assessment of low‐frequency noise from wind turbines in maastricht

7/31/2019 Assessment of lowfrequency noise from wind turbines in Maastricht

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Assessmentoflowfrequencynoise

fromwindturbinesinMaastricht1

ByHenrikMller*,Steffen Pedersen *,JanKlosterStaunstrup **andChristianSejerPedersen**Section ofAcous tics ,**DepartmentofDevelopmentandPlanning, Aa lborgUniversity, Denmark

1 PrefaceThenoisefromaplannedwindfarmprojectatLanakerveldinMaastrichthasbeenevaluatedinseveralreports.BoukichandKoppen

1studiedalternativeprojects,andKoppen

2madeadditionalanalysesincluding

analysesoflowfrequencynoise.Koppen3analyzedtheoptimizedandselectedprojectcomprisingfour

VestasV1123.0MWturbineswith119meterhubheight.Aspecialanalysisoflowfrequencynoiseinthe

selectedprojectwasmadebyKoppen4.Uponrequestfromlocalresidents,anadditionalanalysisoflow

frequencynoisewasmadebyKoppen5takingintoaccountinformationgiveninanarticlebyMllerand

Pedersen6aswellasnewregulationsoflowfrequencynoisefromwindturbinesinDenmark

7.

Subsequently,theCityCouncilofMaastrichthasrequestedthepresentreportinparticularaddressing

certainquestions.Unfortunately,onlythelatestDutchreport5wasmadeavailableinEnglish,but

employeesoftheCityCouncilandArcadisNederlandBVhavebeenveryhelpfulansweringquestions.In

addition,wehaveusedoriginalnoisemeasurements8anddatasheets

9,10.

Thereportispublicandmayberedistributedasawhole.

2 IntroductionAbriefintroductiontolowfrequencysoundisrelevant.

Soundandnoisecanbecharacterizedbytheirfrequency.Therangefrom20Hzto20kHz(20cyclesper

secondto20,000cyclespersecond)isusuallycalledthenormalhearingrangeortheaudiofrequencyrange.Soundwithfrequenciesabove20kHzisdenotedultrasoundandcannotbeheardbyhumans.

Soundwithfrequenciesbelow20Hzisdenotedinfrasound.Itisusuallyunderstoodthatalsoinfrasound

cannotbeheard,butthisiswrong.Infrasoundisaudibleatleastdownto1or2Hz,providedthatthesound

pressurelevelissufficientlyhigh.Thesoundisperceivedwiththeears,usuallygivingafeelingofpressure

attheeardrums.

The20200Hzrangeisdenotedthelowfrequencyrange.Slightlydifferentlimitsaresometimesused,e.g.

10160Hz.

1PreparedfortheCityCouncilofMaastricht,ISBN9788792328823,AalborgUniversity,10.April2012.


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Everyoneknowsfromhiseverydaysurroundingstheperceptionofhearingsoundatlowandinfrasonic

frequencies.Typicallowfrequencysoundsourcesareventilationsystems,compressors,idlingtrucksand

theneighborsstereo.Infrasoundatanaudiblelevelisusuallyfoundonthecardeckofaferryandwhen

drivingacarwithanopenwindow.However,infrasoundismostoftenaccompaniedbysoundatother

frequencies,sotheexperienceoflisteningtopureinfrasoundisnotcommon.

Forathoroughreviewofthehumanhearingatlowandinfrasonicfrequencies,seeMllerandPedersen11.

Theleveloftheinfrasoundproducedbymodernwindturbinesissolowthatthesoundcannotbe

perceivedbyhumansevenclosetotheturbines6.Muchhigherlevelsoccurelsewhereinourdaily

environment,e.g.intransportation.

Lowfrequencywindturbinenoiseisusuallydescribedashummingorrumbling.Itmayhaveamoreorless

pronouncedtonalcharacter,e.g.intermsoftonesthatfluctuateandvaryinleveland/orpitch,oroftone

like

pulses

excited

with

regular

or

random

intervals.

The

feeling

of

pressure

at

the

eardrums

is

also

reported.Itischaracteristicthatthenoisevariesalotintimeandwithwindandotheratmospheric

conditions.

Therateofmodulationofthelowfrequencynoisefromwindturbines(andhigherfrequenciesaswell)is

oftenintheinfrasonicfrequencyrange,e.g.thebladepassagefrequency,andthenoisemaythusbe

mistakenasinfrasound,evenwhenthereislittleorvirtuallynoinfrasoundpresent.

3 SpecificquestionsThequestionsaskedbytheCityCouncilareconsideredineachtheirsubsection.Thefulllistisgivenin

AnnexA.

3.1 EffectsofLowFrequencyNoisehavebeenresearchedalot.Onwhichaspectsdoestheresearch(approach)ofMllerandPedersendifferfromthatofother

researchers?

Itistruethatmanyinvestigationshavestudiedeffectsoflowfrequencynoiseingeneral.However,only

fewstudieshaveaddressedlowfrequencynoisefromwindturbinesspecifically.

MllerandPedersen6didnotinvestigateeffectsoflowfrequencynoisebutfocusedonthephysicalnoise

from

wind

turbines,

such

as

emitted

sound

power,

its

frequency

distribution,

propagation

to

neighbors

and

transmissionintoneighborhouses.

TheapproachofMllerandPedersendoesnotdifferfromthatofotherresearchers.Mostmeasurements

weremadeaccordingtointernationalstandards,andconventionalstatisticalmethodswereusedinthe

analyses.Possibleannoyancefromlowfrequencynoisewasevaluatedfromitsaudibilityandcontribution

tothetotalnoiseaswellasstandardcriteriausedforothernoisesources.

TheinvestigationreportedbyMllerandPedersenwastoourknowledgethefirststudyfocusingonthe

relationshipbetweenlowfrequencynoiseandturbinesize.Themeasurementsweremadebythe

consultancycompanyDelta,whopublishedthedatainunreviewedprojectreportsbySndergaardand

Madsen12,13,14andHoffmeyerandSndergaard15.MadsenandPedersen16addedemissiondatafrom17


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newturbinesof1.8to3.6MW.TheaddeddatawereincludedinanupdatedreportbyMlleretal.17with

essentiallythesameresultsandconclusionsasthosebyMllerandPedersen6howeverbasedonalarger

material.

DifferencesdoexistbetweentheresultsbyDeltaandbyus,buttheyaremainlymoderate.SomeofDeltas

findingsarenotclearlyreflectedintheirconclusions,though.Largerdifferencesexistbetweentheresults

andtheinterpretationsgiveninpressreleasesfromDelta,TheDanishEnvironmentalProtectionAgency

(EPA)andthewindpowerindustry,whichmightbeclaimedtounderratesomeofthefindingsandpossible

adverseeffectsofwindturbinenoise.

AtthisplaceitisrelevanttomentionthatMllerandPedersenalsoanalyzedDutchmeasurementsofwind

turbinenoiseoriginallypublishedbyvandenBergetal.18.Virtuallythesamelevelsandthesame

differencesbetweensmallandlargeturbineswerefoundasintheDanishmeasurements.

It

is

recommended

that

readers

make

themselves

acquainted

with

our

original

publications

6,17

.

3.2 WhatarethemaineffectsofLowFrequencyNoise(LFN)onhumansandwhenspecificallydotheseeffectsoccur?

Noisewithprominentlowfrequencycomponentsmayaffecthumanhealthandwellbeingtoalarger

extentthannoisewithoutsuchcomponents.

Atlowfrequencies,theloudnessincreasesmoresteeplyabovethehearingthresholdthanathigher

frequencies(seee.g.Whittleetal.19,MllerandAndresen

20,Bellmannetal.

21,ISO226

22).Thus,asound

moderatelyabovethresholdmaybeperceivednotonlyloudbutalsoannoying(AndresenandMller23,

Mller24,Inukaietal.

25,Subedietal.

