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Presentation on theme: "PRESENTATION ON WIND TURBINE AM by Geoffrey Weller BSc CEng FIET."— Presentation transcript:


2 Introduction ETSU-R-97 (ETSU) is failing to protect neighbours from Amplitude Modulation ETSU is used to assess noise in planning applications. Embedded into government policy Additional protection for AM is needed because AM may exceed maximum level quoted in ETSU I will summarise my Proof of Evidence, add recent events, amplify previous conclusions

3 What is AM? To demonstrate the character of AM, I would like to play two audio files.

4 Source: Dick Bowdler FIOA Noise Consultant

5 Source: Recordings of Nature websiteRecordings of Nature There are actually two separate recordings in this file.

6 Proof of Evidence The DTI commissioned the 2006 Hayes McKenzie Partnership report: The Measurement of Low Frequency Noise at Three UK Wind Farms

7 Recent and Forthcoming Papers From 5th International Conference on Wind Turbine Noise Denver 28-30 August 2013 Audible amplitude modulation - results of field measurements and investigations compared to psychoacoustical assessment and theoretical research Mike Stigwood, Sarah Large and Duncan Stigwood, MAS Environmental Ltd, UK

8 Wind FarmLocationMW per turbine No. of turbines Hub Height (m) Reference 1Aggregate Ind NewquayCornwall0.5MW159Audio examined 2AlltwalisCarmarthenshire2.3MW1065Statement from complainant - clear case 3AskhamCumbria660kW740Salford - clear case added 4Site BBanff and BuchanANON Confirmed AM by resident - anonymous at moment 5Bears DownCornwall600kW1630Salford - clear case added 6Bicker FenLincolnshire2MW1359Statement from complainant - clear case 7Black Law, ForthSouth Lanarkshire2.3MW4282Reported by others 8Blaen BowiCarmarthenshire1.3MW346Salford - clear case but not added 9Carland CrossCornwall400kw1530In ETSU-R-97 and Salford - now repowering 10CairnmoreAberdeenshire850kW355Information on complaints is second hand 11CauseymireHighland2.3MW2160In Salford but not added by Salford 12Coal CloughLancashire400kw2430In ETSU-R-97 missed in Salford 13Cold NorthcottCornwall300kw2225In ETSU-R-97 - in Salford but not added by them 14ColdhamCambridgeshire1.75MW860Statements from complainant matches AM 15ConisholmeEast Midlands800kW2065Evidence from others 16Cotton FarmEast Anglia2MW880MAS have measured EAM 17Cruach MhorArgyll & Bute850kw3545Salford - but not added 18Crystal RigScottish Borders2.3MW51 + 960 + 80Evidence from others 19DalswintonDumfries2MW1580Confirmed by the LA and affected resident 20DarracottDevon850kW350Complaints by residents of AM clearly ID AM 21Deeping St NicholasLincolnshire2MW859In Salford and added, MAS confirmed 22DelaboleCornwall2.3MW499 (tip)Direct complaints and advice of acoustician 23Forestmoor, BradworthyDevon1MW348Evidence of others 24Four BurrowsCornwall300kW1530In Salford - 'another' noise complained of 25FullabrookDevon3MW2265Complaints by many residents of AM, post Salford 26Gedney Marsh (Red House)Lincolnshire2MW659Indirect evidence 27Glens of FoundlandAberdeenshire1.3MW2046In Salford but not added 28GlyndebourneLewes District850kW144Independent source - see also article in Private Eye No.1334 29Hadyard HillSouth Ayrshire2.5MW5260-70In Salford, possible case, but no direct evidence 30Hafoty UchaGwynedd850kW139-44In Salford, questionable case, but no direct evidence 31Harlock HillCumbria500kW535In Salford, but no direct evidence 32HazleheadYorkshire2MW360Indirect complaints from residents - monitoring by developer being undertaken

