original issue 13/06/2007 - flinders council

FLINDERS ISLAND WIND FARM NOISE IMPACT ASSESMENT

Prepared by

Hydro-Electric Corporation

ARBN: 072 377 158

ABN 48 072 377 158

4 Elizabeth Street, Hobart

Tasmania, Australia

Original Issue 13/06/2007

Annex 5 - Item A1 - Oct 2014

Flinders NIA for EIA&MP - 202132-NIA Hydro Tasmania Consulting Revision No: O

Original Issue 13/06/2007 ii

DOCUMENT INFORMATION TITLE Flinders Island Wind Farm Noise Impact Assessment

Appendix to the Environmental Impact Assessment and

Management Plan

CLIENT ORGANISATION Hydro Tasmania – Business Development

CLIENT CONTACT Robert Grant

DOCUMENT ID NUMBER 202132-NIA

PROJECT MANAGER Sue Marsh

PROJECT REFERENCE E202132

Current Document Approval

PREPARED BY James Weller Sign James Weller

SRE Date 13/06/2007

REVIEWED BY Brendon Bateman Sign Brendon Bateman

SRE Date 13/06/2007

APPROVED FOR

SUBMISSION

Sue Marsh Sign Sue Marsh

SRE Date 14/06/2007

Current Document Distribution List

Organisation Date Issued To

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Revision Prepared by Reviewed

by

Approved

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The concepts and information contained in this document are the property of Hydro Tasmania Consulting. This document

may only be used for the purposes for which, and upon the conditions, the report is supplied. Use or copying of this

document in whole or in part for any other purpose without the written permission of Hydro Tasmania Consulting

constitutes an infringement of copyright.



Original Issue 13/06/2007 iii

EXECUTIVE SUMMARY

Hydro Tasmania is proposing the development of up to four wind turbines on Hayes Hill on

Flinders Island, Tasmania. This report describes the methodology and findings of the noise

impact assessment (NIA) undertaken for the development application. The NIA is based on

predicted wind farm noise levels and background data monitored at representative locations.

The methodology and acceptability limits that have been applied in this study are based on

New Zealand Standard NZS 6808-1998 and the Tasmanian Noise Measurement Procedures

Manual that was issued in July 2004. The acceptability limit criteria are as follows:

The L90, 10min1 wind farm noise level outside a noise sensitive receptor2 should not exceed the

greater of:

an amenity or absolute limit of 40 dB(A) L90,10min , or

an intrusiveness limit being the L90,10min background noise level + 5 dB,

over the operating wind speed range of the turbines.

There are five houses in the vicinity of the wind farm site.

Background monitoring has been undertaken at two representative locations around the site.

This monitoring confirmed that the eastern side of the wind farm is slightly quieter than the

western side, and can be used for post-installation compliance monitoring.

Three makes and model of wind turbine generator (WTG) are currently being considered for

the development as follows: Enercon E33, WindFlow W500 and Vestas V52 turbines. For

the purposes of this study a wind farm layout of three Vestas V52 turbines was assumed.

This model and layout is considered to be a typical scenario for the site in terms of noise

impacts.

Assessment Conclusions

For the assumed wind farm layout it is predicted that the L90,10min noise levels will be

acceptable at all existing dwellings in the vicinity of the proposed wind farm, over its full

operating wind speed range.

1 The received wind farm sound pressure level that is exceeded for 90% of the 10 minute measurement interval.

2 Eg a dwelling, school or office.



Original Issue 13/06/2007 iv

Based on existing vegetation cover and other determinants of background noise, future

houses built on the eastern side of the hill and outside the 40 dB(A) predicted noise level

contour will not be subjected to unacceptable L90,10min wind farm noise levels over the full

operating wind speed range of the assumed wind farm layout.

Commitments & Recommendations

1. When the wind turbine make, model and layout have been finalised a revised noise

impact assessment shall be submitted to Council in order to confirm that noise emissions

from the wind farm will be acceptable at all dwellings in the vicinity.

2. A compliance survey of the operational noise levels shall be conducted post

commissioning of the wind farm.

3. It is recommended that Council ensure that future housing developments are not located

too close to the wind farm in order to ensure that residents are not exposed to

unacceptable noise emissions from the facility.



Original Issue 13/06/2007 v

CONTENTS

1. INTRODUCTION 7

2. Methodology 8

2.1 Relevant Standards & Regulatory Documents 8

2.2 Acceptability Limit Criteria 8

2.3 Character of the Wind Farm Noise 9

2.4 Assessment Procedure 9

3. General Site Description 10

3.1 Characteristics of the Site 10

3.2 Structures and Land Use at the Wind Farm Site 10

4. Wind Farm Noise Level Prediction Modelling 13

4.1 Methodology 13

4.2 WTGs 14

4.3 Wind Farm Layouts 14

4.4 Noise Modelling Results 15

5. Background Monitoring and Acceptable Limit Definition 17

5.1 Methodology 17

5.2 Identification of Affected Noise Sensitive Dwellings 17

5.3 Background Monitoring Locations 18

5.3.1 Characteristics of the Monitoring Locations 18 5.3.1.1 Location A – South West of Turbines near Lady Barron Road 18

