SPECIALIST NOISE COMPONENT OF COMPLIANCE AUDIT

Transcription

1 Consultants in Acoustics, Vibration & Structural Dynamics website: SPECIALIST NOISE COMPONENT OF COMPLIANCE AUDIT CAPITAL WIND FARM TF694-01F07 (REV 10) CAPITAL WIND FARM COMPLIANCE ASSESSMENT REPORT 25 OCTOBER 2012 Prepared for: GPO Box 39 SYDNEY NSW 2001 Attention: Mr John Sparkes Sydney (Head Office) Renzo Tonin & Associates (NSW) Pty Ltd ABN /418A Elizabeth St., SURRY HILLS, NSW 2010 PO Box 877 STRAWBERRY HILLS, NSW 2012 Ph (02) Fax (02) Melbourne Brisbane Gold Coast Kuwait

2 DOCUMENT CONTROL Date Revision History Non- Issued Revision Issued Revision Prepared By (initials) Instructed By (initials) Reviewed & Authorised by (initials) 12/10/2012 In-house drafts /10/2012 Issued to client as Draft 8 RT RT 25/10/2012 Issued Final 9 RT RT RT 25/10/2012 Correction for Wroxham 10 RT RT RT The work presented in this document was carried out in accordance with the Renzo Tonin & Associates Quality Assurance System, which is based on Australian Standard / NZS ISO This document is issued subject to review and authorisation by the Team Leader noted by the initials printed in the last column above. If no initials appear, this document shall be considered as preliminary or draft only and no reliance shall be placed upon it other than for information to be verified later. This document is prepared for our Client's particular requirements which are based on a specific brief with limitations as agreed to with the Client. It is not intended for and should not be relied upon by a third party and no responsibility is undertaken to any third party without prior consent provided by Renzo Tonin & Associates. The information herein should not be reproduced, presented or reviewed except in full. Prior to passing on to a third party, the Client is to fully inform the third party of the specific brief and limitations associated with the commission. The information contained herein is for the purpose of acoustics only. No claims are made and no liability is accepted in respect of design and construction issues falling outside of the specialist field of acoustics engineering including and not limited to structural integrity, fire rating, architectural buildability and fit-for-purpose, waterproofing and the like. Supplementary professional advice should be sought in respect of these issues. TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 2

3 CONTENTS 1 INTRODUCTION Objective and Scope of Works Conflict of Interest Relevant Quality Standards 6 2 DESCRIPTION OF THE SITE AND SURROUNDING RESIDENTIAL DWELLINGS 7 3 CONDITIONS OF APPROVAL Condition Condition Condition Condition Condition Condition Condition Condition REVIEW OF EXISTING NOISE COMPLIANCE ASSESSMENT REPORTS Background NCAP Stage 1 NCA Stage 2 NCA 30 5 MEASUREMENT PROGRAM AND METHODOLOGY 33 6 COMPLIANCE ASSESSMENT RESULTS Lakoona (G4) Attended Noise Survey Unattended Noise Survey Widgemore (G6) Attended Noise Survey Unattended Noise Survey La Granja (G10) Attended Noise Survey Unattended Noise Survey The Patch (H15) Attended Noise Survey Unattended Noise Survey Wroxham (H24) Attended Noise Survey Unattended Noise Survey 62 TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 3

4 6.6 Grantham Park (E7) Attended Noise Survey Unattended Noise Survey Noise Measurements at Midpoint Location Noise Measurements at Capital Substation Applicability of Low Frequency Modifying Factor Correction 78 7 CONCLUSION 80 APPENDIX A - GLOSSARY OF ACOUSTIC TERMS 81 APPENDIX B - PROJECT APPROVAL FOR THE CAPITAL WIND FARM 83 APPENDIX C - LAKOONA (G4) ATTENDED SURVEY 84 APPENDIX D - LAKOONA (G4) UNATTENDED SURVEY 86 APPENDIX E - WIDGEMORE (G6) ATTENDED SURVEY 87 APPENDIX F - WIDGEMORE (G6) UNATTENDED SURVEY 89 APPENDIX G - LA GRANJA (G10) ATTENDED SURVEY 90 APPENDIX H - LA GRANJA (G10) UNATTENDED SURVEY 92 APPENDIX I - THE PATCH (H15) ATTENDED SURVEY 93 APPENDIX J - THE PATCH (H15) UNATTENDED SURVEY 95 APPENDIX K - WROXHAM (H24) ATTENDED SURVEY 96 APPENDIX L - WROXHAM (H24) UNATTENDED SURVEY 98 APPENDIX M - GRANTHAM PARK (E7) ATTENDED SURVEY 99 APPENDIX N - GRANTHAM PARK (E7) UNATTENDED SURVEY 101 APPENDIX O - MIDPOINT ATTENDED SURVEY 102 APPENDIX P - SUBSTATION ATTENDED SURVEY 103 List of Tables Table 1 Technical Data for Suzlon S88 Turbine 7 Table 2 Locations of Wind Turbines at 7 Table 3 Distance of Residential Dwellings to Nearest Turbine (m) 11 Table 4 Locations of Sunnybrook II Meteorological Mast and WTG13 11 Table 5 Modifying Factor Corrections (Table 4.1 NSW INP) 19 Table 6 ing Required by Conditions of Approval 22 Table 7 Representative Residential Dwellings 24 Table 8 Lakoona (G4) Modification Factor Analysis 37 TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 4

