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Table of contents

9 NOISE AND VIBRATION ........................................................................................... 9-1

9.1 Introduction .................................................................................................................. 9-1

9.1.1 Methodology ...................................................................................................................................... 9-1

9.1.2 Wind Farm Noise, Policy and Guidance ............................................................................................. 9-2

9.1.3 Construction Noise – Policy and Guidance ........................................................................................ 9-3

9.1.4 Survey Methodology .......................................................................................................................... 9-3

9.2 Existing Environment ..................................................................................................... 9-8

9.2.1 Noise Monitoring Locations ............................................................................................................... 9-8

9.2.2 Derivation of Prevailing Background Noise ...................................................................................... 9-10

9.3 Likely Significant Impacts ............................................................................................. 9-15

9.3.1 Operational Phase of Predicted Results ........................................................................................... 9-15

9.3.2 Substation ........................................................................................................................................ 9-16

9.3.3 Cumulative Impact ........................................................................................................................... 9-17

9.3.4 Potential for Tonal Content .............................................................................................................. 9-21

9.3.5 Vibration and Low Frequency Noise ................................................................................................ 9-21

9.3.6 Amplitude Modulation ..................................................................................................................... 9-23

9.3.7 Construction Phase .......................................................................................................................... 9-23

9.3.8 General Construction Activities........................................................................................................ 9-23

9.3.9 Construction Traffic .......................................................................................................................... 9-27

9.4 Mitigation .................................................................................................................... 9-28

9.4.1 Mitigation for Amplitude Modulation .............................................................................................. 9-28

9.5 Residual Impacts .......................................................................................................... 9-28

9.6 Conclusion ................................................................................................................... 9-28

17924-6001-A Noise and Vibration March 2017

9-1

9 NOISE AND VIBRATION

9.1 INTRODUCTION

This report describes the potential noise and vibration associated with the construction and

operation of the proposed Silverbirch wind farm.

The main sources of noise from a wind turbine include aerodynamic noise (rotating blades in the air)

and mechanical noise (gearbox (if not a direct drive system) and generator).

Noise only occurs above the ‘cut-in’ wind speed and below the ‘cut-out’ wind speed. The typical ‘cut-

in’ wind speed of a modern turbine is 3 meters per second (m/s) and the ‘cut-out’ wind speed is

approximately 25 to 30 m/s. At this stage of the proposal the preferred turbine candidates have not

yet been finalised. For the purpose of this assessment the sound power levels and octave banding

associated with the Nordex N117 3MW turbine were used (this turbine is representative of the

turbine dimensions proposed for the project). Ultimately the most appropriate turbine model and

operating modes will be selected in order to achieve the noise limits set down in the current DoEHLG

Windfarm Planning Guidelines, 2006.

Construction noise will occur during excavation and earth moving, laying of roads and hard

standings, transportation of materials and erection of the wind turbines. The construction phase will

be phased and temporary.

Amplitude Modulation, Infrasound, Wind Farm Noise on Health and Vibration associated with wind

turbines have also been addressed in this report.

The report assesses the impact of the operational and construction phase of the proposed wind farm

against noise guideline thresholds in the current DoEHLG Windfarm Planning Guidelines, 2006.

Vibration, low frequency noise and infrasound are also discussed in brief. These characteristics are

outside the scope of the assessment criteria and methodology in the UK and Ireland.

9.1.1 Methodology

In general the methodology used to assess the noise impact from wind farms includes extended

measurements of the existing background noise levels (across a range of wind speeds) at nearby

representative dwellings and comparisons against the predicted noise output from the wind farm,

which also varies with wind speed. The methodology and planning guidance framework are

described in the following sections.

The report assesses the impact of the operational and construction phase of the proposed wind farm

against noise guideline thresholds in the current Irish Wind Energy Development Guidelines

(DoEHLG, 2006).


9-2

9.1.2 Wind Farm Noise, Policy and Guidance

As with any development a balance must be struck between the noise restrictions placed on a wind

farm, the protection of amenity and the national and global benefits of renewable energy

development. The guidance documents used in the preparation of this report are best practice in

assessing wind farm noise and are outlined as follows:

9.1.2.1 ETSU-R-97 – The Assessment and Rating of Wind Farm Noise (1997)

The assessment was undertaken with cognisance to ETSU-R-97 – The Assessment and Rating of Wind

Farm Noise (1997)1. This document is currently used as the industry standard in the UK and Ireland

and the noise levels contained within the Irish Wind Energy Development Guidelines are adapted

from this document.