5.3.1.2 Location B - East of Turbines on the Thule Property 22

5.4 Background Monitoring & Definition of the Acceptability Limit 24

5.4.1 Monitored Data 24 5.4.1.1 Location A 25

5.4.1.2 Location B 26

5.4.2 Data Analysis for Definition of Acceptability Limits 26

6. Transformer NOISE Levels Assessment 28

7. Assessment & Conclusions 29

7.1 Acceptability Assessment 29

7.2 Conclusions of the Noise Impact Assessment 29

8. Commitments & Recommendations 30

9. REFERENCES 31

10. APPENDIX 1 Manufacturer’s Turbine Data 32

11. APPENDIX 2 Figures and Tables 33



Original Issue 13/06/2007 vi

LIST OF FIGURES Figure 3-1 Hayes Hill 30m Tower - Long Term Average Wind Rose at 30m

Level 10

Figure 3-2 Location of Existing Houses & Background Noise Monitoring Locations around the Proposed Wind Farm Site 12

Figure 4-1 Predicted Noise Level Contours at 8m/s at 10m AGL 16

Figure 5-1 Looking north at western logging location 19

Figure 5-2 Looking east at western logging location, southern turbine on left hill 20

Figure 5-3 Looking south at western logging location 21

Figure 5-4 Looking west at western logging location 21

Figure 5-5 Looking north at eastern logging location, Thule property 22

Figure 5-6 Looking east at eastern logging location, Thule property 23

Figure 5-7 Looking south at eastern logging location, Thule property 23

Figure 5-8 Looking west at eastern logging location, Thule property, towards turbines 24

Figure 5-9 Flinders Island wind data, 30m level, noise logging period of 17 days 25

Figure 11-1 Location A Monitored Background Noise and Wind Data Plots 33

Figure 11-2 Location B Monitored Background Noise and Wind Data Plots 34

Figure 11-3 Hays Hill Background Sound Pressure Level vs. Wind Speed, Location A 35

Figure 11-4 Hays Hill Background Sound Pressure Level vs. Wind Speed, Location B 36

Figure 11-5 Plot of Predicted V52 Wind Farm Noise Levels and the Acceptability Limit at House 3 37

LIST OF TABLES Table 3-1 Houses in the Vicinity of the Wind Farm Site 11

Table 4-1 Rated Sound Output of Selected Wind Turbines 14

Table 4-2 Identified Wind Turbine Sites 14

Table 4-3 Predicted WTG Noise levels at Reference Conditions dB(A) 15

Table 5-1 Acceptable Limit Noise levels at Reference Conditions 27

Table 7-1 WTG and Acceptable Limit Noise levels at Reference Conditions dB(A) 29

Table 11-1 Monitoring Location A 38

Table 11-2 Location B: East of turbines 40



Original Issue 13/06/2007 7

1. INTRODUCTION

Hydro Tasmania is proposing the development of up to four wind turbines on Hayes Hill on

Flinders Island, Tasmania. This report describes the methodology and findings of the noise

impact assessment (NIA) undertaken for the development application (DA). The NIA is based

on predicted wind farm noise levels and background data monitored at representative

locations.

The make and model of the wind turbine generators (WTGs) is not yet finalised.

Consequently this study is based on a model and layout scenario that is typical of the options

currently under consideration.

The background noise monitoring campaign was undertaken in July 2002 when the wind

farm was initially considered. Data collected during this period is still considered to be valid

because there have been no substantial changes to the site or to the immediate area since

this time.

Transformer noise is included in this study.

Construction phase noise is not dealt with in this study.




2. METHODOLOGY

2.1 Relevant Standards & Regulatory Documents

Currently there are no Tasmanian or Australian Standards issued for the assessment of

noise related to wind farms in Tasmania.

The existing Australian Standard covering the measurement of environmental noise, AS

1055.1-1997 (Ref. 3), applies to wind-independent noise sources and stipulates that

measurements are not to be taken in wind speeds above 5m/s (at 1.2m AGL). This may not

be possible at some exposed receptor locations found near a typical wind farm site, where

the wind turbine and background noise levels are both functions of the wind speed, with

similar orders of magnitude and character.

The New Zealand Standard NZS 6808-1998 (Ref. 5) was used for Woolnorth, Musselroe,

Heemskirk and Huxley Hill (King Island) wind farms setting a precedent for the assessment

of wind farm noise in Tasmania.

Consequently, the acceptability limits and methodology upon which the development permit

conditions for Flinders Island will be based are the New Zealand Standard and the

Tasmanian Noise Measurement Procedures Manual that was issued in July 2004 (Ref. 1).

2.2 Acceptability Limit Criteria

The L90, 10min3 wind farm noise level outside a noise sensitive receptor4 should not exceed the

greater of:

an amenity or absolute limit of 40 dB(A) L90,10min , or

an intrusiveness limit being the L90,10min background noise level + 5 dB,

over the operating wind speed range of the turbines.