5 Table 9 Lakoona (G4) Compliance Assessment 39 Table 10 Lakoona (G4) Compliance Assessment Based on Estimated Turbine Noise Levels 42 Table 11 Widgemore (G6) Modification Factor Analysis 43 Table 12 Widgemore (G6) Compliance Assessment 45 Table 13 Widgemore (G6) Compliance Assessment Based on Estimated Turbine Noise Levels 48 Table 14 La Granja (G10) Modification Factor Analysis 49 Table 15 La Granja (G10) Compliance Assessment 51 Table 16 La Granja (G10) Compliance Assessment Based on Estimated Turbine Noise Levels 54 Table 17 The Patch (H15) Modification Factor Analysis 55 Table 18 The Patch (H15) Compliance Assessment 57 Table 19 The Patch (H15) Compliance Assessment Based on Estimated Turbine Noise Levels 60 Table 20 Wroxham (H24) Modification Factor Analysis 61 Table 21 Predicted Cumulative Noise Levels at Wroxham (H24) 63 Table 22 Wroxham (H24) Compliance Assessment 64 Table 23 Wroxham (H24) Compliance Assessment Based on Estimated Turbine Noise Levels 67 Table 24 Grantham Park (E7) Modification Factor Analysis 69 Table 25 Grantham Park (E7) Compliance Assessment 71 Table 26 Grantham Park (E7) Compliance Assessment Based on Estimated Turbine Noise Levels74 Table 27 Midpoint Location Modification Factor Analysis 75 Table 28 Summary of Low Frequency Modification Factor Assessment 78 TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 5

6 1 INTRODUCTION Renzo Tonin & Associates was engaged by the Department of Planning & Infrastructure to conduct a specialist, independent acoustic compliance audit of located on the Great Dividing Range about 12 kilometres south-west of Tarago and extending along the eastern edge of Lake George in the State of New South Wales. 1.1 Objective and Scope of Works The objective of the study is to conduct an independent compliance audit of noise from the. The audit is to be undertaken by reference to and in accordance with the noise related conditions of approval issued by the Minister for Planning. Included is a full and detailed noise measurement program and assessment at the residential dwellings specified in the conditions of approval. The scope of works includes the following: a) Review the noise compliance assessment reports provided to the Department by the proponent of the Capital Range wind farm; b) Comment on the adequacy of the information provided for making findings on compliance; c) Using the information provided, make a preliminary finding on compliance; d) Conduct a comprehensive noise monitoring program and analyse the data in accordance with the requirements stipulated in the noise-related conditions of approval; and, e) Determine compliance with the noise-related conditions of approval. 1.2 Conflict of Interest The company Renzo Tonin & Associates (NSW) Pty Ltd and the author of this report declare they have no actual, perceived, potential, pecuniary or non-pecuniary interest in the wind farm operator or any of its associated companies or employees or the Department of Planning & Infrastructure or any member of staff of the Department which give rise to, or could be seen as giving rise to, a conflict of interest in relation to performing the scope of works defined above in an impartial manner and in the public interest. A signed statement to this effect has been submitted to the Department. 1.3 Relevant Quality Standards The work documented in this report was carried out in accordance with the Renzo Tonin & Associates Quality Assurance System, which is based on Australian Standard / NZS ISO Appendix A contains a description of the some of the technical terms used in this report. TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 6

7 2 DESCRIPTION OF THE SITE AND SURROUNDING RESIDENTIAL DWELLINGS The approved development at comprises 67 wind turbines located in three groups, namely, Groses Hill Group to the north, Ellenden Group to the south-west and Hammonds Hill Group to the south-east. The turbines are located on visually prominent ridgelines or hilltops elevated above the adjacent rural lands (rising approximately m above the surrounding terrain). Bungendore Road is situated to the east of the project site and carries a relatively low volume of vehicular traffic. The total generating power of the wind farm is 140.7MW. To the north-east of the project site at a distance of approximately 5-10km is situated the Woodlawn Wind Farm development comprising 23 turbines with a generating power of 48.3MW. However, with the exception of one residential location, contributing noise from the Woodlawn development at the subject sites studied in this report is not significant. The wind turbines installed at the facility are Suzlon Model S88 with a hub height of 80m above ground level and a rotor diameter of 88m. The following table shows other relevant details (wind speeds specified at hub height). Table 1 Technical Data for Suzlon S88 Turbine Suzlon Model MW Hub Height m Rotor Dia m Cut-in Speed m/sec Rated Speed m/sec Cut-out Speed m/sec S The following table and Figure 1 show the physical location of the turbines. Table 2 Locations of Wind Turbines at Turbine Easting Northing TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 7

8 Turbine Easting Northing * 34* TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 8

9 Turbine Easting Northing * Turbines 33 and 34 were relocated to 68 and 69 TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 9