9.1.2.2 IOA Acoustics Bulletin Article, Prediction and Assessment of Wind Turbine Noise, March/

April 2009

The Institute of Acoustics Bulletin Vol. 34 no 2 contains an agreement, jointly authored by a number

of consultants working in the wind turbine sector for developers, local authorities and third parties,

on an agreed methodology for addressing issues not covered by ETSU-R-97. This includes a

methodology for dealing with wind shear and an agreed method for noise predictions.

9.1.2.3 A Good Practice Guide (GPG) to the application of ETSU-R-97 for the Assessment and Rating

of Wind Turbine Noise (Institute of Acoustics, 2013).

This publication which was issued by the Institute of Acoustics in May 2013, is endorsed by the UK,

Department of Energy and Climate Change (DECC), the Northern Ireland Executive, the Scottish

Executive and the Welsh Assembly and provides guidance on all aspects of the use of ETSU-R-97. The

assessment presented herein adopts the recommendations of the GPG.

9.1.2.4 Department of the Environment, Heritage, and Local Government (DoEHLG) – Wind Energy

Development Guidelines (Department of the Environment, Heritage and Local Government

2006)

This document provides the framework for wind farm noise assessment in Ireland. The noise limit

thresholds in this publication are those currently endorsed by the Irish Government and deemed to

strike the balance between the protection of residential amenity and renewable energy

developments.

1 A recent research report published by Hayes McKenzie reviewed the way noise assessments are being carried out as part

of the application process for planning consent for wind turbines in England. It was reported that from the sample set

reviewed the ETSU-R-97 methodology has been universally adopted for the assessment of noise from proposed wind farm

developments with 100% of cases stating it to be the appropriate guidance.


9-3

9.1.3 Construction Noise – Policy and Guidance

There are no mandatory noise limits for construction noise in Ireland. The most recent revision of BS

5228-1:2009 Code of practice for noise and vibration control on construction and open sites outlines

noise thresholds for significant impacts.

9.1.4 Survey Methodology

9.1.4.1 Prevailing Background Noise Levels

For the purpose of this assessment noise monitoring was carried out for periods of ten days to two

weeks at each of the measurement locations between January and March 2016. Noise monitoring

was undertaken at 11 locations (NM1 to NM11) which were selected to be representative of the

dwellings closest to the proposed development. Appendix 9-B to this report contains details

(including photographs) on each of the noise monitoring locations. The monitoring equipment used

included:

a) A series of Larson Davis 831 sound level meters were used to measure background noise

levels at the selected receptors. The microphone was mounted on a tripod at least 3m away

from any reflective surfaces and at height of 1.2 meters (m). A specially adapted wind shield

was mounted on the microphone. An outdoor environmental noise enclosure protected the

equipment from the elements.

Plate 9-1 Example of noise meter set up (see also Appendix 9-B)


9-4

b) A Spectrum Data Logging Rain Gauge developed by Specware Technologies was used to

monitor rainfall rate throughout the measurement period. This data was logged in 10

minute intervals which were synchronised with the sound level meters. Measurements

should not be used from periods of heavy rainfall when noise levels will be high due to the

noise of the rain itself and more importantly due to the increased water flow in nearby

streams and rivers. For the purpose of this assessment where rain was recorded the data

point was removed.

Plate 9-2 Spectrum Rain Gauge Data Logger installed on site

c) Wind speed measurements were recorded using on site anemometry masts with

anemometers at varying heights which allowed for the determination of wind shear across

the site. The location of the anemometry mast can be seen on Figure 9-1.


9-5

9.1.4.2 Wind Farm Noise Predictions

The noise modelling software (Predictor, Version 7.1) is based on ISO 9613-2:1996 Acoustics –

Attenuation of sound during propagation outdoors – Part 2: General method of calculation. Research

has demonstrated that this standard in particular which is widely used in Ireland and the UK provides

realistic predictions of noise from on-shore wind turbines during worst case propagation conditions.

This software was used to predict wind farm noise at all dwellings within 1 kilometre of the

proposed wind turbines. The data input into the model was defined by the IOA GPG, 2013. The data

used in the model is conservative in particular as it assumes all dwellings are downwind of all

turbines simultaneously, which in practice cannot happen. For wind directions other than

downwind, noise levels will be lower. A safety margin of 2 dB(A) has been included in the results.

This accounts for the uncertainty in the measurement of the warranted wind turbine sound power

levels.