The L90 statistical descriptor, on which the limits are based, is that which is used when

measuring wind farm noise levels. For prediction purposes, the more conventional Leq5

descriptor is used. In general, for wind farm noise levels, the Leq, 10min value is approximately

2dB greater than the L90, 10min level (Ref. 5). No adjustment has been made in this study to the

predicted levels, thus incorporating a margin of conservatism.

3 The received wind farm sound pressure level that is exceeded for 90% of the 10 minute measurement interval.

4 Eg a dwelling, school or office.

5 A type of average noise level for the 10-minute measurement period.




Note that the A-weighting applies to all noise levels in this report. This means that noise

levels are frequency-weighted to better reflect what is heard by the human ear. Essentially,

the contribution from lower frequencies is 'filtered' out.

2.3 Character of the Wind Farm Noise

It is generally assumed that the predominant character of wind turbine noise, at typical

acceptable separation distances is steady6 with no prominent tones discernible (Ref. 5).

Manufacturers supply certified information in accordance with IEC-61400-11 (Ref. 4), or

similar, to demonstrate the tone free status of their turbines.

If the received turbine noise is found to have annoying characteristics such as a distinct tone

or modulation effect such as the ‘swishing’ sound of the turbine rotor blades, a penalty of 5dB

for each effect is arithmetically added to the predicted noise level.

2.4 Assessment Procedure

This assessment comprises the following steps:

1. Plotting of the predicted 35dB(A) Leq noise-level contour at reference conditions7. Any

locations outside this contour are considered protected from unacceptable wind farm

noise levels.

2. Prediction of the received wind farm noise level at each dwelling within this 35dBA

contour, and if necessary adjusted for tonality or modulation effects.

3. Background monitoring at locations representing each of these selected dwellings to fully

define the acceptable intrusive limit criterion.

4. Acceptability assessment at each selected dwelling by direct application of the

acceptability limits described in 2.2 above.

6 Over a given 10 minute monitoring interval.

7 10m/s at 10m above ground level (AGL).




3. GENERAL SITE DESCRIPTION

3.1 Characteristics of the Site

The proposed wind farm on Flinders Island is to be located approximately 2km east of

Whitemark.

The proposed wind farm site lies on a ridge running north-south, and is exposed to the

prevailing west/south-westerlies travelling across Bass Strait (See Figure 3-2). Ground cover

is predominantly pasture grass and some low level vegetation on the slopes of the ridge, with

some 2-3m high shrubs near Nalinga Creek to the south.

Average wind direction data collected at the site from the Hayes Hill anemometer station

between 1991 and 2002 is summarised in the frequency-distribution wind roses in Figure

3-1. Hayes Hill is approximately 2 km north of the proposed wind farm.

Figure 3-1 Hayes Hill 30m Tower - Long Term Average Wind Rose at 30m Level

Clearly the prevailing winds are from the west and west-southwest.

3.2 Structures and Land Use at the Wind Farm Site

There are five houses in the vicinity of the wind farm site, the closest being to the west and

southwest of the wind farm putting them generally upwind of it in prevailing conditions (See

Figure 3-2 and Table 3-1). No other structures exist near or on the proposed wind farm site.

The land in and around the site is used mostly for grazing livestock.




Table 3-1 Houses in the Vicinity of the Wind Farm Site

House Coordinates (AGD 66)

Easting (m) Northing (m)

1 589,166 5,555,811

2 589,134 5,555,925

3 589,107 5,556,111

4 588,962 5,557,216

5 590,116 5,557,925




Figure 3-2 Location of Existing Houses & Background Noise Monitoring Locations around the Proposed Wind Farm Site




4. WIND FARM NOISE LEVEL PREDICTION MODELLING

4.1 Methodology

The noise propagation model used in this study is based on hemispherical spreading from a

point source, assumed to be the hub of the turbine rotor, with attenuation through air calculated

for each octave band.

The apparent point source sound power level at the hub of the turbine rotor (LWA) is

determined using a certified procedure in accordance with recognised standards such as

IEC-61400-11 (Ref. 4). The procedure is based on near-field measurements, which are

based on the Leq descriptor.

The sensitivity of the sound power output to wind speed (i.e. the slope of the linear response

in dBA/m/s) is also given so that the sound pressure level can be determined for a given

wind speed. For variable speed machines the response may not be linear. In this case a plot

or function may be given.

Propagation modelling is used to determine the predicted turbine sound pressure level at a

receptor location from each WTG. The model calculates attenuation due to absorption of

noise in air for each octave band, as per ISO9613-1 (Ref. 6) and then logarithmically adds

them to get the received broadband Leq sound pressure level from the WTG. An air

temperature of 15° and a humidity of 70% were assumed for this study.

For multiple WTG's the individual predicted Leq sound pressure levels are combined using

logarithmic addition.

This basic model does not take into account the shielding effects of topography and

obstacles, or the absorption effects of ground cover. The consequent degree of conservatism

(i.e. over-prediction of the noise levels) is likely to be around 1dB to 2dB when there is a line

of sight to the turbines and as much as 10dB to 12dB when there is not (Ref. 5).

