while selecting your answers.

1. The siting guidelines should specify that the loudness of frequencies between 20 Hz – 20kHz (normal hearing) be measured on which scale?

A B C D G

2. Should low frequency noise (20-250 Hz) requirements be specified separately?

Yes No

3. If you answered yes to question 2, on which scale low-frequency requirements be measured?

A B C D G

4. Should infranoise (< 20 Hz) requirements be specified separately?

Yes No

5. If you answered yes to question 4, on which scale infrasound requirements be measured?

A B C D G

LTU Wind Energy Noise Impact Delphi Survey Dec 3, 2004

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6. If turbines are placed on a farm where someone resides, where should the noise impact be measured?

outside dwelling on same property

Inside dwelling on same property

Property line Outside neighboring dwelling

Inside neighboring dwelling

7. Siting guidelines should specify the following maximum dB during the day for frequencies between 20 Hz and 20 kHz:

40 dB 45 dB 50 dB 55 dB 60 dB

8. If ambient noise (such as noise from the wind) during the day becomes higher than the specified limits, the limits should be adjusted by:

None 3 dB 5 dB 6 dB 10 dB

9. Should the maximum turbine noise allowed during the day be based on any of the following indices?

Lmax (Maximum volume) Yes No

L10 (annoyance) Yes No

Leq (average sound energy) Yes No

L90 (background noise Yes No

Ldn (day-night average) Yes No

Speech Interference Level (SIL) Yes No

10. If you answered ‘yes’ to specifying a Speech Interference Level, on what distance should this be based?

1/2 ft 1 ft 3 ft 6 ft 10 ft

11. Should sound levels at night be specified as adjustments to day values or absolute values?

Adjustments Absolute values

12. If you selected absolute values for question 11, what should the siting guidelines should specify as the maximum dB during the night for frequencies between 20 Hz and 20 kHz?

40 dB 45 dB 50 dB 55 dB 60 dB

13. Should wind turbine siting guidelines specify a maximum number of starts and stops during the night?

Yes No

LTU Wind Energy Noise Impact Delphi Survey Dec 3, 2004

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14. Siting Guidelines should specify penalties when noise exceeds the limit for more than:

5 min 20 min 30 min 45 min 1 hr No penalty

15. Do you have first-hand experience with the following ? □ ASTM E 1240 “Standard Test Method for Performance Testing of Wind Energy Conversion Systems”

□ ICE 614000-11 Wind Energy Standards: Acoustic Emission Measurement Techniques

□ ISO 1996 “Description and Measurement of Environmental Noise”

□ EPA Model Noise Ordinance

□ Other: ________________________________________________________________________________

16. If you checked one or more the standards in Question 15, Would you recommend that wind turbine siting guidelines specify using these standards? □ ASTM E 1240 Yes No

□ ICE 614000-11 Wind Yes No

□ ISO 1996 Yes No

□ EPA Model Noise Ordinance Yes No

□ Other Yes No

Please state why: ____________________________________________________________________

Are there any additional questions you think need to be addressed?

___________________________________________________________________________________

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