The predicted turbine noise LAeq has been adjusted by subtracting 2dB(A) to give the equivalent LA90

as suggested by ETSU-R-97.

Table 9-1 Model Input Data

Item Description

Turbine Nordex N117 3MW

Turbine Locations GPS Co-ordinates

House Locations Site Survey, Aerial Photography

Acoustic Emission Acoustic Specification Document

Hub Height 91 m

Topography Flat Earth

Ground Factor Mixed (0.5)Note 1

Receptor Height 4 m

Wind Direction Downwind

Relative Humidity 70%

Temperature 10⁰C

Note 1: The ground factor may be between 0 and 1, were 0 represents hard ground and 1 represents

soft ground. Hard ground reflects sound and soft ground absorbs it.

The sound power levels for the Nordex N117 3MW, with typical octave band data was obtained from

the Nordex Specification Document provided by Nordex and outlined in Table 9-2. This is not to say

that this will ultimately be the final turbine candidate. However it is representative of the size, noise

output and power generating capacity of the likely final turbine selection. Including the margin of

safety/ uncertainty of 2dB(A), a maximum sound power level or noise output of 107dB(A) has been

considered in this assessment.


9-6

Table 9-2 Nordex N117– Octave Banding and Sound Power Levels (SPL)

Wind Speed Octave Band (Hz)

63 125 250 500 1000 2000 4000 8000 SPL dB +2 dB

10 + m/s 83.5 90.5 95.3 96.9 99.8 98.7 96.3 86.2 105.0 107.0

9 m/s 83.5 90.5 95.3 96.9 99.8 98.7 96.3 86.2 105.0 107.0

8 m/s 83.5 90.5 95.3 96.9 99.8 98.7 96.3 86.2 105.0 107.0

7 m/s 83.5 90.2 95.1 96.6 99.1 98.0 95.9 86.1 104.5 106.5

6 m/s 81.8 88.9 93.2 95.1 97.9 97.6 96.2 84.7 103.5 105.5

5 m/s 79.1 90.4 90.6 92.4 95.3 95.8 94.2 83.0 101.5 103.5

4 m/s 74.6 85.9 86.1 87.9 90.8 91.3 89.7 78.5 97.0 99.0

3 m/s 71.6 82.9 83.1 85.9 87.8 88.3 86.7 75.5 94.0 96.0

Note 1: Source (F008_244_A04_EN, Revision 03)

Note 2: +2dB = Inclusion of safety margin

9.1.4.3 Noise Limits and Assessment Criteria

The noise limits applied to the nearest dwellings were adopted from the Department of the

Environment Heritage and Local Government– Wind Farm Energy Planning Guidelines (DoEHLG,

2006).

The impact of the construction works on the local dwellings has also been predicted. The

construction works will be of short duration. Higher noise limits apply to the construction works as

there must be a compromise between the practicality of construction and the temporary nature of

the works.

9.1.4.3.1 Operational Phase Limits

The limits set out in the Department of the Environment Heritage and Local Government (DoEHLG) –

Wind Farm Planning Guidelines were adopted for the purpose of this assessment. The noise limits

have been defined as shown in table 9-3.

Table 9-3 Day and Night Time Noise Limits

Daytime Night time

Where the prevailing background noise level is less than

30dB(A), the greater of 35 - 40dB(A) or plus 5dB above

background

Or

Where the prevailing background noise level is greater than

30dB the noise limits are the greater of 45dB(A) or plus

5dB(A) above background.

the greater of 43dB(A) or plus

5dB(A) above background

For the purpose of this assessment where the prevailing background noise level is less than 30dB(A),

the greater of 40dB LA90 or plus 5dB(A) above background has been adopted.


9-7

9.1.4.3.2 Construction Phase Limits

There are no mandatory noise limits for construction noise in Ireland. The most recent revision of BS

5228-1:2009 Code of practice for noise and vibration control on construction and open sites outlines

noise thresholds for significant impacts. These are outlined in Table 9-4.

Table 9-4 Threshold of significant effect at dwellings

Assessment category and threshold Value Period (LAeq) Threshold value in decibels (dBA)

Category A

Night time (23.00 – 07.00) 45

Evening and Weekends 55

Daytime (07.00 – 19.00) and Saturdays (07.00-13.00) 65

Table 9-5 can be used as follows: for the appropriate period (night, evening/weekends or day), the

ambient noise level is determined and rounded to the nearest 5 dB(A). This is then compared with

the total noise level, including construction. If the total noise level exceeds the appropriate category

value, then a significant effect is deemed to occur.