The model also assumes the purely theoretical situation that all radial directions are down wind

of each turbine. Therefore the propagation field gives the worst-case noise level in any

direction. In practice there will be a few dB attenuation in the cross-wind direction and as much

as 10dB if there is any upwind component, although this will be reduced if there is no ground

between the turbines and the receiver, eg across a gully.

An independent comparison check using the CONCAWE noise model was performed (by

Vipac acoustic consultants in Adelaide) on a Roaring Forties8 wind farm layout in South

8 A joint venture subsidiary company of Hydro Tasmania and China Light & Power




Australia. This sophisticated model includes such effects as ground absorption, topography

and wind propagation. The basic model gave results within 1 dB of the more complex model,

and is therefore a good approximation of the worst-case wind propagation effect for a typical

wind farm located along a ridgeline such as Flinders Island.

4.2 WTGs

Three makes and model of WTG are currently being considered as follows: Enercon E33,

WindFlow W500 and Vestas V52.

Their respective sound power levels at reference conditions, which are similar to the rated

power output of the turbine, are given in Table 4-1.

Table 4-1 Rated Sound Output of Selected Wind Turbines

Turbine Hub Height* (m) SPWref# (dB(A)) S## (dB(A)/m/s)

Enercon E30** 50 99.0 NA

WindFlow W500 55 101.0 NA

Vestas V52 44 104.1 1.1 # Sound power level at reference conditions ie 8m/s at 10m AGL ## Response of sound power level to wind speed. *The hub heights shown are those of the subject turbine for the independent certification tests. **The sound power level information for the E33 was not sourced. The level given is for the Enercon E33’s predecessor the E30. Documentation from Enercon indicates that the E33’s sound power level is less than that of the E30 due to design improvements. The V52 hub height of 44m given in Table 4-1 is that of the subject turbine of the

independent noise level certification test. The proposed V52 hub height for Hayes Hill is 49m.

This additional 5m hub height will have a negligible effect on the noise impact.

Note that the Enercon E33 and the WindFlow W500 are significantly quieter than the Vestas

V52 turbine. This study is based on the Vestas V52 turbines.

The independent certification test report for the Vestas V52 WTG is provided as an appendix

to this report. The report indicates that no audible tones are present.

4.3 Wind Farm Layouts

Four turbine sites have been selected whose coordinates are shown in Table 4-2. The wind

farm will have a maximum of four turbines, depending on the rotor diameter of the selected

make and model.

Table 4-2 Identified Wind Turbine Sites

Location E N Land Owner




1 589,740 5,556,860 T Rowe

2 589,845 5,556,540 Thule

3 589,900 5,556,440 Thule

4 589,930 5,556,345 Thule

Figure 4-1 shows the three-turbine V52 layout for which Location 3 was not used as there

is not sufficient distance between the wind turbines. The expected received noise levels

from this scenario are similar to a four-turbine E33 or W500 wind farm.

4.4 Noise Modelling Results

The wind farm layout has been modelled using the noise model described above in Section

4.1.

The predicted Leq noise level contours are given in Figure 4-1.

Table 7-1 gives the predicted levels at each house.

Table 4-3 Predicted WTG Noise levels at Reference Conditions dB(A)

House V52 SPL*ref (Leq)

1 37

2 38

3 39

4 37

5 34

*3 x Vestas V52 wind farm sound pressure level at reference conditions ie 8m/s at 10m AGL




Figure 4-1 Predicted Noise Level Contours at 8m/s at 10m AGL

for 3 x Vestas V52 Wind Farm




5. BACKGROUND MONITORING AND ACCEPTABLE LIMIT DEFINITION

5.1 Methodology

Background monitoring is necessary to define the intrusiveness acceptability limit. At

significant wind speeds (>8m/s at 10m above the ground) background noise is predominantly

caused by the wind. Since exposure is dependent on local topographic shielding effects,

monitoring is necessary at each receptor where a potentially unacceptable wind farm noise

level is predicted.

Background monitoring is undertaken in accordance with NZS 6808. Unattended L90, 10min

measurements are taken continuously for a period of around 14 days. The noise data is

correlated with the synchronised wind speed and direction data gathered at the wind farm

site monitoring mast, using a 3rd order polynomial. The intrusiveness acceptability limit is

determined by arithmetically adding 5dBA to the correlation curve.

The large data set provides confidence in the unattended measurements by reducing the

significance of any louder-than-usual short-term background noises such as those due to

rain, running-water-following-rain, agricultural machinery, stock, intermittent road traffic and

the like. Filtering the data by time of day can actually remove similar source noises such as

those made by insects in the afternoon or birds in the morning. However, care must be

taken when using this method since confidence in the correlation may be reduced because

fewer data points are being used.

‘Binning’ a data set with a wide range of wind directions into 30o direction subsets allows an

assessment to be made of the sensitivity of the shielding characteristics of the site with

regard to wind direction. A low variation provides justification to use the whole data set, when

determining the intrusiveness acceptability limit, in order to take advantage of the greater

number of data points for the correlation.