26).Sincethereisanaturalspreadinhearingthresholdsbetween

individuals,alowfrequencysoundthatisinaudibleorsofttosomepeoplemaybeloudandannoyingto

others.

Lowfrequencysoundisparticularlyannoying,whenitoccursaloneorwithlowlevelsofsoundathigher

frequencies.Thismeansthatitisusuallymoreannoyingindoorsthanoutdoors,sincethehighfrequencies

aremoreattenuatedbythesoundinsulationofthehousethanthelowfrequenciesare.Alsoitisoften

moreannoyingintheeveningandatnight,whenitisotherwisequiet.

Prolongedexposuretoaudiblelowfrequencysoundmaycausefatigue,headache,impairedconcentration,

sleepdisturbanceandphysiologicalstressasindicatedbyincreasedlevelsofsalivacortisol(see.e.g.

Berglundetal.27,Bengtssonetal.

28,Wayeetal.

29,Wayeetal.

30).

Thereisnoreliableevidenceofphysiologicalorpsychologicaleffectsfrominfrasoundorlowfrequency

soundbelowthehearingthreshold(seee.g.BerglundandLindvall31).

(TheaboveparagraphsarepartlyquotedfromBolinetal.

32andMllerandPedersen

11).


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3.3 TheDanishGovernmenthaschangedtheregulationsforerectingwindturbinesasaresultofyourresearch.Isthatcorrect?Andifso,whatspecificchangeshave

beenmade?

TheDanishregulationsaregiveninastatutoryorderonnoisefromwindturbines7

.Theorderwasupdatedin2011toincludespecificrulesforthelowfrequencypartofthenoise(beingeffectiveby1.January2012).

3.3.1 BackgroundAtthepreviousrevisionofthestatutoryorderonwindturbinenoisein2006,theDanishEPAstatedthat

regulationoflowfrequencywindturbinenoisewouldnotbeneeded,becausethegeneral20dBindoor

limitappliedtoothersourceswouldautomaticallybecompliedwith,whenthenormaloutdoornoiselimits

wereobserved.

Infact,theEPAsowndatashowedtheopposite33,andduringthefollowingyears,anincreasingpressure

wasputontheEPAfromneighbors,whocomplainedaboutlowfrequencynoisefromwindturbines.

Moreover,scientificresultssupportedtheneedforregulation,mostrecentlythepublicationsfromDelta16

andAalborgUniversity6,17

.

InOctober2010,areportfromAalborgUniversityrevealedseriouserrorsinthenoisesectionsofthe

EnvironmentalImpactAssessment(EIA)foraprestigiousDanishtestcenterforlargewindturbines34.The

lawestablishingthecenterhadtoberevised,andthehandlingofnoisefromwindturbinesintheEPA

attractedpoliticalattentioninParliament.TheMinisteroftheEnvironmentpromisedtointroducelimitsfor

lowfrequencywindturbinenoise.

3.3.2 LowfrequencylimitThegeneral(i.e.notforwindturbines)DanishlimitforlowfrequencynoiseindwellingsisanindoorA

weightedsoundpressurelevelof20dB(eveningandnight)and25dB(day).Onlyfrequenciesinthe10160

Hzfrequencyrange(thirdoctavefrequencies)areincluded.Thelevelismeasuredasthepoweraverageof

thelevelsinthreepositions,ofwhichtwoareinthelivingareasoftheroom,wherethenoisecomplainant

perceivesthenoiseasparticularlyloud.Thethirdpositionisneararoomcorner(11.5mheight,0.51m

fromthewalls).Duetothepoweraveragingprocess,thefinalresultisclosetothelevelintheappointed

highlevelpositions.

Withtheupdatedorder,the20dBlimitappliesalsoforwindturbinesatwindspeedsof6and8m/s(wind

turbinesrunaroundtheclock).

Unlikeforothernoisesources,thelowfrequencynoiseisnotmeasuredbutcalculatedfrommeasurements

closetotheturbineoftheemittedsound.

TheindoorsoundpressurelevelLpAiscalculatedusingthefollowingequation:

agrefWA,pA dB11m1

logdB20 LLL

dLL

10

LWA,refistheapparentsoundpowerlevelinthereferencedirection,basicallymeasuredaccordingtoIEC

614001135,dthedistancefromthenacelletotheneighbor,Lgcorrectionforthegroundreflection,La


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theairabsorptionequaltoad,whereaistheabsorptioncoefficient,andLthesoundinsulation.Lg,a

andLaregiveninatablequotedhereasTable1.

Table1.ConstantsusedintheDanishregulationforcalculatingindoorlowfrequencynoiseLpA,LF.

Frequency

(Hz)10 12.5 16 20 25 31.5 40 50 63 80 100 125 160

gL (land)

(dB)6.0 6.0 5.8 5.6 5.4 5.2 5.0 4.7 4.3 3.7 3.0 1.8 0.0

gL (sea)

(dB)6.0 6.0 6.0 6.0 6.0 5.9 5.9 5.8 5.7 5.5 5.2 4.7 4.0

L

(dB)4.9 5.9 4.6 6.6 8.4 10.8 11.4 13.0 16.6 19.7 21.2 20.2 21.2

a (dB/km) 0 0 0 0 0.02 0.03 0.05 0.07 0.11 0.17 0.26 0.38 0.55

Calculationsaremadeforthethirdoctavefrequencybands10160Hzandthelevelssummarizedtogive

theAweightedlowfrequencysoundpressurelevelLpA,LF.

3.3.3 CommentstothelowfrequencyregulationBasedontheexistingknowledgeoftheeffectsoflowfrequencynoiseonhumans,weconsiderthechosen

limitof20dBfortheAweightedlevelofthe10160Hzfrequencyrangeasareasonablelimit.

InthenewDanishstatutoryorderforwindturbines,thenoiseisnotmeasuredbutcalculated.Thisneed

not

be

a

problem,

if

the

calculations

are

correct.

But

they

are

not.

Themainproblemisthesoundinsulationtabledinthestatutoryorder.Thevaluesarebasedon

measurementsin26DanishhousespublishedbyHoffmeyerandJakobsen36.Unfortunately,these

measurementswerewrong.

Theissueisthatsoundatlowfrequenciesvarieswithinaroomusuallybymanydecibelsandas

mentionedinSection3.3.2,thelevelshouldbrieflyexplainedbemeasured,wheretheannoyedperson

findsitloudest.Thesoundinsulationmustbemeasuredthesamewayinordertobeapplicablefor

calculationsofrelevantindoorlevelsfromoutdoorlevels.Butitwasnot.Theindoormeasurementswere

simplymadeatarbitrarypositionsthatwerenotselectedforahighlevel.Thustheobtainedvaluesof

soundinsulationaretoohigh.

Figure1showsanexampleofthesounddistributioninaroom.Eachframeshowsthesounddistributionin

agivenheight,andthecolorscalegivesthesoundpressurelevel(scaleattheright).


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Figure1.Exampleofsimulatedsounddistributioninaroom(5.0mx3.6mx2.5m;LxWxH).The

soundisa112Hzpuretone.Thesoundentersthrougha90cmx90cmopening(assumedwindow)at

theleft

end

wall.

Probably

as

asurprise

to

many,

this

is

not

where

the

highest

levels

are

found,

which

isatthelowersidewall.

Asseen,therearelargeareaswithsoundpressurelevelsofmorethan25dB,whilelessthan10dBmaybe

measuredinotherareas.Thefigureappliestoanextremesituationwithapuretoneinanemptyroom,but

variationsof30dBwithpuretonesand20dBwiththirdoctavebandnoisearenotuncommoninreal

furnishedrooms.

TogetherwithaSwedishcolleague,wepointedouttheerrorinHoffmeyerandJakobsensdata36ina

commentary37

inthescientificjournalwherethemeasurementswerepublished.