9-8

9.2 EXISTING ENVIRONMENT

This section describes the existing environment in terms of the noise monitoring locations and the

existing noise sources at these locations contributing to the existing prevailing background noise

levels.

The wind farm is to be developed in a rural area west of Ballydesmond Village, County Kerry. The

main sources of noise in the area and the existing noise environment include traffic on the local and

regional road network, agricultural activity, forestry related activity and other noise typically

associated with a rural location.

9.2.1 Noise Monitoring Locations

There are several one off houses in the vicinity of the wind farm. Given the spatial extent of the wind

farm noise monitoring was undertaken at 11 locations around the wind farm. A representative

dwelling, as the nearest to each turbine was selected. If the noise threshold criteria can be achieved

at these locations they will be achieved at locations further afield. Details of the noise monitoring

locations can be seen in Appendix 9-B. Noise predictions were undertaken for all dwellings within 1

km. The noise contour maps included in this report show all dwellings within 1 km.

The noise monitoring locations and all dwellings within 1km of the proposed wind turbines are

illustrated in figure 9-1.


9-9

Figure 9-1 Noise Monitoring Locations and Dwellings within 1 km


9-10

9.2.2 Derivation of Prevailing Background Noise

The variation in background noise level with wind speed was determined by correlating LA90,10min

noise measurements taken over a period of time with the average wind speeds measured over the

same 10-minute periods and then fitting a curve to this data. The derived regression line (line of best

fit) is the average background noise which occurs under different wind speed conditions. This

process was repeated for the day and night time periods. The graphs in Appendix 9-A illustrate the

prevailing background noise levels across a range of wind speeds as derived from the noise

monitoring period at each of the monitoring locations.

The purpose of data analysis is to provide a representative background noise level across a range of

wind speeds for the daytime amenity and Night time hours and thereby define appropriate noise

limits for a proposed wind energy development. ETSU-R-97 requires the filtering of noise, wind and

rain data for the Amenity and Night time hours.

Daytime Amenity hours are defined as Night time Hours are defined as:

18:00 – 23:00 hrs Monday to Friday 23:00 – 07:00 (weekend and weekday)

13:00 to 18:00 Saturday and 07:00 to 18:00 Sunday

The operational noise limit is derived from the prevailing background noise level. In accordance with

the guidelines the higher of either the lower fixed value (LA90, 45dB by day and 43dB by night) or

the 5 dB margin above the background is applied. At wind speeds where the existing background

noise level is below LA90 30 dB, a lower fixed daytime limit of LA90 40 dB is applied. The night time

lower limit remains fixed at LA90 43dB.


9-11

Table 9-5 Prevailing Daytime Background Noise Levels (45dB(A) or 5dB(A) above the background)

Location Operating Wind Speeds (m/s)

N1

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

Level(LA90 dB)

27 29 32 34 37 40 43 46 49 53

Operational Limit

(LA90 dB) 40 40 45 45 45 45 48 51 54 58

N2

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

32 32 33 34 36 37 39 41 42 45

Operational Limit

(LA90 dB) 45 45 45 45 45 45 45 46 47 50

N3

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

29 30 32 34 36 39 41 44 47 50

Operational Limit

(LA90 dB) 40 45 45 45 45 44 46 49 52 55

N4

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

31 32 33 34 36 38 40 43 46 49

Operational Limit

(LA90 dB) 45 45 45 45 45 45 45 48 51 54

N5

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

28 28 30 31 36 38 39 42 46 50

Operational Limit

(LA90 dB) 40 40 45 45 45 45 45 47 51 55

N6

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

33 33 34 35 36 38 40 42 45 48

Operational Limit

(LA90 dB) 45 45 45 45 45 45 45 47 50 53

N7 Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12


9-12

Prevailing

Background Noise

(LA90 dB)

29 29 31 32 34 34 37 40 42 45

Operational Limit

(LA90 dB) 40 40 45 45 45 45 45 45 47 50

N8

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

35 35 36 36 38 39 41 42 44 47

Operational Limit

(LA90 dB) 45 45 45 45 45 45 46 47 49 52

N9

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

33 33 33 34 35 36 38 40 42 44

Operational Limit

(LA90 dB) 45 45 45 45 45 45 45 45 47 49

N10

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

32 34 36 38 40 44 46 50 53 57

Operational Limit

(LA90 dB) 45 45 45 45 45 49 51 55 58 62

N11

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

32 32 34 34 36 37 40 42 44 47

Operational Limit

(LA90 dB) 45 45 45 45 45 45 45 47 49 52


9-13

Table 9-6 Prevailing Night Background Noise Levels (43 dB or 5dB above the background)