5.2 Identification of Affected Noise Sensitive Dwellings

Figure 3-2 shows that dwellings 1, 2, 3 and 4 lie within the 35dB(A) Leq predicted noise-level

contour at 8m/s at 10m AGL. Consequently representative background data is required for

these dwellings in order to undertake an acceptability assessment of the wind farm noise

levels they are likely to experience.

Since the predicted wind farm noise level at House 5 is below 35 dB(A) it is considered

comfortably protected from unacceptable wind farm noise levels without the need for further

assessment.




5.3 Background Monitoring Locations

Only two noise loggers were available for this noise monitoring campaign. Sites were chosen

to meet the following criteria:

1) The location should be representative of nearby dwellings with relation to surrounding

vegetation, topography and line of site to the wind farm.

2) A location to both the east and west of the hill upon which the wind farm is to be sited

was necessary to capture directional shielding effects of the topography.

3) The microphone shields were not rated for wind speeds above 5m/s. Therefore, it

was necessary to obtain relatively sheltered locations.

4) The suitability of the location for post-commissioning compliance-monitoring, ie the

location should have a clear line of sight to the nearest wind turbines.

On this basis the following monitoring sites were chosen and are described in detail below.

Monitoring Location A is regarded as being representative of the existing assessable nearby

Houses 1 to 4, which are to the west and northwest of the wind farm site.

Monitoring Location B is a typical representation of the eastern side of the hill and could be

used for any future houses in the area. Currently there are no houses on the eastern side of

the hill.

5.3.1 Characteristics of the Monitoring Locations

5.3.1.1 Location A – South West of Turbines near Lady Barron Road

The monitoring location near Lady Barron Road is approximately 515m 500 from the closest

wind turbine with coordinates of E589515 and N5556040. See Table 11-1 for further

information.

The landscape around Location A consists of undulating, marshy and grassy ground. There

is a clear line of sight to all turbines from this position. A thick set of bushes lies to the west,

protecting the logger from wind noise in the prevailing wind direction. A small dam nearby

had water running through it, giving a constant trickling noise. Land past the bushes to the

coast is clear grazing land. A shed with a pump inside is located approximately 50m north.

Lady Barron Road is located 50m to the west.

The nearest dwelling – House 2 - is located approximately 380m to the west of monitoring

Location A. This dwelling has some tall vegetation surrounding it that will otherwise reduce




the background noise at the dwelling but will not shield the dwelling from the noise levels

being emitted by the wind farm.

The types of sources contributing to the background noise at Location A are:

Wind

Trickling water at the dam

Intermittent car noise from Lady Barron Road

Intermittent water pump

Figure 5-1 Looking north at western logging location




Figure 5-2 Looking east at western logging location, southern turbine on left hill




Figure 5-3 Looking south at western logging location

Figure 5-4 Looking west at western logging location




5.3.1.2 Location B - East of Turbines on the Thule Property

The monitoring site in Thules’ property is approximately 460m 2680 from the closest wind

turbine with coordinates of E590210 and N5556840. See Table 11-2 for further information.

The landscape at Location B consists of rural grazing land, on a slope down from Hayes Hill

ridge, with hills in the distance to the east and south. The location was chosen due to the

presence of bushes which would shield the logger from excessive background noise from the

wind. There is a direct line of sight to all turbines from this location. Location B is exposed to

the noise from the sea and wind has a direct line of site with the wind turbines. Location B is

on the lee side of the ridge when the prevailing wind comes from the west, which will reduce

the noise from the wind in this direction.

The sources contributing to background noise at Location B are:

Wind

Intermittent farm vehicles passing

Intermittent animal noises (bleating)

Figure 5-5 Looking north at eastern logging location, Thule property




Figure 5-6 Looking east at eastern logging location, Thule property

Figure 5-7 Looking south at eastern logging location, Thule property




Figure 5-8 Looking west at eastern logging location, Thule property, towards turbines

5.4 Background Monitoring & Definition of the Acceptability Limit

5.4.1 Monitored Data

Background noise monitoring was carried out at both monitoring locations continuously over

a three-week period form 16th July to the 2nd August 2002. The equivalent of 17 days of

continuous L90, 10min background data was collected at each location (See Figure 11-1 and

Figure 11-2).

The wind rose for the background-logging period at Flinders Island Location A is shown in

Figure 5-9.




Figure 5-9 Flinders Island wind data, 30m level, noise logging period of 17 days

A comparison of Figure 5-9 and the long term average wind data of Figure 3-1 demonstrates

that the wind distribution during the short period of noise measurement is not representative

of the long-term average distribution. The average wind speed was lower, and the wind was

predominantly from the north-west and north-east rather than from the west southwest.

Since the background monitoring session was unattended, no attempt has been made to

identify and delete any extraneous data points (eg noises from rain, insects, birds, etc). The

justification is that these relatively infrequent occurrences will have little or no effect on the

correlation, due to the relatively large data set.

Variations in the background noise levels due to time of day or wind direction have not been

investigated in detail. The spread of directions does not allow a definitive assessment of the

shielding-sensitivity to change in wind direction as several wind directions had insufficient

data points.