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11 The locations of the nearest potentially affected residential dwellings are shown in Figure 1 and in the following table the distance of those dwellings to the nearest turbine are shown. Table 3 Distance of Residential Dwellings to Nearest Turbine (m) Residence Involved with Wind Farm Nearest turbine Distance to nearest turbine (m) Lakoona (G4) No WTG67 2,056 Widgemore (G6) No WTG06 1,374 LaGranja (G10) No WTG15 1,597 The Patch (H15) No WTG57 2,587 Wroxham (H24) No WTG39 1,611 Grantham Park (E7) No WTG32 1,473 There are currently no meteorological masts installed at the project site. This requires some explanation. When background noise levels were measured by Vipac Engineers and Scientists Ltd ( Vipac ) from 9 th February to 25 th February, 2005 (the 2005 Background ) 1, wind data at 10m AGL was obtained from the site anemometer as required in the South Australian Environmental Protection Authority s Wind farms: Environmental Noise Guidelines (2003) (the SA Guidelines ). According to the Noise Compliance Assessment Plan prepared by Vipac pursuant to condition 57 of the Minister s Consent (the NCAP ) 2, that met mast was known as Sunnybrook located near WTG13 (see Figure 1). The Sunnybrook mast was eventually removed during the construction phase and replaced with a new met mast at the same ground surface elevation referred to as Sunnybrook II. Both Sunnybrook and Sunnybrook II had anemometers at 10m height AGL. The locations of Sunnybrook II and WTG13 are shown in the following table: Table 4 Locations of Sunnybrook II Meteorological Mast and WTG13 Met Mast Name Easting m Northing m Altitude m ASL Anemometer Height m AGL Sunnybrook II * WTG *See Section 4.3 NCAP Furthermore, according to the NCAP 3 there was an additional 80m mast installed on Hammonds Hill between Turbines 50 and 51. Whilst it was intended that a correlation would be undertaken for the two met masts, this information is not available. Whilst the Hammonds Hill 1 Page 8 Background Noise Monitoring. Document No TRP Vipac Engineers & Scientists, 27 April Section 4.3 RPV Operations Phase Noise Compliance Assessment Plan dated 14 Jan Ibid TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 11

12 met mast was situated closer to receiver locations to the south east of the development, the 2005 Background was not referenced to this mast so it was not used for the subsequent compliance assessment when the wind farm became operational. We have therefore conducted our own correlation between the calculated 10m height wind speed and hub height wind direction for WTG13 and WTG51 and the results are shown in the following figures: Figure 2 Correlation of 10m Wind Speed for WTG13 and WTG51 TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 12

13 Figure 3 Correlation of Hub Height Wind Direction for WTG13 and WTG51 TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 13

14 In these figures, the blue line represents the line of equality, the line of equal wind speed and wind direction for the two sites. The red line represents the line of linear regression for the scatter of data. Analysis conducted in accordance with the SA Guidelines is likely to be more sensitive to wind speed than wind direction because wind direction is not a factor in that analysis other than in broad terms (that is, the resolution required would not be greater than 45 degrees representing the eight points on a compass). In respect of wind speed, however, this is directly correlated to the noise level. The SA Guidelines state at Section 3.2: Therefore the wind speed measurement location at the wind farm site should not: be significantly affected by the operation of the WTGs in their final location provide lower wind speed results than other locations on the wind farm site, where those locations will house WTGs that affect the noise level at a relevant receiver. For large or topographically diverse wind farm sites, the suitability of the wind speed measurement location may need to be confirmed as part of the development assessment process. An examination of the scatter in Figure 2 shows that the wind speeds measured at the selected meteorological mast location (i.e. Sunnybrook and Sunnybrook II) may provide lower wind speed results than other locations on the wind farm site. In our opinion it would have been preferable for the noise assessment to have selected at least two wind speed measurement locations and possibly three, one for each turbine group. This would have provided wind information more relevant to each residential location. However, as this is not a consideration in any of the conditions imposed in the Minister s Consent, it cannot be a consideration of this audit. Sunnybrook II and the Hammonds Hill masts were eventually removed and, as previously stated, there are presently no met masts servicing Capital wind farm. The four permanent monitoring towers referred to in the Environmental Assessment were apparently never constructed. 4 Clearly, this is a relevant issue in terms of determining compliance with the Ministers Consent as there are no meteorological towers from which to obtain the required 10m wind speed data as required in the SA Guidelines. The only means of obtaining any wind information is from the turbines themselves which are fitted with anemometers on the nacelle. However, the flow of wind through the turbine blades and over the nacelle is likely to influence the readings of the anemometers. 4 Table 3.6 Environmental Assessment Vol 1 prepared by Connell Wagner dated Feb 2006 TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 14

15 We have requested but have not been able to obtain information about the accuracy of meteorological information gained from the nacelle anemometer. We understand that the wind speed is corrected for the influence of rotor wash and wake of the blades and there is no correction for wind direction. This adds uncertainty to the wind speed and wind direction values and the accuracy of that data is therefore unknown. Clearly, data from a meteorological mast would have been preferred. As there is no requirement in the conditions imposed in the Minister s Consent, for the proponent to maintain operational permanent monitoring towers, other than expressing an opinion about the accuracy of the data, this cannot be a consideration of this audit. TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 15