Inareply38tothecommentary,DanishEPAemployeeJakobsenseemstobeoftheopinionthatitmakesno

difference,whetherthemeasurementsaremadeintheloudestareasornot.Thisisobviouslywrong.The

firstauthorHoffmeyeroftheoriginalpublicationdidnotsignthereply,anddespiteofmanyrequestsithas

notbeenpossibletoclarify,whetherhesharestheviewsexpressedinJakobsensreply.

Basedontheirmeasurements,HoffmeyerandJakobsen36proposedsoundinsulationdatatobeusedfor

calculationofindoorlowfrequencynoisefromwindturbines.Duetothemeasurementerror,thesevalues

aretoohigh.FortheDanishregulation,valueswereincreasedevenfurtherby2.24.1dBdependingon

frequency.

Height: 0.05 m Height: 0.35 m Height: 0.65 m



dB

5

10

15

20

25

30

35


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Asaresult,thecalculationoftheDanishregulationgivesvaluesthatunderestimatethelowfrequency

noisethatwouldbemeasuredinneighboringhouses.

Themagnitudeoftheerrorisestimatedtobearound5dB,seeAnnexB.

Evenwhenanerrorof5dBmightseemsmall,itisfarfrombeingnegligible.AsmentionedinSection3.2,

theloudnessandannoyanceincreasemoresteeplyabovethresholdthanathigherfrequencies.Thismeans

thatwhenthelevelisafewdecibelsabovethe20dBlimit,theconsequencesaremoresevere,thanifa

limitathigherfrequenciesisexceededbythesameamount.Mostpeoplewillhearasoundat20dB,and

somewillfinditannoying.Fewpeoplewouldprobablyaccept25dBintheirhomeatnightandhardly

anyonewouldaccept30dB.

Intheargumentationforthenewregulation,theEPAsays:TheDanishEPAfindsthattherewillbea

substantialnoisenuisance,ifthelowfrequencyindoornoiseexceeds20dBintheeveningandnight.The

perceived

annoyance

from

low

frequency

noise

increases

strongly,

when

the

noise

reaches

above

20

dB.

39

(Ourtranslation).

3.3.4 LimitsforthegeneralnoiseTocompletethedescriptionoftheDanishregulation,calculationsandlimitsfortotalnoiseshouldbe

brieflymentioned.

Thelimitsfortotalwindturbinenoisewerenotmodifiedintheupdate.ThelimitsareoutdoorAweighted

levelsof39dBinresidentialareasexceptforresidencesintheopencountryside,wherethelimitis44dB.

Theselimitsapplyatawindspeedof8m/sataheightof10m.Atawindspeedof6m/s,limitsof37and

42dBapply,respectively.Thelowsetoflimitsalsoappliestorecreationalareasandareasforvarious

institutions.

Unlikeforothernoisesources,thenoiseisnotmeasuredatneighboringdwellings,butmeasurementsclose

totheturbinesoftheemittedsoundareusedtocalculatetheoreticaloutdoorsoundpressurelevelsatthe

neighbors.

Thenoiseiscalculatedusingthesameformulaasfortheindoorlowfrequencynoise,exceptthatthesound

insulationLisomitted.1.5dBisusedforthegroundreflectionL(3.0dBoversea),andabsorption

coefficientsaforthefullfrequencyrangearegiveninatablequotedhereasTable2.

Table2.AbsorptioncoefficientsusedintheDanishregulationforcalculatingoutdoortotalsound

pressurelevelLpA.

Frequency

(Hz)50 63 80 100 125 160 200 250 315 400 500 630

a

(dB/km)0.07 0.11 0.17 0.26 0.38 0.55 0.77 1.02 1.3 1.6 2.0 2.4

Frequency

(Hz)800 1000 1250 1600 2000 2500 3150 4000 5000 6300 8000 10000

a

(dB/km)2.9 3.6 4.6 6.3 8.8 12.6 18.8 29.0 43.7 67.2 105 157


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3.4 RegardingtheArcadisReport,havethecalculationsandassessmentofLowFrequencyNoisebeenmadecorrectlywithrespecttotheDanishmethodand

standards?Ifnot,inwhatrespectdotheydiffer?Willrecalculationleadto

substantiallydifferentresults?

WehavethefollowingcommentstotheArcadisreport5.

Table2ofthereporthasadatapointfortherelativespectrumat20Hz,whichisreportedtobefromthe

articlebyMllerandPedersen6(TableIII).However,ourarticledoesnothavedataatthisfrequency.Inthe

otherendofthelowfrequencyrange,forsomeoddreason,Table2doesnotincludethefrequencies125

and160Hz.

Likewise,inthecalculations,Arcadisuseddatapointsat10,12.5,16and20Hzallegedlyfromourarticle,

wheredatapointsdonotexistatthesefrequencies.Furthermore,thedatapointat20Hzusedinthe

calculationsisnotthesameasgiveninTable2.

However,theextradatapointshavebeengivenreasonablevalues,andsincethenoiseattheselowest

frequenciesdoesnotcontributemuchtothetotallowfrequencylevel,theirexactvaluehasonlymarginal

impactonthefinalresult.Nevertheless,theadditionofdatapointstotheMllerandPedersendata

should,ofcourse,havebeenexplainedanddiscussedintheArcadisreport.

Exceptforthis,theunderstandinganduseoftheMllerandPedersendataarecorrect.

AlsotheunderstandinganduseoftheDanishregulationforlowfrequencynoisearecorrect.Wehave

checkedthecalculationsoflowfrequencynoiseatthefourselectedneighborpositionsandgetthesame

results.

Itshouldbenotedthatthe20dBlimitwasactuallyexceededinthreeofthefourcalculatedpositionsinall

scenariosandinallfourpositionsinonescenario,whichisnotfullyreflectedinTable3,wherefiguresare

roundedtonearestintegerdecibel.InDenmark,thelimitisanabsolutelimit,whichmaynotbeexceeded.

Arcadisseemstobeunawareofthemeasurementerrorintheinsulationmeasurementsbehindthedataof

theDanishstatutoryorder.Despitethatthishasbeenpointedoutinthescientificliterature,itmaybe

consideredexcusable,sincetheorderitselfdoesnotinformabouttheoriginofthedata.

3.5 Inyouropinion,isthenoisespectrumreferredtoasArcadisacousticstudyinTables1and2arealisticworstcasescenarioforcalculatingLFNeffectsproduced

by3MWwindturbines?Ifnot,whynotandcanyouindicatewhatthecorrect

assumptionswillbe?Willthisleadtosubstantiallydifferentresults?

No,thespectrumoftheoriginalArcadisstudyinthesetables(Koppen5,firstrowsofTable1and2)does

notrepresentaworstcasescenario.Itmaybesofortherelativesourcelevelatcertainfrequencies,but

notforallfrequencies,andnotforthefinalresult,thenoiseattheneighbors.


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WedonotknowtheexactderivationoftheArcadisrelativespectrumfromthenontranslatedprevious

Dutchreports(Koppen2,4),butworstcaseaspectshavenotbeeninvolvedinthederivationofthetwoother

relativespectra,andthefinalresultsofusingthethreesetsofdataareverysimilar(Koppen5,Table3).

ThedatabyMllerandPedersen6areestimatesbasedonmeasurementsofturbinesofvarioussizeand

models.Themodelisabestfitmodeloftheactuallymeasureddatawithoutadditionstoaccountfor

uncertaintyandvariationbetweenturbines.

Furthermore,theaveragingbyMllerandPedersendisguisestonesortonelikecomponentsthattypically

appearinsinglefrequencybandsforaspecificmodel,butindifferentbandsfordifferentmodels.Dueto

roomresonances,suchtonalortonelikenoisecomponentsmaybeparticularlyloudandannoyingin

certainhousesand/orrooms.

Thereisanunavoidablevariationinnoiseemissionbetweenturbines,evenofthesamemodel.The

probability

that

a

given

delivered

turbine

emits

more

noise

than

an

average

turbine

or

for

that

matter,

anyrandomlychosenmeasuredturbineofthesamemodel,isinprinciple50%.