5.4.1.1 Location A

Wind and trickling water noises are the main contributors to background noise at this site.

At location A, the wind speed vs noise level plot exhibited a constant minimum noise level of

approximately 32 dB(A). This is assumed to be the trickling water which was about 20m

north of the noise logger.

The scatter in the data at higher wind speeds indicates that there is no obvious relationship

between shielding effects and wind direction, for the limited direction range experienced

during the monitoring period.




A shed exists on site in which there is a pump. It is unknown if this pump was used during

the logging period. Noises due to intermittent cars passing are not expected to affect 10

minute averages of background noise.

Taking into account all of the above mentioned features, all of the background data set for

site A should be used to determine the intrusive limit criterion at this particular site.

5.4.1.2 Location B

Wind was the main contributor to the background noise at this site.

Location B is generally slightly quieter than Location A. Considering the site was on the lee

side of the ridge for most of the monitoring period this is to be expected.

The clear separation of the data at higher wind speeds indicates that Location B is direction

sensitive, ie there appears to be a relationship between shielding effects and wind direction

for the limited direction range experienced during the monitoring period. But as explained

above a definitive directional-analysis is not possible.

All data from Location B will be used as the basis for the background noise levels for

assessing the intrusive limit criterion at this site.

5.4.2 Data Analysis for Definition of Acceptability Limits

Wind speeds were generally below 10m/s at 30m AGL, with the maximum 10-minute

average being just above 22m/s (Refer Figure 11-1). This range however, is more than

adequate for clearly defining the critical changeover-point (from absolute to intrusiveness) or

‘knee’ of the limit-of-acceptability curve, which approximately coincides with the typical rated

wind speed of the turbines.

Plots of background noise versus wind speed at 10m above ground level have been

produced for the full wind-direction set (See Figure 11-3 and Figure 11-4). The wind speed

and direction measurements at the anemometer were taken at a height of 30m to coincide

with the noise measurements. A wind shear coefficient was calculated using the long-term

data from the 16.5m and 30m height levels so that the wind speed for a height level of 10m

could be generated. A 3rd order polynomial correlation curve of-best-fit was defined for the

wind data. This is the equation that defines the L90, 10min background noise level.

The acceptability limit is determined by calculating the absolute and intrusive limit curve for

each site using background noise level data and applying the rules defined in Section 2.2.

See Figure 11-3 and Figure 11-4.




The derived acceptability limit at reference conditions for each monitoring location is given in

Table 7-1.

Table 5-1 Acceptable Limit Noise levels at Reference Conditions

Monitoring Site Acceptable Limit ref L90 (dB(A))

A 41

B 40




6. TRANSFORMER NOISE LEVELS ASSESSMENT

The turbines are expected to have a pad mounted transformer outside each tower. The

transformer rating is likely to be less than 1000 kVA. The maximum sound power level, from

AS 2374.6-1994 (Ref. 2), is 74 dBA for this size of transformer. This will attenuate to 20 dBA,

giving a penalised value of 25 dBA, at a distance of 200 m. Therefore the sound contribution

of the transformers can be ignored.

A smaller pole-top mounted transformer is expected to be installed to the south west of the

site, in the vicinity of background noise monitoring location A. The noise levels from this

transformer are expected to be negligible at nearby Houses 1 to 3.




7. ASSESSMENT & CONCLUSIONS

7.1 Acceptability Assessment

For each nearby house the predicted WTG noise level was compared to its representative

limit to assess acceptability of the predicted noise levels at reference conditions. See Table

7-1.

Table 7-1 WTG and Acceptable Limit Noise levels at Reference Conditions dB(A)

House Acceptable Limit * ref (L90) V52 SPL**ref (Leq) Acceptable?

1 41 37 Yes

2 41 38 Yes

3 41 39 Yes

4 41 37 Yes *Based on monitoring location A

** 3 x Vestas V52 wind farm sound pressure level at reference conditions ie 8m/s at 10m AGL

For the worst case – House 3 - the predicted WTG Leq noise level regression-curve was

compared to its representative L90 noise level limit curve (from Monitoring Location A) to

assess acceptability of the predicted Leq noise levels over the wind speed range of the

monitoring period as shown in the plot of Figure 11-5. As can be seen acceptability was

achieved.

7.2 Conclusions of the Noise Impact Assessment

For the assumed typical likely wind farm layout comprising three Vestas V52 WTGs, the

predicted Leq, noise levels are acceptable at all existing dwellings in the vicinity of the

proposed wind farm, over the wind speed range of the background monitoring period

undertaken for this study.

From the information provided in Section 2.2 and observing that the plots in Figure 11-5

diverge it can be concluded that the statement above comfortably extends to expected

L90,10min wind farm noise levels over the full operating wind speed range of the V52 WTGs.

Based on existing vegetation cover and other determinants of background noise, future

houses built on the eastern side of the hill and outside the 40 dB(A) predicted noise level

contour shown in Figure 4-1 will not be subjected to unacceptable L90,10min wind farm noise

levels over the full operating wind speed range of a three-turbine Vestas V52 wind farm.