Location Operating Wind Speeds (m/s)

N1

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

Level(LA90 dB)

23 27 31 34 38 41 41 44 49 52

Operational Limit

(LA90 dB) 43 43 43 43 43 46 46 49 54 57

N2

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

33 34 35 36 36 37 38 38 38 38

Operational Limit

(LA90 dB) 43 43 43 43 43 43 43 43 43 43

N3

Wind Speed (m/s) 23 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

23 26 28 31 34 36 39 42 45 48

Operational Limit

(LA90 dB) 43 43 43 43 43 43 44 47 50 53

N4

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

25 27 30 32 34 37 40 43 46 49

Operational Limit

(LA90 dB) 43 43 43 43 43 43 45 48 51 54

N5

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

22 24 26 29 32 35 39 42 46 51

Operational Limit

(LA90 dB) 43 43 43 43 43 43 44 47 51 56

N6

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

29 30 31 33 35 37 39 42 45 48

Operational Limit

(LA90 dB) 43 43 43 43 43 43 44 47 50 53

N7 Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12


9-14

Prevailing

Background Noise

(LA90 dB)

25 27 30 32 34 37 37 39 42 46

Operational Limit

(LA90 dB) 43 43 43 43 43 43 43 44 47 51

N8

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

28 29 30 32 33 35 38 40 43 46

Operational Limit

(LA90 dB) 43 43 43 43 43 43 43 45 48 51

N9

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

27 29 31 33 35 37 39 41 42 44

Operational Limit

(LA90 dB) 43 43 43 43 43 43 44 46 47 49

N10

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

26 31 33 34 36 40 44 47 52 57

Operational Limit

(LA90 dB) 43 43 43 43 43 45 49 52 57 62

N11

Wind Speed (m/s) 3 4 5 6 7 8 9 10 11 12

Prevailing

Background Noise

(LA90 dB)

24 26 28 30 32 35 38 41 44 47

Operational Limit

(LA90 dB) 43 43 43 43 43 43 43 46 49 52


9-15

9.3 LIKELY SIGNIFICANT IMPACTS

9.3.1 Operational Phase of Predicted Results

Noise from the wind farm was predicted at the eleven noise monitoring locations at the greatest

sound power level to represent worst case scenario conditions. A review of the Nordex 117/3000

Acoustic Specification Document (F008_244_A04_EN) states that this is 105.0 dB(A) and occurs at 8

m/s. A further 2 dB has been added to this sound power level in accordance with best practice as a

margin of safety to account for uncertainty when the turbine sound power levels are measured. This

results in a total worst case noise emission of 107dB(A).

Table 9-7 Operational Daytime Noise Immission Levels and Limit Values

Wind

Speed

(m/s)

Operational Noise Immission Levels (LA90 dB)

N1

Day

Lim

it

N2

Day

Lim

it

N3

Day

Lim

it

N4

Day

Lim

it

N5

Day

Lim

it

N6 D

ay L

imit

N7

Day

Lim

it

N8

Day

Lim

it

N9

Day

Lim

it

N10

Day

Lim

it

N11

Day

Lim

it

3 27 40 27 45 30 40 28 45 31 40 29 45 28 40 29 45 30 45 29 45 29 45

4 30 40 30 45 33 45 31 45 34 40 32 45 31 40 32 45 33 45 33 45 32 45

5 35 45 34 45 38 45 35 45 39 45 37 45 36 45 37 45 38 45 38 45 36 45

6 37 45 37 45 40 45 38 45 41 45 39 45 39 45 39 45 39 45 40 45 38 45

7 38 45 38 45 42 45 39 45 42 45 40 45 39 45 40 45 41 45 42 45 40 45

8 39 45 38 45 42 44 39 45 43 45 41 45 40 45 41 45 42 45 42 49 40 45

9 39 48 38 45 42 46 39 45 43 45 41 45 40 45 41 46 42 45 42 51 40 45

10 39 51 38 46 42 49 39 48 43 47 41 47 40 45 41 47 42 45 42 55 40 47

11 39 54 38 47 42 52 39 51 43 51 41 50 40 47 41 49 42 47 42 58 40 49

12 39 58 38 50 42 55 39 54 43 55 41 53 40 50 41 52 42 49 42 62 40 52

Table 9-7 presents the noise immission levels (noise from turbines at receiver/noise sensitive

location) at each wind speed compared to the day time operational limit. It can be seen that noise

from the wind farm is predicted not to exceed the derived operational day time limits at any of the

selected representative locations. This indicates that a wind turbine with similar acoustic

characteristics to the one used for the purpose of this assessment as a likely candidate will operate

within the day time noise limit thresholds set down in the wind energy planning guidelines.