Forplanningpurposes,thenoiseemissionshouldthereforebespecifiedaccordingtoIECTS114001440.

Thisdocumentusesmeasurementsonseveralsimilarturbinesandtakesintoaccountthevariation

betweenturbinestoobtainthedeclaredapparentsoundpowerlevelLWdforthemodel.Thisisthelevelof

theapparentsoundpowerthatwillonlybeexceededby5%oftheproduction.Usingsuchvalueswould

yieldascenario,whichcouldreasonablywellbedenotedasworstcase.

TheVestasV112scenarioofTables3isindeedderivedfrommeasurementsonasingleturbine8.Even

whenthelevelshavebeenmarginallyadjustedtomeetthespecifiedtotalnoiseinVestasdatasheet9,this

doesnotmakeitaworstcasescenario.VestasdoesnotrefertoIECTS1140014orotherwiseclaimor

documentthattheirvaluesarethemaximumemittedsoundpowerforsamplesoftheproduction.When

seenacrossthemeasuredwindspeeds,theirdatasheetvaluesareinfactclosetothemeasuredlevelsfor

thesinglemeasuredturbine.(SeealsoSection4.1).

Howmuchhighervalueswillbeinaworstcasescenario,dependsonthevariationbetweenturbines,and

sincethisisnotspecifiedfortheactualmodel,wecanonlygivegeneralinformation.Mlleretal.17

estimatedavalueof2.64.8dBtobeaddedtotheaverageofturbinestoachievelevelsaccordingtoIECTS

1140014.Partofthisvariation,maythoughstemfromdifferencesbetweensimilarturbinesrunningin

differentmodes,amatterwhichwasnotfullyexpoundedinthedataatourdisposal.Onlyturbine

producershavethefullinformationonturbinesettingsandshouldprovidetheinformation,e.g.byusing

IECTS1140014.Thevaluesmentionedapplytothetotalnoiseandnotparticularlytothelowfrequency

noise.

ExperiencefromarecentDanishprojectwitheightVestasV903.0MWturbineshasshownthatthe

measuredsoundpowerlevels41exceedtheanticipatedlevelsfromtheEnvironmentalImpactAssessment

(EIA)42,andseveralturbinesnowruninnoisereducedmodestofulfillnoiserequirements.Theturbines

werebuiltbeforethenewDanishregulations,butthemeasurementsshowthattheyfulfillthenewlow

frequencyrequirements43.Nevertheless,thereareheavycomplaintsfromneighbors,anditisour

impressionthathighemissionsinthe50Hzthirdoctavebandareofimportance.Thenearestneighboris

545metersfromtheclosestturbine.ThedatasheetnoisespecificationsfortheV903MWturbine44are


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veryclosetothoseoftheV1123MW,althoughmarginallylowerformostwindspeeds.Itshouldbe

emphasizedthatwehavenoreasontobelievethatsuchproblemsarespecifictoVestasturbines.

ThesourcedatausedbyArcadisfortheVestasV112scenario(Koppen5,Table3thirdrow),i.e.relative

spectrumlevelsfromthemeasurementsoftheV1123.0MWturbineappliedtodatasheetvaluesforthe

totalnoiseofV112andV80turbines,canbeconsideredrealisticandlikely.

Thesedatawillthereforebeusedforcalculationsintheremainingpartofthisreport.SincetheArcadis

reportonlydisplaysvaluesupto160Hz,valuesforthefullfrequencyrangearegiveninAnnex3.Datafor

theV112turbinearealsogiveningraphicalforminFigure2.

Figure2.ThirdoctaveapparentsoundpowerlevelsforVestasV1123.0MWturbinesusedinthe

calculations.

Itisnotedthattherearepeaksat63and100Hz,suggestingtonesortonelikenoiseinthesefrequency

bands.

Itshouldbeemphasizedthatallcalculationsofnoiseattheneighborsinthisreportincludenoisefromthe

proposednewturbinesaswellastheexistingBelgianturbines.

5055

60

65

70

75

80

85

90

95

100

105

10

12.

516

20

25

31.

540

50

63

80

100

125

160

200

250

315

400

500

630

800

1000

1250

1600

2000

2500

3150

4000

5000

6300

8000

10000

dB

Thirdoctavefrequency(Hz)


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11

3.6 IsitpossibletoindicatetheexpectedLFNthatwillbeproducedbytheplannedfourwindturbinesoftypeVestasV1123MW,hubheight119m.

Itispossibletoindicatearealisticandlikely(notworstcase)scenarioforthelowfrequencynoiseexposure

attheneighbors.

Forthatpurpose,sourcedataexplainedinSection3.5andshowninFigure2andAnnexCareused.Forthe

soundtransmission,theDanishregulation7(Section3.3.2)isusedandresultsarecorrectedwiththe

estimated5dBerrorduetothesoundinsulationmeasurementerror(Section3.3.3andAnnexB).

Becauseofdifferencesinsoundinsulation,notallhouseswillhavethesameindoornoise,andhigher

soundpressurelevelsthancalculatedwillbeobservedinsomehouses.Itistheexpressedobjectiveofthe

Danishregulationthathigherlevelswillbeobservedin33%ofthehouses39.HoffmeyerandJakobsen

36had

otherwiseproposedthatthecalculatedlevelshouldonlybeexceededin1020%ofthehouses.Inthe

following,calculationshavealsobeenmadewiththeirproposedsoundinsulationdata(resultslikewise

correctedbytheestimated5dBmeasurementerror).

Thesecalculationsofferacredibleestimateoftheindoorlowfrequencynoisetobeexceededinthe33%

respectively1020%poorestsoundinsulatedhouses.Thecalculationsdonotaccountfordeviationsinthe

noiseemittedfromtheactuallyerectedturbines(Section3.6)(includingtheirdirectionalpattern),

deviationsintheemittedsoundfromtheexistingBelgianturbines(includingtheirdirectionalpattern),

differencesinbuildingstyleandsoundinsulationbetweenDutchandDanishhouses,possiblyopen

windowsandvariationinatmosphericconditions.

Table3givescalculatedoutdoorandindoorlevelsforthefourneighborpositionschosenbyArcadis5.

Table3.Calculatedoutdoorandindoorsoundpressurelevelsatselectedneighborpositions.The

indoordataarelevelsexceededinthe33%respectively1020%poorestsoundinsulatedhouses.

Windspeed8m/s.

Neighborposition OutdoorLpA(dB) IndoorLpALF(dB)

DanishregulationHoffmeyerand

Jakobsen

7:

newhomesMalberg45.1 25.3 28.1

7B:Toustruwe,Malberg

44.0 24.4 27.2

17:

Kantoorweg45.2 25.2 27.9

18:

Europark,Belgium46.2 26.1 28.9

correctedwiththeestimated5dBerrorduetothesoundinsulationmeasurementerror

(Section3.3.3andAnnexB)


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12

Itisseenthat,dependingonposition,outdoorlevelsof44.046.2dBareexpected.Fortheindoorlow

frequencynoise,levelsof24.426.1dBormoreareexpectedin33%ofhouses(columnDanishregulation)

and27.228.9dBormorein1020%ofhouses(columnHoffmeyerandJakobsen).

Togiveanideaofhowfarawaythe20dBindoorlimitisexceeded,20dBnoisecontoursfortheindoor

lowfrequencynoisehavebeencalculated.Thecontoursareshownonanopenstreetmap(Figure3)and

onanortophoto(Figure4)(MicrosoftBingAerial).

Thecontourscanalsobeseenonline,whereitispossibletoswitchbetweenmapandaerialview,andto

zoomandmovearoundwiththecursor.Itisalsopossibletousestreetviewande.g.seetheexisting

Belgianturbinesindifferentperspectives.Internetaddress:http://tinyurl.com/d7ht7xh.