8. COMMITMENTS & RECOMMENDATIONS

1. When the wind turbine make, model and layout have been finalised a revised noise

impact assessment shall be submitted to Council in order to confirm that noise

emissions from the wind farm will be acceptable at all dwellings in the vicinity.

2. A compliance survey of the operational noise levels shall be conducted post

commissioning of the wind farm.

3. It is recommended that Council ensure that future housing developments are not

located too close to the wind farm in order to ensure that residents are not exposed to

unacceptable noise emissions from the facility.




9. REFERENCES

Ref. 1 “Noise Measurement Procedures Manual”, July 2004, Tasmanian Department of Primary Industries, Water & Environment.

Ref. 2 AS 2374.6-1994 "Power Transformers- Determination of transformer and reactor sound levels", Standards Australia.

Ref. 3 AS 1055.1-1997 "Acoustics- the Assessment and Measurement of Environmental Noise", Standards Australia.

Ref. 4 IEC-61400-11, 1998 "Wind Turbine Generator Systems- Part 11: Acoustic Noise Measurement Techniques", International Energy Committee.

Ref. 5 NZS 6808:1998 "Acoustics- The Assessment and Measurement of Sound from Wind Turbine Generators", Standards New Zealand.

Ref. 6 ISO 9613.1, June 1993 “Acoustics – Attenuation of Sound During Propagation Outdoors – Part 1: Calculation of the Absorption of Sound by the Atmosphere”, International Energy Committee.

While all care has been undertaken to ensure that the information provided in this document

is accurate at the time of preparation, to the extent permissible by the Trade Practices Act

1974 (Cth), Hydro Tasmania Consulting takes no responsibility for any loss or liability of any

kind suffered by the recipient in reliance of its contents arising from any error, inaccuracy,

incompleteness or similar defect in the information or any default, negligence or lack of care

in relation to the preparation or provision of the information.




10. APPENDIX 1 MANUFACTURER’S TURBINE DATA




11. APPENDIX 2 FIGURES AND TABLES

Monitored Sound Data At: Location A: East of turbinesStart of Monitoring Period: 17/07/2002 13:40

End of Monitoring Period: 04/08/2002 23:50

Monitored Wind Data At: Hayes Hill @ 30m

Distance to Anemometer = 2739 m Distance to nearest turbine = 513 m

Bearing to Anemometer = 347 Degrees Bearing to nearest turbine = 54 Degrees

MONITORED BACKGROUND SOUND & WIND DATA PLOTS

Eastern Standard

Time

Monitored 10 Minute Mean Wind Speed (m/s)

0

5

10

15

20

25

15/07/02 17/07/02 19/07/02 21/07/02 23/07/02 25/07/02 27/07/02 29/07/02 31/07/02 02/08/02 04/08/02

Date

Monitored 10 Minute Mean Wind Direction (Degrees)

0

30

60

90

120

150

180

210

240

270

300

330

360

15/07/02 17/07/02 19/07/02 21/07/02 23/07/02 25/07/02 27/07/02 29/07/02 31/07/02 02/08/02 04/08/02Date

Monitored BACKGROUND L90,10min Sound Pressure Level (dBA)

0

10

20

30

40

50

60

15/07/02 17/07/02 19/07/02 21/07/02 23/07/02 25/07/02 27/07/02 29/07/02 31/07/02 02/08/02 04/08/02

Date

Figure 11-1 Location A Monitored Background Noise and Wind Data Plots




Monitored Sound Data At: Location B: east of turbinesStart of Monitoring Period: 17/07/2002 14:40

End of Monitoring Period: 02/08/2002 8:30

Monitored Wind Data At: Hayes Hill @ 30m

Distance to Anemometer = 2281 m Distance to nearest turbine = 470 m

Bearing to Anemometer = 325 Degrees Bearing to nearest turbine = 273 Degrees

MONITORED BACKGROUND SOUND & WIND DATA PLOTS

Eastern Standard

Time


0

5

10

15

20

25

15/07/02 17/07/02 19/07/02 21/07/02 23/07/02 25/07/02 27/07/02 29/07/02 31/07/02 02/08/02 04/08/02

Date

Monitored 10 Minute Mean Wind Direction (Degrees)

0

30

60

90

120

150

180

210

240

270

300

330

360

15/07/02 17/07/02 19/07/02 21/07/02 23/07/02 25/07/02 27/07/02 29/07/02 31/07/02 02/08/02 04/08/02Date

Monitored BACKGROUND L90,10min Sound Pressure Level (dBA)

0

10

20

30

40

50

60

15/07/02 17/07/02 19/07/02 21/07/02 23/07/02 25/07/02 27/07/02 29/07/02 31/07/02 02/08/02 04/08/02

Date

Figure 11-2 Location B Monitored Background Noise and Wind Data Plots




MONITORED BACKGROUND SOUND DATA AT:

y = -0.0029x3 + 0.1375x

2 - 0.6619x + 34.245

R2 = 0.4766

0

10

20

30

40

50

60

0 5 10 15 20 25


So

un

d P

res

su

re L

ev

el

(dB

A)