9-16

Table 9-8 Operational Night time Noise Immission Levels and Limit Values

Wind

Speed

(m/s)


N1

Nig

ht

Lim

it

N2

Nig

ht

Lim

it

N3

Nig

ht

Lim

it

N4

Nig

ht

Lim

it

N5

Nig

ht

Lim

it

N6

Nig

ht

Lim

it

N7

Nig

ht

Lim

it

N8

Nig

ht

Lim

it

N9

Nig

ht

Lim

it

N10

Nig

ht

Lim

it

N11

Nig

ht

Lim

it

3 27 43 27 43 30 43 28 43 31 43 29 43 28 43 29 43 30 43 29 43 29 43

4 30 43 30 43 33 43 31 43 34 43 32 43 31 43 32 43 33 43 33 43 32 43

5 35 43 34 43 38 43 35 43 39 43 37 43 36 43 37 43 38 43 38 43 36 43

6 37 43 37 43 40 43 38 43 41 43 39 43 39 43 39 43 39 43 40 43 38 43

7 38 43 38 43 42 43 39 43 42 43 40 43 39 43 40 43 41 43 42 43 40 43

8 39 46 38 43 42 43 39 43 43 43 41 43 40 43 41 43 42 43 42 43 40 43

9 39 46 38 43 42 44 39 45 43 44 41 44 40 43 41 43 42 44 42 49 40 43

10 39 49 38 43 42 47 39 48 43 47 41 47 40 44 41 45 42 46 42 52 40 46

11 39 54 38 43 42 50 39 51 43 51 41 50 40 47 41 48 42 47 42 57 40 49

12 39 57 38 43 42 53 39 54 43 56 41 53 40 51 41 51 42 49 42 62 40 52

Table 9-8 presents the noise emission levels (noise from turbines at receiver/house) at each wind

speed compared to the night time operational limit. It can be seen that noise from the wind farm is

predicted not to exceed the derived operational night time limits at any of the selected

representative locations. This indicates that a wind turbine with similar acoustic characteristics to

the one used for the purpose of this assessment as a likely candidate will operate within the night

time noise limit thresholds set down in the wind energy planning guidelines.

9.3.2 Substation

The proposed southern substation is located at approximately 180 m from the landowner’s house.

The main noise source from the proposed substation will come from the external transformer. For

the purpose of this assessment a noise measurement was taken from a representative substation. A

noise level of 60 dB(A) was measured at 5m, which would result in a worst case of 30 dB at 180 m.

This is unlikely to be audible above existing background noise levels and is below typical night time

noise limit criteria even with a +5dB(A) penalty for the nature of the sound from the transformer.


9-17

9.3.3 Cumulative Impact

There is a permitted wind farm comprising of 15 turbines, under construction, approximately 650 m

west of the proposed Silverbirch Wind Farm. There are two turbines operating at the Munster

Joinery facility approximately 2 km east of the proposed Silverbirch Wind Farm. All other wind farms

in the area (whether existing or permitted but not yet constructed) were assessed and determined

to have no additional impact. A cumulative impact scenario was considered in order to quantify the

cumulative impact of all these wind turbines in operation at the same time.

The additional modelling scenario considered the loudest noise emission wind speed for each

turbine, therefore presenting the worst case scenario. If the noise limit criteria can be achieved

under the cumulative worst case conditions, then there will be no significant cumulative impact.