16 3 CONDITIONS OF APPROVAL The conditions of approval for the are annexed hereto in Appendix B. The specific clauses relating to operational noise are numbered 53 to Condition Noise generated from the Development must not exceed the equivalent noise level (LAeq,10) adjusted for any tonality as presented in the tables below. 10m (height) wind speed (m/s) Noise Level L Aeq 10 minute at receiver locations* Property described in the EA as Lakoona (G4) Property described in the EA as Widgemore (G6) Property described in the EA as La Granja (G10) Property described in the EA as The Patch (H15) m (height) wind speed (m/s) Noise Level L Aeq 10 minute at receiver locations* Property described Property described in the EA as in the EA as (E7) Wroxham (H24) *Receiver locations as identified in the Environmental Assessment Environmental Assessment prepared by Connell Wagner PPI dated February If compliance assessments are required at other non-associated residences as identified in the Environmental Assessment, the applicable noise limits are L Aeq 10 minute 35dB(A) where the predicted level is below L Aeq 10 minute 35dB(A), and the TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 16

17 predicted level is above L Aeq 10 minute 35dB(A). The predicted levels are identified in the aforementioned Environmental Assessment The last sentence in the note after the tables is ambiguous. Read literally, it means that at other non-associated residences, the applicable noise limit is L Aeq 10 minute 35dB(A) irrespective of the predicted level. We note that in the NCAP, at Section 3 where the tables and the note are repeated, the phrase is modified by inserting the words where it as follows the applicable noise limits are L Aeq 10 minute 35dB(A) where the predicted level is below L Aeq 10 minute 35dB(A), and the predicted level where it is above L Aeq 10 minute 35dB(A). This has an entirely different meaning. This is not an issue as far as the compliance audit is concerned because it does not deal with residences other than those listed in the tables. It is not possible to directly measure the LAeq(10min) from the development because the total noise level includes noise from other sources, particularly noise from vegetation (or wind noise as it is commonly referred to). Condition 59 requires that the noise compliance assessment must be undertaken in accordance with the procedures presented in the SA Guidelines. Those procedures do not require the level of wind farm noise to be determined as an absolute level as required in the tables above. The SA Guidelines assume that the total noise level measured comprises a contribution from wind noise and from the development and the adopted criterion there-in does not require noise from the development to be separated from the total noise level. There is, therefore, a disparity between the requirement to adopt the procedures in the SA Guidelines and the requirement to extract the noise from the development so as to compare it with the limits stipulated in the tables above. As a consequence, any methodology adopted for the purpose of noise compliance assessment in accordance with Condition 53 will have limitations. This could not be averted by turning the turbines on and off for a brief period of time because that result would only apply for the weather conditions applicable at the time. In this report, we therefore adopt a methodology in Section 4 which we believe to be reasonable in order to overcome the difficulties noted above. There may be other methodologies which may also be reasonable. We do not imply our methodology is exclusive. We note that Condition 53 references the noise limits to a 10m height integer wind speed, however, there is no requirement for the proponent to measure the wind speed at 10m height. As stated in the previous section, there are now no meteorological masts servicing Capital wind farm which prima facie presents a practical difficulty in acquiring the wind speed data. As explained in the next section, the data provided by the nacelle anemometer on WTG 13 is used in this report. The wind speed at 10m height must therefore be extrapolated and at best the result will be approximate only. TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 17

18 Unfortunately, this introduces another variable in determining compliance which, as explained above, is already made difficult by the requirement to determine the LAeq(10minute) contribution from the development on its own. 3.2 Condition The noise limits applied to the eight properties identified in Condition No. 53 must be applied to all residences that were identified as being representative as described in Table 1: Representative background sites with similar noise criteria, Appendix H1 Background Noise Monitoring found in Volume 2 Appendices to the Environmental Assessment. It is noted that this condition refers to eight properties, however, only six properties are specified in Condition 53. We presume this is a typographical error. This study is concerned with only the closest residential receivers to the project site. If noise levels comply at those residences they will also comply at other residences located further from the development. 3.3 Condition Noise from the Premises is to be measured at the most affected point within the residential boundary, or at the most affected point within 30 metres of the dwelling where the dwelling is more than 30 metres from the boundary, to determine compliance with the noise level limits set out in the tables at Condition No. 53. All of the dwellings are located further than 30 metres from the boundary of their lots and therefore the noise assessment location is at the most affected point within 30 metres of the dwelling. A distance of 30m is used in this report unless there is an impediment requiring a shorter distance to be used. 3.4 Condition The modification factors presented in Section 4 of the New South Wales Industrial Noise Policy (NSW EPA, January, 2000), must be applied to the measured noise level where applicable. This clause refers to the modifying factors defined in Section 4 of the EPA s NSW Industrial Noise Policy ( INP ). The modifying factors are penalties applied for a noise deemed to be tonal, low frequency, impulsive or intermittent in accordance with the following table: TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 18