Monitored L90,10min Data

Acceptability limit

Poly. (Monitored L90,10minData)

ANEMOMETER DATA FROM :

Location A: South-west of turbines

Hayes Hill @ 30m

PLOT OF BACKGROUND SOUND PRESSURE LEVEL v WIND SPEED

347 0Bearing to Anemometer =

START:

END:17/07/2002 13:40

04/08/2002 23:50

Eastern

Standard Time

m2739Distance Between Instruments =

Number of Data Points

= 2202

Full Background Data Set

54 0Bearing to nearest WTG =

m513Distance to nearest WTG =

Figure 11-3 Hays Hill Background Sound Pressure Level vs. Wind Speed, Location A




Figure 11-4 Hays Hill Background Sound Pressure Level vs. Wind Speed, Location B


y = -0.0122x3 + 0.4132x

2 - 2.2102x + 30.254

R2 = 0.606

0

10

20

30

40

50

60

0 5 10 15 20 25


So

un

d P

res

su

re L

ev

el

(dB

A)

Monitored L90,10min Data

Acceptability limit

Poly. (Monitored L90,10min

Data)

ANEMOMETER DATA FROM :Location B: East of turbines

Hayes Hill @ 30m



START:

END:17/07/2002 14:4002/08/2002 08:30

Eastern

Standard Time

m2281Distance Between Instruments =

Number of Data Points = 2195

Full Background Data Set





0

10

20

30

40

50

60

0 5 10 15 20 25


So

un

d P

ressu

re L

evel

(dB

A)

Acceptability Limit Based onBackground Data atLocation A

V52 104 dBA WTG

ANEMOMETER DATA FROM :

House 3Hayes Hill @ 30m



START:

END:17/07/2002 13:4004/08/2002 23:50

Eastern

Standard Timem2739Distance Between Instruments =

54 0Bearing to nearest WTG =m513Distance to nearest WTG =

Figure 11-5 Plot of Predicted V52 Wind Farm Noise Levels and the Acceptability Limit at House 3




Table 11-1 Monitoring Location A

PARAMETER DESCRIPTION / VALUE COMMENTS

Logging Start Date & Time 16/07/2002 17:35 Eastern Standard Time

Installation Date & Time 17/07/2002 13:10 Eastern Standard Time

End Date & Time 04/08/2002 23:50 Eastern Standard Time

Monitoring Period 17 Days

Number of 10min Data Sets. 2202 Synchronised background noise, wind speed and wind direction, 10 min data triples,

starting on the hour.

Noise Measurement Position

E0589515m N5556040m

1.2m AGL, 20m S of dam,

5m E bushes

This position is in direct line of sight of the turbines, and directly between the

turbines and the nearest house, which lies to the south-west of the proposed wind

farm.

Noise Measurement

Equipment, Make & Model.

Acoustic Research Laboratories

(ARL) EL-215 Environmental

Noise Logger. Serial Number

194607

Type II (IEC-651, AS-1259). Noise Floor = 26dBA. Sampling Rate = 16 samples per

second.




Microphone Windscreen Make

& Model

Pulsar WS 90- 90mm standard

wind screen.

Anemometer Position

E0588904m N5558710m

10m AGL

Hayes Hill 30m Tower. Distance from Noise Monitoring Location = 2739m. Bearing

from Noise Monitoring Location = 347. Sampling frequency = every 2 seconds.

Closest WTG Location E0589928m N5556344m Southern turbine in Figure 4-1. Distance from Noise Monitoring Location = 513m.

Bearing from Noise Monitoring Location = 54.




Table 11-2 Location B: East of turbines

PARAMETER DESCRIPTION / VALUE COMMENTS

Logging Start Date & Time 16/07/2002 17:33 Eastern Standard Time

Installation Date & Time 17/07/2002 14:30 Eastern Standard Time

End Date & Time 02/08/2002 08:40 Eastern Standard Time

Monitoring Period 17 Days

Number of 10min Data Sets. 2195 Synchronised background noise, wind speed and wind direction, 10 min data triples,

starting on the hour.

Noise Measurement Position E0590210m N5556840m, 1.2m

AGL Near bushes and fence in gate. No houses nearby.

Noise Measurement

Equipment, Make & Model.

Acoustic Research Laboratories

(ARL) EL-215 Environmental

Noise Logger. Serial Number

194652

Type II (IEC-651, AS-1259). Noise Floor = 26dBA. Sampling Rate = 16 samples per

second.

Microphone Windscreen Make

& Model

Pulsar WS 90- 90mm standard

wind screen.




Anemometer Position

E0588904m N5558710m

10m AGL

Hayes Hill 30m Tower. Distance from Noise Monitoring Location = 2281m. Bearing

from Noise Monitoring Location = 325. Sampling frequency = every 2 seconds.

Closest WTG Location E581507m N5488601m Northern turbine in Figure 4-1. Distance from Noise Monitoring Location = 470m.

Bearing from Noise Monitoring Location = 273.