9 Wind FarmLocationMW per turbine No. of turbines Hub Height (m)Reference 33High VoltsCounty Durham2750kW360Indirect evidence 34Hill of EastertonAberdeenshire850kW345Indirect evidence / information 35KessinglandSuffolk2.05MW280Complaints and MAS measured, post Salford 36Knabs RidgeNorth Yorkshire2MW858Complaints and MAS measured - post Salford 37LissettYorkshire2.5MW 1280 Controls introduced to reduce noise 38Llandinam P&LWales0.3MW10331In ETSU-R-97 39LlangwryfonCeredigion0.85MW1140Indirect information - complaints from residents 40Llyn AlawAnglesey600kW3431In Salford and WAS added 41Lynch KnollGloucestershire500kW142In Salford but not added 42LynemouthNorthumberland2MW1378Indirect evidence / information 43MablethorpeLincolnshire600kW265Indirect evidence 44Michelin Tyre FactoryDundee City2MW285In Salford but not added 45Moel MaelogenNorth Wales1.3MW950Indirect information, in Salford but not added 46Mynydd ClogauPowys850kW1734In Salford, possible case, but no direct evidence 47Mynydd GordduCeredigion0.5-0.6MW1934-35mIndirect information 48NewsteadCuminstown0.8MW149Multiple sources of evidence from residents 49North PickenhamNorfolk1.8MW880MAS measured - residents not complaining officially 50North RhinsDumfries2MW1160Indirect information 51Parc CynogCarmarthenshire720-850kW5+660When extended in size 52Penrhyddlan & LlidiatywaunPowys300kW10345Noise problems noted in ETSU-R-97 53Red Tile / WarboysCambridgeshire2MW1259MAS measured and complaints - missed by Salford 54Rhyd y GroesCeredigion300kW2431Noise problems noted in ETSU-R-97 55Royd MoorSouth Yorkshire500kW1335In Salford but not added, MAS heard 56Site P - single turbinePembrokeshireANON Confirmed by EHO 57SkelmonaeEllon, Aberdeenshire0.8MW464Controls in place to reduce noise 58South SharpleyEasington District1.3MW265Evidence from affected residents 59St BreockCornwall450kW1135In Salford but not added 60SwaffhamNorfolk1.8MW167Complaints and MAS measured, missed by Salford 61Taff ElySouth Wales0.45MW2035Indirect information 62Tir Mostyn & Foel GochDenbighshire850kW2549In Salford but not added 63TrysglwynGwynedd400kW1425In Salford but not added 64WadlowCambridgeshire2MW1380MAS have measured and confirmed with direct observations 65Walkway Wind FarmSedgefield District2MW769Evidence from affected resident clearly identifies AM 66Wharrels Hill, BothelCumbria1.3MW876Complaints by residents of AM, post Salford 67WhittleseyCambridgeshire1.8MW180Turned off at night

10 Renewable UK Annual Conference Birmingham 5-7 November 2013 Only 3 papers will be presented on technical issues (Session B8), all of them devoted to AM noise of Onshore Wind Turbines RenewableUK AM Research Project – Overview of Phase 1 Research Findings Affective Response to Amplitude Modulated Wind Turbine Sound Mechanisms and Causes of Amplitude Modulation (AM) and Other Amplitude Modulation (OAM) of Aeroacoustic Wind Turbine Noise

11 ETSU-R-97 ETSU explains level of AM assumed in noise limits: This modulation of blade noise may result in a variation of the overall A-weighted noise level by as much as 3dB(A) (peak to trough) when measured close to a wind turbine. As distance from the wind turbine/wind farm increases, this depth of modulation would be expected to decrease as atmospheric absorption attenuates the high frequency energy radiated by the blade. The term ‘as much as’ indicates the maximum level of AM envisaged, and cannot be interpreted as a typical or indicative value. It is clear that lower levels were expected at increased distance, such as at a neighbouring property

12 Statutory Nuisance Without any national standards for AM, it is suggested that noise problems can use the Statutory Nuisance complaint procedure via the Local Authority To this effect, a 127-page report detailing a complete Wind Farm Noise Statutory Nuisance Complaint Methodology has been produced for DEFRA

13 AECOM Wind Farm Noise Complaint Methodology NANR 277 120 Appendix B: Wind Farm Complaint Investigation Flowcharts – Flow Chart 1: Overall Investigation


15 Statutory Nuisance Difficult, lengthy, risky and expensive process Local Authority may not act, or may be delayed by appeals. ‘Best practicable means’ defence often available Difficulty in proving noise nuisance –noise may last many nights, then disappear entirely for a while

16 Controls to avoid Statutory Nuisance Claims Foreseeable harm in allowing the level of AM to be uncontrolled Precautionary approach needed AM Planning Condition would be win-win for developer and neighbours

17 Conditions Den Brook planning conditions 20 and 21 regarding AM 3 dB limit for AM, the maximum value for AM specified in ETSU. ETSU has has no dose-response studies, so neither does the condition Would not inhibit properly-designed windfarms

18 Conditions The Den Brook planning condition was reviewed by Moroney and Constable: The Den Brook condition is straightforward and that it is possible for this condition to be employed in a transparent and objective manner to demonstrate the existence of excess AM in wind turbine noise.

19 Challenge to the Den Brook Conditions RES challenged the Den Brook AM planning condition – their Dr Jeremy Bass reported background noise creates false positive indications of AM The Moroney and Constable report showed how false positives could easily be avoided by correlating data with Blade Passing Frequency MAS Environmental analysed the data used by Dr Bass, and showed false positives caused by common noise sources that would be recorded and disregarded - bird calls, aircraft and car alarms.

20 Conclusions Each of the five windfarms involved in this Conjoined Public Inquiry has more turbines than Den Brook, and these are all of similar height or taller than Den Brook. Taller and more numerous turbines leads to an increased risk of AM. AM is likely to be worse in areas of low background noise such as Mid Wales. Precautionary approach needed In the absence of nationally specified controls for AM the Den Brook AM test, or another test for AM agreed by the parties involved, should be a condition of development and operation.

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