19 Table 5 Modifying Factor Corrections (Table 4.1 NSW INP) Factor Assessment/ measurement When to apply Correction 1 Comments Tonal noise One-third octave or narrow band analysis Level of one-third octave band exceeds the level of the adjacent bands on both sides by: 5 db or more if the centre frequency of the band containing the tone is above 400 Hz 8 db or more if the centre frequency of the band containing the tone is 160 to 400 Hz inclusive 15 db or more if the centre frequency of the band containing the tone is below 160 Hz 5 db 2 Narrow-band frequency analysis may be required to precisely detect occurrence Low frequency noise Measurement of C-weighted and A-weighted level Measure/assess C- and A- weighted levels over same time period. Correction to be applied if the difference between the two levels is 15 db or more 5 db 2 C-weighting is designed to be more responsive to lowfrequency noise Impulsive noise A-weighted fast response and impulse response If difference in A-weighted maximum noise levels between fast response and impulse response is greater than 2 db Apply difference in measured levels as the correction, up to a maximum of 5 db. Characterised by a short rise time of 35 milliseconds (ms) and decay time of 1.5 s Intermittent noise Duration Subjectively assessed Single-event noise duration may range from 1.5min to 2.5hr Level varies by more than 5 db 5 db Adjustment to be applied for nighttime only. One event in any 24-hour period 0 to 20 db(a) The acceptable noise level may be increased by an adjustment depending on duration of noise. (See Table 4.2) Maximum adjustment Refer to individual modifying factors Where two or more modifying factors are indicated Maximum correction of 10 db(a) 2 (excluding duration correction) Notes: 1.Corrections to be added to the measured or predicted levels. 2.Where a source emits tonal and low-frequency noise, only one 5-dB correction should be applied if the tone is in the low-frequency range. See definitions in Section 4.2 NSW INP TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 19

20 3.5 Condition The Applicant must prepare a Noise Compliance Assessment Plan which must be submitted to the DEC prior to Commissioning of the wind turbines. The Noise Compliance Assessment Plan must outline how the Noise Compliance Assessment, as described in Conditions Nos , will be achieved. This condition was complied with by submission of the NCAP previously referred to. 3.6 Condition The Noise Compliance Assessment must include, but not be limited to: (a) an assessment of the performance of the wind farm against the noise limits contained in Condition No.53. (b) a commitment that noise compliance monitoring must be undertaken within three calendar months of the commissioning of the wind turbines at the locations identified in Condition No If prevailing meteorological conditions do not allow the required monitoring to be undertaken in this period, the DEC must be notified and an extension of time may be sought; and (c) a requirement that all noise compliance monitoring results are to be submitted to the DEC within one month of completion of the monitoring. The DEC may request that additional noise compliance monitoring be undertaken and completed within a timeframe defined by the DEC. 1 The EPA may require the Proponent to repeat the Noise Compliance Assessment procedure if the initial Noise Compliance Assessment indicates that this is necessary. The EPA may require additional compliance assessment at locations not nominated in Condition No. 53 on the basis of bona fide complaint(s). The following noise compliance assessment reports were prepared by the proponent and submitted to the Department of Planning: Noise Compliance Assessment. Stage 1 of NCAP Document No 50B TRP prepared by Vipac Engineers & Scientists Ltd dated 30 Sept 2010 (the Stage 1 NCA ) Noise Compliance Assessment. Stage 2 of NCAP Document No 50B TRP prepared by Vipac Engineers & Scientists Ltd dated 30 Sept 2010 (the Stage 2 NCA ) 3.7 Condition In the event that the Noise Compliance Assessment indicates that noise from the wind turbines exceeds the noise limits contained in Condition No. 53, the Proponent must investigate and propose the mitigation and management measures that are available to achieve TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 20

21 compliance with the noise limits. The Noise Compliance Assessment must be undertaken in accordance with the procedures presented in the SA Guidelines. Note: The data obtained using the compliance assessment procedures outlined in the SA Guidelines should be used to establish the noise levels contributed by the wind farm. Other predictive compliance assessment techniques, where these techniques can be justified, may be considered. Whilst not directly applicable to wind farms, the NSW Industrial Noise Policy (INP) may provide additional guidance on predictive compliance assessment techniques. The Stage 1 NCA and the Stage 2 NCA identify no exceedences. 3.8 Condition Reasonable and Feasible noise mitigation measures are to be provided by the Proponent for no more than one new dwelling, built on any vacant lot legally existing at the date of this Approval, upon which a residential dwelling would be permissible at the same date. Noise mitigation is to be provided if the noise levels from the Development at the approved location of the new residential dwelling would exceed the SA Guidelines. Note: The intention is that this Condition of Approval does not apply to any potential future subdivision(s) that may be approved after the date of this Approval. This condition does not relate to the scope of this study. TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 21