Itisseenthatthe20dBlimitwillbeexceededinaverylargeareawithmanydwellingsandnotonlyatthe

nearestneighbors.Itshouldberememberedthattheloudnessincreasesmoresteeplyabovethehearing

threshold

than

at

higher

frequencies

as

mentioned

in

Section

3.2,

and

that

The

perceived

annoyance

from

lowfrequencynoiseincreasesstronglywhenthenoisereachesabove20dB(quotefromDanishEPA39as

mentionedinSection3.3.3).


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13

Figure3.Contourswherethe20dBindoorlowfrequencylimitisexceededinthe33%or1020%

poorestsoundinsulatedhouses(redandorangeline,respectively).Windspeed8m/s.Seetextfor

calculationdetails.


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14

Figure4.Contourswherethe20dBindoorlowfrequencylimitisexceededinthe33%or1020%

poorestsoundinsulatedhouses(redandorangelines,respectively).Windspeed8m/s.Seetextfor

calculationdetails.


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15

4 GeneralcommentstotheprojectAllquestionsasked(AnnexA)andthustheprecedingsectionshavedealtwithlowfrequencynoise.

However,wefinditappropriatetoaddsomegeneralcomments.

4.1 TotalnoiseoutdoorsTheDutchnoiselimitsforwindturbinenoise

45,46arebasedonthedayeveningnightconcept,Lden,thelong

term(yearly)equivalentlevel,wherenoiseintheeveningisgivenapenaltyof5dBandnoiseinthenighta

penaltyof10dB.Thisconceptwasdevelopedtoallowtrafficnoisewithatypical24hourpatterntobe

characterizedbyasinglefigure.However,suchdiurnalpatterndoesnotexistforwindturbines,sincewind

turbinesrunaroundtheclock,andwedonotfinditsuitabletocharacterizewindturbinenoisebyLden.Also

Pedersen47arguedagainstusingofLdenforwindturbinenoise.

Sincemostcomplaintsrelatetothewindturbinenoiseintheeveningandatnight,weappreciatethat

there

is

an

additional

Dutch

limit

for

the

level

at

night

Lnight.

However,

this

limit

also

applies

to

a

yearly

average,whichallowsmorenoiseatsomenights,ifthereislessnoiseatothernights.Thisisnottheway

thehumanorganismworks,though.Ifwearedisturbedbynoiseinthenight,wecannottakeadvantageof

thefactthat,afterawhiletomorrow,aftersomedays,maybeaweektherewillbenightswithlessor

nonoise.Itisourconvictionthatlimitsshouldapplytotheactualnoiseinsituationsthatoccurregularly.

InDenmarkandSweden,noiselimitsapplytocalculatednoiselevelsatawindspeedof8m/s(10m

height).(InDenmarkadditionallowerlimitsexistat6m/s).Windat8m/soccurslessoftenintheactual

areaaroundMaastrichtthaninmostpartsofDenmark,thusthereareargumentsforusingthenoise

emissionatalowerwindspeedthan8m/s,e.g.6m/s.However,withtheproposedturbines(largerotor,

high

tower),

it

makes

only

a

marginal

difference,

in

fact

the

measured

noise

at

7

m/s

was

higher

than

at

8

m/s8.Figure5showstheemittednoiseasafunctionofwindspeedasmeasuredbyDelta

8andasgivenin

thedatasheet9.Atlowwindspeeds,upto1.2dBmorewasmeasuredthangiveninthedatasheet,while

upto1.4dBlesswasmeasuredathighwindspeeds.


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16

Figure5.ApparentsoundpowerlevelLWAasafunctionofwindspeedasmeasuredbyDelta8andas

givenindatasheetbyVestas9.

Further,thethreemostacknowledgeddoseresponsecurves,includingDutchcurves,havebeenmadewith

calculatednoiseata10mheightwindspeedof8m/sastheindependentvariable(PedersenandWaye48;

PedersenandWaye49;vandenBergetal.

18andPedersenetal.

50).Wehavethereforechosentocalculate

thenoiseforawindspeedof8m/s.

AsmentionedinSection3.3.4,thelimitsinDenmarkat8m/sare39dBindwellingareasand44dBat

dwellingsintheopenland.InSweden,generallimitsare40dBatdwellings,however35dBinareaswith

lowbackgroundnoise51.Theprojectareaisclaimedtobealreadymarkedbyindustry,whicharguesfor

usingtheslightlyhigherDutchnightlimitof41dBwithcalculatedlevelsat8m/s.Doseresponsecurves

indicate2324%rather/fairlyorveryannoyedat41dBcalculatedlevelat8m/s(interpolatedfrom

Pedersenetal.50,Figure2).

Contoursof39,41and44dBatawindspeedof8m/shavebeencalculatedusingthepropagation

calculationoftheDanishregulations.Resultsareshownonanopenstreetmap(Figure6)andonan

orthophoto(Figure7)(MicrosoftBingAerial).(SourcespectraasdescribedinSection3.5andgivenin

AnnexC).

Alsothesecontourscanbeseenonline.Internetaddress:http://tinyurl.com/cwv76ke.

97

98

99

100

101

102

103

104

105

106

107

108

0 2 4 6 8 10 12

dB

Windspeed(m/s)

MeasuredbyDeltaVestasdatasheet


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17

Figure6.ContoursforoutdoorAweightedsoundpressurelevelsof39dB(orangeline),41dB(blue

line)and44dB(redline)usingthepropagationcalculationoftheDanishregulation.Windspeed8

m/s.


18/26

18

Figure7.ContoursforoutdoorAweightedsoundpressurelevelsof39dB(orangeline),41dB(blue

line)and44dB(redline),usingthepropagationcalculationoftheDanishregulations.Windspeed8

m/s.

NoisespectraatthefourpositionsselectedbyArcadis5areshowninFigure8.


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19

Figure8.ThirdoctavespectraofthecalculatedoutdoorAweightednoiseatfourselectedpositions

byArcadis1,5:7(newhomesMalberg),7B(Toustruwe,Malberg),17(Kantoorweg)and18(Europark,

Belgium).TotalAweightedsoundpressurelevelsLpAare45.1,44.1,45.2and46.2dB,respectively.

Distancestonearestturbineare467,546,381and385m.Windspeed8m/s.

Thepeaksat63and100Hzaremoreprominentthaninthesourcespectrum,sinceatthesedistancesthe

higherfrequencieshavebeenattenuatedbythesoundabsorptionoftheair.

4.2 AdditionalcommentsInadditiontotheformalquestionsraisedandgivenineachofthesubsectionsofSection3,wewereasked

toaddresscertainaspectsifpossible(seeAnnexA).Mostoftheseaspectshaveobviouslybeenmentioned

already,andafewmorewillfollowherealongwithothercomments.

Onesubjectisthestateofrepairofwindturbinesandthenoiseproduction.Wehavenospecific

knowledgeofthis,butitseemstobegenerallyagreedthatthenoisemayincreasewithimproper

maintenanceandalsonormalwearofthemechanicsandtheblades.

Anothermatteristheheightoftheturbinesanditspossibleinfluenceonthenoise.Theturbinetoweris

extraordinaryhighandtherotordiameterlargefor3.0MWturbines,whichisprobablyneededtoachieve

anadequatepowerproductionwiththelowwindconditionsoftheactualarea.

Aspecificproblemwithlargeturbinesisthatactualwindspeedprofilesvaryalotandoftendeviate

substantiallyfromthenormallyassumedlogarithmicalprofile(see,e.g.vandenBerg52,Botha

53,Palmer

54

andBowdler55). Inastableatmosphere,whichoftenexistsatnight,variationswithheightcanbemuch

largerthanassumedwithhighwindspeedattheturbineheightandlittlewindattheground.

0

5

10

15

20

25

30

35

40

45

20

25

31.