Table 9-9 Cumulative Operational Daytime Noise Immission Levels and Limit Values

Wind

Speed

(m/s)


N1

Day

Lim

it

N2

Day

Lim

it

N3

Day

Lim

it

N4

Day

Lim

it

N5

Day

Lim

it

N6 D

ay L

imit

N7

Day

Lim

it

N8

Day

Lim

it

N9

Day

Lim

it

N10

Day

Lim

it

N11

Day

Lim

it

8 39 45 39 45 42 44 40 45 44 45 42 45 42 45 41 45 42 45 42 49 41 45

9 39 48 39 45 42 46 40 45 44 45 42 45 42 46 41 46 42 45 42 51 41 45

10 39 51 39 46 42 49 40 48 44 47 42 47 42 47 41 47 42 45 42 55 41 47

11 39 54 39 47 42 53 40 51 44 51 42 50 42 49 41 49 42 47 42 58 41 49

12 39 58 39 50 42 55 40 54 44 55 42 53 42 53 41 53 42 49 42 62 41 52

Table 9-10 Cumulative Operational Night time Noise Immission Levels and Limit Values

Wind

Speed

(m/s)


N1

Nig

ht

Lim

it

N2

Nig

ht

Lim

it

N3

Nig

ht

Lim

it

N4

Nig

ht

Lim

it

N5

Nig

ht

Lim

it

N6

Nig

ht

Lim

it

N7

Nig

ht

Lim

it

N8

Nig

ht

Lim

it

N9

Nig

ht

Lim

it

N10 N

igh

t Li

mit

N11

Nig

ht

Lim

it

8 39 46 39 43 42 43 40 43 44 43 42 43 42 43 41 43 42 43 42 43 41 43

9 39 46 39 43 42 44 40 45 44 44 42 44 42 43 41 43 42 44 42 49 41 43

10 39 49 39 43 42 47 40 48 44 47 42 47 42 44 41 45 42 46 42 52 41 46

11 39 51 39 43 42 48 40 51 44 51 42 50 42 47 41 48 42 47 42 57 41 49

12 39 57 39 43 42 53 40 54 44 56 42 53 42 51 41 51 42 49 42 62 41 52

The results show that the night time limit may be exceeded at N5 at 8 m/s under downwind

conditions. At wind speeds below 8 m/s the night time limit is achieved, and at wind speeds above 8

m/s the night time limit will be achieved as background noise levels will begin to mask the noise. By

operating T5 in a -2dB noise reduced mode under downwind conditions at 8 m/s the noise limit at

N5 can be achieved. The consent of the landowner can also be provided for the location in question.

The results presented in tables 9-9 to 9-10, are worst case scenario and include a safety margin of 2

dB(A). In reality noise levels are likely to be lower than those presented.


9-18

Figures 9-2 and 9-3 below illustrate the worst case noise emissions for the Silverbirch wind farm

stand alone and in combination with other wind turbines in the area. All dwellings within 1 km are

included in the calculation.


9-19

Figure 9-2 Stand Alone Worst Case Noise Emissions


9-20

Figure 9-3 Cumulative Worst Case Noise Emissions


9-21

9.3.4 Potential for Tonal Content

A tone can be described as an identifiable characteristic from a particular sound. It can be commonly

described as a whine hum, hiss or screech. Such characteristics incur an additional acoustic penalty

to the wind turbine noise emission. Typically wind turbines are broadband in nature and there are

no clearly audible tones when operating normally, therefore no penalty has been included.

9.3.5 Vibration and Low Frequency Noise

To date there is no published evidence to suggest a direct link between wind farms and effects on

health. The main publications supporting these views include.

Australian National Health and Medical Research Council (NHMRC) July 2010

“There is currently no published scientific evidence to positively link wind turbines with adverse

health effects”.

Wind Turbine Sound and Health Effects - An Expert Panel Review - American Wind Energy

Association and Canadian Wind Energy Association December 2009

“There is no evidence that the audible or sub-audible sounds emitted by wind turbines have any

direct adverse physiological effects.

The ground-borne vibrations from wind turbines are too weak to be detected by, or to affect,

humans.

The sounds emitted by wind turbines are not unique. There is no reason to believe, based on the

levels and frequencies of the sounds and the panel’s experience with sound exposures in occupational

settings, that the sounds from wind turbines could plausibly have direct adverse health

consequences.”

Renewable UK - Wind Turbine Syndrome - An independent review of the state of

knowledge about the alleged health condition July 2010

“There is no reason to believe that the sounds from wind turbines could plausibly have direct adverse

health consequence”

Spatio-temporal differences in the history of health and noise complaints about

Australian wind farms: evidence for the psychogenic, “communicated disease”

hypothesis. Professor Simon Chapman, University of Sydney, 2013

The paper published in the peer reviewed New Scientist concluded “In view of scientific consensus

that the evidence for wind turbine noise and infrasound causing health problems is poor, the reported


9-22

spatio-temporal variations in complaints are consistent with psychogenic hypotheses that health

problems arising are “communicated diseases” with nocebo effects likely to play an important role in

the aetiology of complaints”.