22 4 REVIEW OF EXISTING NOISE COMPLIANCE ASSESSMENT REPORTS The conditions of approval require the following reports to be submitted: Table 6 ing Required by Conditions of Approval Condition Submitted 57 Noise Compliance Assessment Plan NCAP 58 Noise Compliance Assessment Stage 1 NCA Stage 2 NCA In this section we will: a) comment on the adequacy of the information provided for making findings on compliance; and, b) make a preliminary finding on compliance based on the information provided Background Whilst the measurement of ambient noise levels prior to the turbines becoming operational is not a requirement of the conditions of approval, the NCAP nevertheless requires the data to be used to make a correction to the measured sound levels (as described in the next section). Therefore, discussion of the 2005 Background is of relevance to the audit. The pre-commissioning ambient noise monitoring was undertaken by Vipac at ten sites of which the following seven were subsequently listed in the NCAP for assessment when the turbines became operational: Luckdale (G2) Euroka (G7) Sunnybrook 1 (G8) Gray Lot 7 (H5) The Patch (H15) Currandooley (H2) L Orizon (E2) Of these, only The Patch is referred to in the Minister s Consent and therefore there are no preoperational ambient noise measurements taken at the other sites referred to in the consent. As previously stated, however, the measurement of pre-operational ambient noise is not a requirement of any condition in the Minister s Consent. The 2005 Background contains the results of a noise survey conducted over the period 9 th February to 25 th February 2005 prior to operation of the wind turbines. The noise data was synchronised with the 10m anemometer installed on the Sunnybrook mast previously referred TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 22

23 to. The instrumentation used included both Type 1 and Type 2 noise loggers and photographs of the instrumentation and their locations are contained in the report. There is no information provided in the report in respect of wind direction during the survey period. The SA Guidelines require as follows: Data Data not adversely affected by the effects of wind or rain should be collected for a sufficient period to cover the range of wind speeds and directions generally expected at the wind farm site. The noise floor of the loggers used varies between 23-28dB(A) which is relatively high and is likely to influence the regression line especially at the low wind speed range. Four weather stations were used spread across the study area to monitor wind speed at microphone height. As stated in the report, data was excluded during periods of rain and where the wind speed at microphone height exceeds 5m/sec. We note that from the photographs that the logging equipment utilises standard 90mm windscreens which are documented to produce a noise level of 38dB(A) for a 5m/sec wind speed. 5 However, this is for a fixed wind speed which does not realistically occur in practice. The variation in wind speed will cause the noise on the windshield to vary and therefore when measuring the LA90 for an average wind speed of 5m/sec, the windshield noise will be less than 38dB(A). There is no data that we are aware of relating to this issue. Therefore, we assume a deduction of 5dB(A) when measuring the LA90. This implies the windscreen noise affecting the LA90 is (38-5=) 33dB(A) for a 90mm windscreen at an average wind speed of 5m/sec. This is to be compared with a 175mm wind screen used in this study which produces a noise level of (29-5=) 24dB(A) at 5m/sec. 6 Therefore there is the potential for the regression curves in the 2005 Background to be at a higher level than they would otherwise be. The data regression analysis is in accordance with the SA Guidelines. The results are contained in Appendix E of the report. 4.2 NCAP A Noise Compliance Assessment Plan (NCAP) prepared in compliance with Condition 57 describes the methodology for the two subsequent noise measurement surveys conducted after the turbines became operational. 5 Experimental study to determine wind-induced noise and windscreen attenuation effects on microphone response for environmental wind turbine and other applications Noise Control Eng. J. 56 (4), July-Aug Ibid TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 23

24 On page 5 of the NCAP, there is a statement that G10 is not La Granja, rather G11 is La Granja. However, in the subsequent Stage 2 NCA, G10 is referred to as La Granja and so we must assume that the statement is incorrect. There appears to be no consequence arising from this error. As previously stated, other than The Patch, background noise measurements were not obtained at the residential receivers specified in Condition 53. Because pre-operational noise levels are an important component of the NCAP, background noise measurements at nearby locations were used instead, as described in Table 1 of the NCAP as follows: Table 7 Representative Residential Dwellings Residential Location Referred to in Condition 53 Lakoona (G4) Widgemore (G6) LaGranja (G10) The Patch (H15) Wroxham (H24) Grantham Park (E7) Representative Residential Location Luckdale (G2) Euroka (G7) Sunnybrook 1 (G8) The Patch (H15) Gray Lot 7 (H5) Currandooley (H2) Reference to Figure 1 of the NCAP shows that these appear to be reasonable representative locations. Seven sites which were the subject of the pre-commissioning background noise monitoring were proposed for an initial study when the turbines became operational: Luckdale (G2) Euroka (G7) Sunnybrook 1 (G8) Gray Lot 7 (H5) The Patch (H15) Currandooley (H2) L Orizon (E2) Therefore, as explained on Page 6 of the NCAP, if noise levels complied at those locations then they would also comply at the locations specified in Condition 53 by virtue of their equivalence as specified in Table 7 above. Only if the measured noise levels were shown to exceed the predicted noise levels would it be necessary, according to the NCAP, to measure noise levels at the locations specified in Condition 53. This may also occur if there is a significant complaint. It is not explained why a noise assessment was not proposed to be undertaken at the locations specified in Condition 53. In any event, as it transpired, a noise assessment was eventually made and documented in the Stage 2 NCA but without the benefit of pre-operational background noise levels. Given that the turbines were by then in operation, it probably would not have been feasible to stop production for the purpose of measuring background noise TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 24