540

50

63

80

100

125

160

200

250

315

400

500

630

800

1000

1250

1600

2000

2500

3150

4000

5000

6300

8000

10000

dB

Thirdoctavefrequency(Hz)

7

7B

17

18


20/26

20

Alargevariationofwindspeedacrosstherotorareaincreasesthemodulationoftheturbinenoise,andthe

normalswishswishsoundturnsintoamoreannoying,thumping,impulsivesoundasreportedby,e.g.,

vandenBerg56,57

andPalmer58.Theeffectismoreprominentwithturbineswithlargerotors,wherethe

differenceinwindspeedbetweenrotortopandbottomcanbesubstantial.Theeffectisusuallynot

reflectedinnoisemeasurements,whicharemainlycarriedoutinthedaytime,whenthelogarithmicprofile

ismorecommon.

Anotherissueregardingatmosphericconditionsisthatitisoftenclaimedtoreflectaworstcasesituation,

whendownwindpropagationisassumedforcalculationsofneighbornoise.Thisisbarelytrue,though.Itis

correctthatnoiseisusuallymoreattenuatedinupwindconditions,andmostpeoplehaveeveryday

experiencewiththis.Theeffectisduetobendingofthesoundwavesfromrefractionintheatmosphere,

whichcausesupwindshadowzones.However,fornoisesourcesoftheheightoflargewindturbines,

shadowzonesarenormallyfurtherawaythanusualnoisecontours,includingthosegiveninthisreport.

Itisalsoourexperiencethatcomplainingneighborsdonotexplicitlymentiondownwindconditionsasthe

worstsituation.Sometimes,nuisancesarementionedasbeingmoresevereinotherwinddirections,which

maybeexplainedbyadirectionalpatternoftheturbinecombinedwithitsorientationtotheneighbor.

ItisalsorelevanttomentionthatinDenmarkthereisanabsoluteminimumdistancetodwellings

irrespectiveofthenoiseoffourtimesthetotalheightoftheturbinetopreventthattheturbinesappear

toogiganticandintrusiveattheneighborsplace.Sincethetotalheightoftheplannedturbinesis175

meter,theabsoluteminimumdistanceinDenmarkwouldbe700meter.

5Concluding

remarks

Arcadisunderstandinganduseofourdataarecorrect,exceptforafewminorissues.AlsotheirunderstandinganduseofthenewDanishregulationoflowfrequencynoisearecorrect.

However,thecalculationofthenewDanishregulationunderestimatestheindoorlowfrequencynoise.Wherethe20dBlimitisjustmet,realmeasurementswillgivevaluesthatexceedthelimitby

severaldecibelsinmanyhouses.

Acreditablecalculationoftheproposedprojectshowsthattheindoorlowfrequencynoisewillexceed20dBinmanyhousesinalargegeographicalarea.

Thisisimportant,sincetheperceivedannoyancefromlowfrequencynoiseincreasesstrongly,whenthenoiseexceeds20dB.

Prolongedexposuretoaudiblelowfrequencysoundmaycausefatigue,headache,impairedconcentration,sleepdisturbanceandphysiologicalstress.

Thecalculationsusethemostlikelyvaluesofemittednoiseanddonotrepresentworstcasescenarios.Thereisnomargintoaccountforuncertaintyand/orincreasednoiseduringageingof

theturbines.

Wedonotconsidernoiselimits(suchastheDutch)basedonyearlyaveragesassuitableforwindturbinenoise.Incommonactualsituations,DutchandDanishlimitsforthetotaloutdoornoisein

dwellingareasareexceededinmanylocations.

InDenmark,thereisaminimumsetbackdistanceirrespectiveofnoiseoffourtimestheturbineheight,i.e.700meterforturbinesproposed.


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21

References:

1A.Boukich,H.D.Koppen,AkoestischonderzoekWindparkLanakerveldteMaastricht,ArcadisNederlandBV,

reference075734629:A,30.September2011.2H.D.Koppen,AanvullendakoestischonderzoekWindparkLanakerveldtoMaastricht,ArcadisNederlandBV,

reference075723545:B,30.September2011.3H.D.Koppen,Geluids enslagschaduwonderzoekoptimalisatiealternatiefWindparkLanakerveldteMaastricht,

ArcadisNederlandBV,reference075828351:B,7.November2011.4H.D.Koppen,WindparkLanakerveld,kansoplaagfrequentgeluidvanwegeoptimalisatiealternatief,Arcadis

NederlandBV,reference075898401:0.3, 27.November2011.5H.D.Koppen,LaagfrequentgeluidvanwegehetWindparkLanakerveld(LowfrequencynoisefromWindpark

Lanakerveld),ArcadisNederlandBV,reference076249008:A,13.February2012.6H.Mller,C.S.Pedersen,Lowfrequencynoisefromlargewindturbines,JournaloftheAcousticalSocietyofAmerica,

129(6),37273744(2011).7Bekendtgrelseomstjfravindmller(Statutoryorderonnoisefromwindturbines),nr.1284,Miljministeriet

(MinistryoftheEnvironment),15.december2011.8S.Nielsen,K.D.Madsen,MeasurementofnoiseemissionfromaVestasV1123.0MWmode0windturbine,Delta

reportAV161/11,performedforVestas,revisedversion20.September2011.9Generalspecification;V1123.0MW,VestasWindSystems,Document00119181V05,18.August2011.

10Generalspecification;V802.0MW,VestasWindSystems,Document944406V19,22.July2010.

11H.Mller,C.S.Pedersen,Humanhearingatlowfrequencies,Noise&Health,6(23),3757,2004.

12B.Sndergaard,K.D.Madsen,LowfrequencynoisefromlargewindturbinesResultsfromprevioussoundpower

measurements,ReportAV137/08,Delta,30.April2008.13

B.Sndergaard,K.D.Madsen,LowfrequencynoisefromlargewindturbinesResultsfromsoundpower

measurements,ReportAV136/08,Delta,revisedversion19.December2008.14

B.Sndergaard,K.D.Madsen,LowfrequencynoisefromlargewindturbinesSummaryandconclusionson

measurementsandmethods,ReportAV140/08,Delta,revisedversion19.December2008.15D.Hoffmeyer,B.Sndergaard,LowfrequencynoisefromlargewindturbinesMeasurementsofsoundinsulationof

facades,ReportAV1097/08,Delta,30.April2008.16

K.D.MadsenandT.H.Pedersen,LowfrequencynoisefromlargewindturbinesFinalreport,ReportAV1272/10,

Delta,21.November2010.17

H.Mller,C.S.Pedersen,S.Pedersen,Lavfrekventstjfrastorevindmlleropdateret2011(Lowfrequencynoise

fromlargewindturbinesupdated2011),AalborgUniversity,ISBN9788792328632,26.May2011.18

F.vandenBerg,E.Pedersen,J.Bouma,R.Bakker,WINDFARMperceptionVisualandacousticimpactofwind

turbinefarmsonresidents,FinalReport,UniversityofGroningen,UniversityofGothenburg,June2008.19

L.D.Whittle,S.J.Collins,D.W.Robinson,Theaudibilityoflowfrequencysounds,JournalofSoundandVibration,21

(4),431448(1972).20

H.Mller,J.Andresen,Loudnessofpuretonesatlowandinfrasonicfrequencies,JournalofLowFrequencyNoise

andVibration,3(2),7887(1984).

21M.A.Bellmann,V.Mellert,C.Reckhardt,H.Remmers,Perceptionofsoundandvibrationatlowfrequencies,

collectedpapersfromtheJointMeetingBerlin99ofASA,EAAandDAGA,Berlin,Germany,1999,ISBN398045685

4.AbstractinJournaloftheAcousticalSocietyofAmerica,105,1297.22

ISO226AcousticsNormalequalloudnesslevelcontours,InternationalOrganizationforStandardization, Geneva,

2003.23

J.Andresen,H.Mller,Equalannoyancecontoursforinfrasonicfrequencies,JournalofLowFrequencyNoiseand

Vibration,3(3),19(1984).24

H.Mller,Annoyanceofaudibleinfrasound,JournalofLowFrequencyNoiseandVibration,6(1),117(1987).25

Y.Inukai,N.Nakamura,H.Taya,Unpleasantnessandacceptablelimitsoflowfrequencysound,JournalofLow

FrequencyNoise,VibrationandActiveControl,19(3),pp.135140(2000).26

J.K.Subedi,H.Yamaguchi,Y.Matsumoto,M.Ishiharatil,Annoyanceoflowfrequencytonesandobjectiveevaluation

methods,JournalofLowFrequencyNoise,VibrationandActiveControl,24(2),8196(2005).


22/26

22

27B.Berglund,P.Hassmn,S.R.FJob,Sourcesandeffectsoflowfrequencynoise,JournaloftheAcousticalSocietyof

America,99,29853002(1996).28

J.Bengtsson,K.P.Waye,A.Kjellberg,Evaluationsofeffectsduetolowfrequencynoiseinalowdemandingwork

situation,JournalofSoundandVibration,Vol.278,8399(2004).29

K.P.Waye,J.Bengtsson,A.Kjellberg,S.Benton,Lowfrequencynoisepollutioninterfereswithperformance,Noise

&Health,4(13),3349(2001).30

K.P.Waye,A.Clow,S.Edwards,F.Hucklebridge,R.Rylander,Effectsofnighttimelowfrequencynoiseonthecortisol

responsetoawakeningandsubjectivesleepquality,LifeSciences,72,863875(2003).31

B.Berglund,T.Lindvall(Editors),Communitynoise,ArchivesoftheCenterforSensoryResearch,2(1),Stockholm

UniversityandKarolinskaInstitute,1995,preparedfortheWorldHealthOrganization.32

K.Bolin,G.Bluhm,G.Eriksson,M.E.Nilsson,Infrasoundandlowfrequencynoisefromwindturbines:exposureand

healtheffects,EnvironmentalResearchLetters,6,16(2011).33

Lavfrekventstjfravindmller(Lowfrequencynoisefromwindturbines),Memorandom,DanishEnvironmental

ProtectionAgency,31.May2006.34

H.Mller,S.Pedersen,J.K.Staunstrup,Stjfratestcenterforvindmllervedsterild(Noisefromtestcentrefor

windturbinesatsterild),AalborgUniversity,ISBN9788792328380(October2011).35IEC6140011,WindturbinegeneratorsystemsPart11:Acousticnoisemeasurementtechniques,Secondedition

2002plusAmendment12006,International TechnicalCommission,Geneva.36

D.Hoffmeyer,J.Jakobsen,Soundinsulationofdwellingsatlowfrequencies,JournalofLowFrequencyNoise,

VibrationandActiveControl,29(1),1523(2010).37

H.Mller,S.Pedersen,K.P.Waye,C.S.Pedersen,CommentstothearticleSoundinsulationofdwellingsatlow

frequencies,LettertotheEditor,JournalofLowFrequencyNoise,VibrationandActiveControl,30(3), 229231

(2011).38

J.Jakobsen,ReplytoLettertotheEditorbyProfessorHenrikMlleretal.,JournalofLowFrequencyNoise,

VibrationandActiveControl,30(3),233234(2011).39

Revisionafvindmllebekendtgrelsenforfaststtelseafgrnserforlavfrekventstj(Revisionofthestatutoryorder

withtheaimofsettinglimitsforlowfrequencynoise),reference00105863JJ/ALG,23.September2011.40

IECTS6140014,WindturbinesPart14:DeclarationofApparentSoundPowerLevelandTonalityValues,

InternationalTechnicalCommission,Geneva,2005).41

S.M.Nielsen,L.S.Sndergaard,DokumentationafstjfravindmllervedBindesbl(Documentationofnoisefrom

windparkatBindesbl),Delta,ReportAV173/11,carriedoutforJKPLocalEnergy,11.oktober2011.42

Miljrapport,VindmllerBindesbl(Environmentalreport,WindturbinesBindesbl),RingkbingSkjernKommune,

revisedversionMay2010.43

H.Mller,S.Pedersen,unpublishedcalculations,March2012.44

Generalspecification:V903MW,VestasWindsystems,Document00005450V04,30.June2009.45

Inwerkinghebbenvaneenwindturbine,Clause3.2.3,Article3.14a,Besluitalgemeneregelsvoorinrichtingen

milieubeheer,BesluitvandeMinistervanVolkshuisvesting,RuimtelijkeOrdeningenMilieubeheervan19oktober

2007,houdendealgemeneregelsvoorinrichtingenasvalidon23.March2012.46

Reken enmeetvoorschriftwindturbines,Bijlage4.bijdeRegelingalgemeneregelsvoorinrichtingenmilieubeheer,

RegelingvandeMinistervanVolkshuisvesting,RuimtelijkeOrdeningenMilieubeheervan9november2007,nr.

DJZ2007104180, houdendealgemeneregelsvoorinrichtingenasvalidon23.March2012.47E.Pedersen,HumanresponsetowindturbinenoisePerception,annoyanceandmoderatingfactors,Doctoral

thesis,OccupationalandEnvironmentalMedicine,GothenburgUniversity,2007.48

E.Pedersen,K.P.Waye,Perceptionandannoyanceduetowindturbinenoiseadoseresponserelationship,Journal

oftheAcousticalSocietyofAmerica,116,34603470(2004).49

E.Pedersen,K.P.Waye,Windturbinenoise,annoyanceandselfreportedhealthandwellbeingindifferentliving

environments,OccupationalandEnvironmentalMedicine,64,480486(2007).50

E.Pedersen,F.vandenBerg,R.Bakker,J.Bouma,ResponsetonoisefrommodernwindfarmsinTheNetherlands,

JournaloftheAcousticalSocietyofAmerica,126,634643(2009).51

Riktvrdenfrljudfrnvindkraft(Guidelinevaluesfornoisefromwindturbines),Naturvrdsverket, Swedish

EnvironmentalProtectionAgency,23.June2011,http://www.naturvardsverket.se/sv/Start/Verksamheter med

miljopaverkan/Buller/Vindkraft/Riktvarden forljudfranvindkraft/


23/26

23

52G.P.vandenBerg,Windgradientstatisticsupto200maltitudeoverflatground,ProceedingsofFirstInternational

MeetingonWindTurbineNoise,Berlin,Germany(2005).53

P.Botha,Theuseof10mwindspeedmeasurementsintheassessmentofwindfarmdevelopments,inProceedings

ofFirstInternationalMeetingonWindTurbineNoise,Berlin,Germany(2005).54

W.K.G.Palmer,UncloakingthenatureofwindturbinesUsingthescienceofmeteorology,ProceedingsofSecond

InternationalMeetingonWindTurbineNoise,Lyon,France(2007).55

D.Bowdler,Windshearanditseffectonnoiseassessment,ProceedingsofThirdInternationalMeetingonWind

TurbineNoise,Aalborg,Denmark(2009).56

G.P.vandenBerg,Effectsofthewindprofileatnightonwindturbinesound,JournalofSoundandVibration,277,

955970(2004).57

G.P.vandenBerg,Thebeatisgettingstronger:Theeffectofatmosphericstabilityonlowfrequencymodulated

soundofwindturbines,JournalofLowFrequencyNoise,VibrationandActiveControl,24(1),124(2005).58

W.K.G.Palmer,Anewexplanationforwindturbinewhooshwindshear,ProceedingsofThirdInternational

MeetingonWindTurbineNoise,Aalborg,Denmark(2009).


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AnnexA.QuestionsfromtheCityofMaastricht

1.EffectsofLowFrequencyNoisehavebeenresearchedalot.Onwhichaspectsdoestheresearch

(approach)ofMllerandPedersendifferfromthatofotherresearchers?

2.WhatarethemaineffectsofLowFrequencyNoise(LFN)onhumansandwhenspecificallydothese

effectsoccur?

3.TheDanishGovernmenthaschangedtheregulationsforerectingwindturbinesasaresultofyour

research.Isthatcorrect?Andifso,whatspecificchangeshavebeenmade?