25 levels. Whilst this would have an effect on the accuracy of the calculations in the Stage 2 NCA, there is no requirement in the Minister s Consent to measure background noise levels. The methodology for noise compliance assessment is described in Section 4.2 of the NCAP. This section begins as follows: Since the post construction survey will be comparing sound levels at the receptors against the sound levels measured before construction, it is important to ensure that wherever possible the measurements and analysis shall be done in exactly the same way as they were done in the preconstruction survey. The following technique is to be employed: The resultant measured noise levels contain the total combined background and wind farm noise levels. The wind farm noise levels are determined by subtracting the background noise levels from the total measured noise levels. The wind farm noise levels shall then be compared with: a) the predicted noise levels at the monitored locations to provide validation of the original noise model, b) the noise level limits in the approval conditions (see section 3 above) to assess compliance. Some measurements may need to be performed with the wind farm switched off to allow the difference between the total noise levels and current background noise levels to be determined. As there is no precise method for determining the LAeq,10min from the project, this will result in uncertainty in the conclusions. A tolerance of 2dB(A) above the noise limits is proposed. If the calculated net noise levels incoming from the wind farm are significantly above (>2dBA) the values specified in Section 3 then further testing will be undertaken to identify the reasons for any exceedance of the limits. It may also be necessary to measure at other locations depending on the extent to which actual values are above predicted values. This is consistent with EPA policy. 7 The NCAP provides for attended measurements during worst case noise propagation conditions at each receiver location including testing with selected turbines switched off as described above. As previously stated, noise levels measured at a residential location will include the combined noise contribution from the wind turbines and other ambient noise, particularly wind noise from vegetation. Therefore, whilst it is theoretically possible to subtract wind noise from the total 7 Section NSW EPA Industrial Noise Policy, Jan 2000 TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 25

26 noise in order to derive an LAeq,10min contribution from the wind turbines alone, there are practical considerations which prevent an accurate result being obtained. First and foremost, subtracting noise levels that are taken over five years apart is not appropriate in our opinion as there are many aspects of the environment that could have changed over that time. Furthermore, there is no explanation provided as to whether the meteorological conditions were the same for the two surveys. This concern is further exemplified by the significant differences apparent in the noise levels between the 2005 preoperational survey and the 2010 post-operational surveys (as demonstrated in the next section). Secondly, the technique of switching off turbines to determine the noise level contribution from turbines, does not on its own demonstrate compliance with Condition 53 which requires (in accordance with the SA Guidelines) an assessment to be made over a period of approximately two weeks. Any results would relate only to the specific conditions of the test. Whilst there is clearly an attempt to do testing in worst case conditions, this is not evident from the reports. For example, with the exception of The Patch, all the on-off measurements were done during the day when temperature inversions do not occur. There is no precise method of determining the LAeq,10min from the project in accordance with Condition 53. Any method has its short-comings and whilst we have expressed the concerns above in relation to the NCAP methodology, there is no correct or preferred approach, including the methodology which we have adopted in this report. We conclude that the NCAP provides a reasonable attempt at defining a valid protocol for noise assessment from the project despite the reservations made above. 4.3 Stage 1 NCA An unattended noise survey was conducted in the months February to April 2010 at the following properties: Luckdale (G2) Euroka (G7) Sunnybrook 1 (G8) The Patch (H15) Currandooley (H2) L Orizon (E2) Gray Lot 7 (H5) was not surveyed because the owner would not give permission. The equipment comprised Larson Davis sound level meters and two Environdata Weather Master 2000 weather stations. The sound level meters are Type 1 which are suitable for use with the reservation discussed above in respect of the microphone wind shield. TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 26

27 The Sunnybrook II meteorological mast was used to obtain the 10m AGL win data for the project. There is no information in the 2005 Background in respect of wind direction during the survey in February Similarly, there is no information provided in the 2010 Stage 1 NCA. The identical survey locations were selected for noise monitoring as in the 2005 Background. For each residential location, noise and wind speed graphs are produced in Appendix C and regression curves are provided in Appendix D of the Stage 1 NCA. In order to illustrate and to comment on the methodology, we will examine in detail the results for two of the measurement locations. The result for Currandooley is produced below: Regression Line 2010 Minus 2005 Background Turbines On Turbines Off Regression Line 2010 Predicted Pre-Construction Regression Line 2005 Background Figure 4 Regression for Currandooley (Fig D-1 Stage 1 NCA ) TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 27

28 By way of explanation, the figure above shows the following: i) the Pre-Construction Regression Line 2005 Background measured in 2005 prior to the turbines becoming operational; ii) the Regression Line 2010 with the turbines operating measured in The measured noise levels include both the contribution of turbine noise and ambient noise (including wind noise); iii) the dotted line marked Regression Line 2010 Minus 2005 Background which is the calculated contribution of turbine noise level alone determined from the logarithmic subtraction of the two lines above; and, iv) the Predicted LAeq noise level (the source of which is not referenced). We note that the graph ordinate is entitled Background LA90 Noise Level (db(a)) which does not accurately apply to the metric for the predicted noise level. A more apt title should have been chosen. Despite the reservations previously made concerning subtraction of noise levels measured over five years apart, the calculated contribution of turbine noise level in this instance is within about 1dB(A) of the predicted noise level up to 7m/sec and within about 3dB(A) above 7m/sec which is a reasonable correlation. Examination of the regressions for the other associated wind farmer sites Luckdale (G2), Euroka (G7), Sunnybrook 1 (G8) and L Orizon (E2) show similar results. Also shown in Figure 4 is the result of the turbine switch off test conducted at a wind speed of 7.1m/sec. The LA90 noise level is assumed to represent the combination of turbine noise and other ambient noise (including wind noise). The LA90 best represents the combination of the LAeq turbine noise (because that is relatively constant) and the lowest levels of other ambient noise. This is the inherent assumption adopted in the compliance section of the SA Guidelines. 8 The measurement of wind farm noise is expected to be difficult due to the masking effect of the ambient noise and its influence on the base noise level descriptor (LAeq). The background noise descriptor (LA90) is used to remove this effect. In evaluating the results of the switch off test, we prefer to use the LA90 data for the reasons expressed above. The assumption is made that in subtracting the LA90 noise level with turbines off from the LA90 noise level with turbines on, this gives a reasonable estimate of the contributing LAeq turbine noise. 8 Section 4 Compliance Checking. SA Guidelines TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 28