4.RegardingtheArcadisReport,havethecalculationsandassessmentofLowFrequencyNoisebeenmade

correctlywithrespecttotheDanishmethodandstandards?Ifnot,inwhatrespectdotheydiffer?Will

recalculationleadtosubstantiallydifferentresults?

5.Inyouropinion,isthenoisespectrumreferredtoasArcadisacousticstudyinTables1and2arealistic

worstcasescenarioforcalculatingLFNeffectsproducedby3MWwindturbines?Ifnot,whynotandcan

youindicatewhatthecorrectassumptionswillbe?Willthisleadtosubstantiallydifferentresults?

6.IsitpossibletoindicatetheexpectedLFNthatwillbeproducedbytheplannedfourwindturbinesof

typeVestasV1123MW,hubheight119m.

Ifpossible,pleaseaddressthefollowinginyouranswer:

a.ApplicableDutchandBelgianlawsandregulationsandrecentjurisprudence;

b.Thestandardswithrespecttonoise(LdenandLnight)inBelgiumandtheNetherlands,howthese

standardscameabout(legalhistory)andhowthedescriptionspecialcircumstancesasreferredtointhe

ActivitiesDecreeisbeingputintopractice;

c.Thelowandhighfrequencynoiseandthestandardsapplicabletoit;

d.Thenoisespectrumofthewindturbine,thetonalandpulsatingnoise;

e.TheaspectsrelatingtocumulationwiththeexistingcompaniesandwindturbinesinBelgium;

f.The(provisional)resultsofthenoisemeasurementoftheexistingsituationinLanakerveld1;

g.Reliabilityofmeasurementsasopposedtocalculationsbasedoncomputermodels;

h.Thewindspeedinrelationtothenoiseproductionofthefourturbines;

i.TheacousticstudyoflowfrequencynoiseandtheDanishstandard;

j.Thestateofrepairofthewindturbinesandthenoiseproduction;k.ThemultiyearwindstatisticsoftheKNMI,theshaftheightofthewindturbineandthenoiseproduction

(sourcelevel);

l.Thewindspeedintheevening/nightatagreatheightandthenoiseproduction(sourcelevel);

m.TheautonomousdevelopmentofAlbertknoopandLanakerveldanditseffectonthetotalnoise

production;

n.Thedeterminationofthemaximumsourcelevelbythesupplierandtheguaranteesofthemaximum

sourcelevelgivenbythesupplier;

o.Therelationshipbetweentheshaftheightofthewindturbinesandthelowfrequencynoise;

1Thesemeasurementshavenotbeenavailableduringpreparationofthepresentreport


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25

AnnexB. EstimationoftheerrorbyusingHoffmeyerandJakobsens

insulationdata

Pedersenetal.59

havefoundthata3Dcornermeasurementmethodisusefulinfindinglevelsnearthe

maximumlowfrequencylevels,peopleareexposedtoinrooms.ThisissupportedbydatafromBrunskog

andJakobsen60,whosimulatedthesoundfieldin100room/frequencycombinationsandfoundthatthe

3Dcornermethodhitsquitecentrallythemaximumlevels,whichinhabitantsareexposedtointheopen

areasoftheroom(theirTables3and4,meanerrorbelow1dB).

Inparallelmeasurementsinninerooms,meandifferencesof0.39.6dBdependingonfrequencywereseen

betweenthe3DcornermethodandtheprocedureusedbyHoffmeyerandJakobsen36(measurements

reportedbyHoffmeyerandSndergaard15andbyHoffmeyer

61,respectively).

Anestimatederrorinthemiddleofthisrange,i.e.5dB,isthusproposedforthetotalindoorlowfrequency

soundlevel.Thisisaconservativeestimate,sincethemaincontributionsareusuallyfromfrequenciesat50

Hzorabove,andatthesefrequenciesdifferencesareabout5dBorhigher.

AdifferenceofthesameorderofmagnitudeissupportedbyPedersenetal.sownmeasurementsinthree

rooms(theirFigure20).

Finally,MoorhouseandRamadorai62foundthatthepoweraverageofmeasurementsinalownumberof

arbitrarypositionsasintheISO140series63underestimatesthetrueroompoweraverageby23dBor

moreatfrequenciesbelow125160Hz.ISO140hasfivepositions,HoffmeyerandJakobsenonlythree.

Pedersenetal.foundthatthehighlevelareasare34dBabovethetrueroompoweraverage.

Consequently,

this

also

leads

to

a

conservative

estimate

of

5

dB

for

the

error

from

using

Hoffmeyer

and

Jakobsensdata.

References:

59S.Pedersen,H.Mller,K.P.Waye,Indoormeasurementsofnoiseatlowfrequencies Problemsandsolutions,

JournalofLowFrequencyNoise,VibrationandActiveControl,26(4),249270,2007.60

J.BrunskogandF.Jacobsen,Measurementsoflowfrequencynoiseinrooms,Memorandum(DanishEnvironmental

ProtectionAgency,2008).61

D.Hoffmeyer,Supplerendedatabehandlingafresultateraflydisolationsmlingergennemfrtiprojektet

Lavfrekventstjfrastorevindmller(Supplementarydataprocessingofsoundinsulationmeasurementscarriedout

intheprojectLowfrequencynoisefromlargewindturbines),ReportRL20/08,Delta,29.September2008.62

A.Moorhouse,R.Ramadorai,Measurementoftheaveragesoundpressurelevelinaroomatlowfrequencies,TheThirteenthInternationalCongressonSoundandVibration,Vienna,2006.63

ISO140,AcousticsMeasurementofsoundinsulationinbuildingsandofbuildingelements,International

OrganizationforStandardization,Geneva,1998.


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26

AnnexC. Spectraofemittedsoundusedincalculations

Frequencydistributionsofemittednoisearenotavailablefromtheproducer.Relativespectrumvalues

frommeasurementsoftheV1123.0MW8turbinehavethereforebeenappliedtothedatasheetvaluesfor

thetotalnoiseoftheV802.0MW10andV1123.0MW9turbines.Thisisthesameprocedureasusedby

Arcadis5.SeealsoSection3.5.

Table4.SourcespectrausedfortheV802.0MWandV1123.0MWturbinesandthebackground

data.AlldataaregivenasAweightedsoundpowerlevelsindecibels.

MeasuredforV112

at8m/s

Datasheet8m/s

V80 V112

TotalLWA 106.0 105.2 106.5

Frequency Relative Usedincalculations

10 45.2 60.8 44.4 45.7

12.5 49.9 56.1 49.1 50.4

16 56.3 49.7 55.5 56.8

20 65.9 40.1 65.1 66.4

25 70.4 35.6 69.6 70.9

31.5 70.3 35.7 69.5 70.8

40 74.9 31.1 74.1 75.4

50 77.9 28.1 77.1 78.4

63 87.0 19.0 86.2 87.5

80 86.2 19.8 85.4 86.7

100 92.1 13.9 91.3 92.6

125

89.3

16.7

88.5

89.8

160 90.0 16.0 89.2 90.5

200 91.4 14.6 90.6 91.9

250 90.4 15.6 89.6 90.9

315 91.9 14.1 91.1 92.4

400 92.0 14.0 91.2 92.5

500 92.6 13.4 91.8 93.1

630 95.6 10.4 94.8 96.1

800 95.5 10.5 94.7 96.0

1000 96.9 9.1 96.1 97.4

1250 96.9 9.1 96.1 97.4

1600 95.0 11.0 94.2 95.5

2000 95.2 10.8 94.4 95.7

2500 92.8 13.2 92.0 93.3

3150 91.6 14.4 90.8 92.1

4000 89.9 16.1 89.1 90.4

5000 84.1 21.9 83.3 84.6

6300 80.8 25.2 80.0 81.3

8000 78.8 27.2 78.0 79.3

10000 77.8 28.2 77.0 78.3

assessment of low‐frequency noise from wind turbines in maastricht

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