29 The LA90 noise level with turbines on (43.2 db(a) before the shutdown) and off (40.3 db(a)) is shown as a red and green triangle respectively. 9 The LAeq contribution of turbine noise is therefore approximately 40dB(A) which is about 3dB greater than the predicted noise level at a wind speed of 8m/sec. 10 This is a reasonable correlation. Nevertheless, what should be evident by virtue of the presence of the thousands of other measurement points in the figure is that this is just one result for a particular class of weather conditions. We now turn to the results for The Patch (H15) which are shown in the following figure. Turbines On Pre-Construction Regression Line 2005 Background Regression Line 2010 Predicted Turbines Off Regression Line 2010 Minus 2005 Background Figure 5 Regression for The Patch (Fig D-6 Stage 1 NCA ) In this case, the Pre-Construction Regression Line 2005 lies above the Regression Line 2010 (except for wind speeds between 6 and 8m/sec) which is intuitively not sensible. How can 9 Table 7-10 Stage 1 NCA 10 Predictions are only reported for 8m/sec. Table 3-1 Addendum Noise Impact Assessment. Vipac 15 October 2008 TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 29

30 adding a noise (i.e. the turbines) result in a decrease in total noise level? In those circumstances, it is not mathematically possible to subtract the 2005 background levels for those wind speeds as contemplated in the NCAP. Furthermore, where it is possible to subtract the 2005 background levels between 6 and 8m/sec as shown in Figure 5 (marked Regression Line 2010 Minus 2005 Background ), the result is significantly below the predicted noise level and is a meaningless result. We now look at the turbine shut-down test. This was conducted at a wind speed of 3.5m/sec (shown as triangles on the far left hand side of the figure) and reveals an LA90 of 30.4 db(a) before shutdown and 22.4dB(A) after shutdown. The LAeq contribution of turbine noise is therefore approximately 30dB(A) which is equal to the predicted noise level at a wind speed of 4m/sec. 11 However, as previously stated, this result is valid for the particular class of weather conditions which occurred during the test. 4.4 Stage 2 NCA A second phase of noise monitoring was undertaken between 4 th June and 4 th August 2010 at the specific residential locations referred to in Condition 53. The equipment and methodology is the same as previously described for the Stage 1 NCA. Background noise levels were not measured at the specified residential locations prior to the turbines becoming operational. Therefore, data for other locations with similar characteristics was used as described in Table 1 of the NCAP. As previously stated, these appear to be reasonable choices, however, the fact that pre-operational backgrounds were not taken at these locations is likely to affect the accuracy of the assessment. For each residential location, noise and wind speed graphs are produced in Appendix C and regression curves are provided in Appendix E of the Stage 2 NCA. We will examine in detail one of the figures in Appendix E of the Stage 2 NCA to explain the methodology and conclusions of the report. We refer to Figure E-2 which is the result for La Granja (G10) (which is labelled as Green (G10)) shown below. The result for this location is typical of others. 11 Table 3-2 Addendum Noise Impact Assessment. Vipac 15 October 2008 TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 30

31 Regression Line 2010 Turbines On Predicted Turbines Off Criterion Regression Line 2010 Minus 2005 Background Pre-Construction Regression Line 2005 Background Figure 6 Regression for La Granja (G10) (Fig E-2 Stage 2 NCA ) The terms used in this figure were explained in the previous section. The Pre-Construction Regression Line 2005 Background line is the regression for Sunnybrook 1 (G8). The Regression Line 2010 Minus 2005 Background (shown as a dotted line) is the calculated contributing turbine noise level derived by subtracting the background from the measured total level. This line is to be compared with the Predicted line and the result is that the turbine noise level is significantly over-predicted for wind speeds below about 6m/sec and significantly under-predicted for wind speeds above about 8m/sec. For the lower wind speeds, the calculated turbine noise level is much lower than predicted. A possible cause is that the wind direction during the survey was not worst case, however, as wind direction is not reported this cannot be confirmed. For the higher wind speeds, the calculated turbine noise level is much higher than predicted and in fact exceeds the criterion by a large margin. The report states that the higher wind speed noise levels are dominated by background induced noise, such as wind in nearby TF694-01F07 (rev 10) Compliance Assessment 25 October 2012 Page 31