Systematic review of the human health effects of wind farms, Australian Government

National Health and Research Centre, 2014

This independent review of the literature was commissioned by the National Health and Medical

Research Council (NHMRC) to determine whether there is an association between exposure to wind

farms and human health effects. The review was undertaken by independent reviewers from

Adelaide Health Technology Assessment and the development of the review was guided by NHMRC’s

Wind Farms and Human Health Reference Group.

Direct evidence of any health effects was obtained through a systematic literature review of all the

available evidence on exposure to the physical emissions produced by wind turbines. The emissions

investigated were: noise, shadow flicker and the electromagnetic radiation (EMR) produced by wind

turbines.

A background literature review was also undertaken to establish whether there is basic biological

evidence, or evidence from research into other circumstances of human exposure to the physical

emissions that wind turbines produce, that makes it plausible that wind turbines cause adverse

health effects.

Before the review was finalised, an international expert organisation (independent from the

reviewers) assessed the methodology and quality of the systematic review to ensure it was

conducted in a robust and transparent manner.

Source (https://www.nhmrc.gov.au/guidelines/publications/eh54)

It concluded: “The evidence considered does not support the conclusion that wind turbines have

direct adverse effects on human health, as the criteria for causation have not been fulfilled”.

Wind Health Impacts Dismissed in Court, Mike Barnard, Energy and Policy Institute, August

2014.

In this report, Mike Barnard at the Energy and Policy Institute, catalogues the outcomes of 49

attempts by wind farm opponents to use the courts or tribunals to stop developments. The

report concluded that the courts dismissed all but one of the cases and that case is an outlier

and circumstantial. The report goes on to state: The courts have spoken. Wind Farms do not

cause health problems.


9-23

9.3.6 Amplitude Modulation

The Institute of Acoustics (IOA) in their report titled A Method for Rating Amplitude Modulation in

Wind Turbine Noise published in August 2016, define Amplitude Modulation as:

periodic fluctuations in the level of audible noise from a wind turbine (or wind turbines), the

frequency of the fluctuations being related to the blade passing frequency of the turbine rotor(s).

This characteristic of the sound might be described by a listener as a regular ‘swish’, ‘whoomph’ or

‘thump’, depending on the cause and the severity of the modulation.

There is currently no recognised limit for AM in Ireland or the UK. However, instances of nuisance

arising from AM are rare and, where it has been found to occur, it is limited to very specific sites in

limited wind conditions. AM can be addressed to remove the impacts at a given location by

controlling one or more turbines in the very limited wind conditions where it is found to occur. The

IOA have developed a Reference Methodology for the measurement and rating of AM which can be

used to rate and evaluate complaints, should any arise, and ensure they are adequately mitigated to

remove impacts.

Silverbirch Wind Farm has provided a commitment (see the mitigation section below) to control

turbines such that any issues arising from AM which are evaluated by the IOA Reference

Methodology to be a nuisance will be removed.

9.3.7 Construction Phase

The construction phase entails the building of the wind farm infrastructure including mainly, roads,

hardstandings, turbine bases, drainage system, substations and control buildings and borrow pits.

The main noise sources include heavy machinery and support equipment used to construct the

various elements. This typically means heavy earth moving machinery, generators and material

transport trucks. For the purpose of assessing the likely construction phase impacts, the construction

phase has been separated into two separate categories, 1) General Construction Activities, and 2)

Construction Traffic.

9.3.8 General Construction Activities

This category includes the noise associated with construction and earth moving plant such as

diggers, dumpers and delivery trucks. The construction of the wind farm will be phased and not all

activity will be taking place simultaneously.

The construction of linear infrastructure such as roads and cable trenches is such that it moves along

quickly and plant and machinery do not remain in the one location for long periods of time. The

construction of the substations and turbine bases will require noisy items of plant and machinery to

remain in a fixed location for longer.


9-24

At this stage of the proposal exact details on the number and type of machinery required are not

available. However enough information is available to accurately estimate the likely construction

equipment required.

Table 9-11 below is a typical list of plant and machinery involved in wind farm construction activities.

The noise levels from the equipment identified above have been sourced from BS5228 Noise

Database for Noise and Vibration Control on Construction and Open Sites-1:2008+A1 2014.


9-25

Table 9-11 Sound Power Frequency Data for Typical Construction Plant Machinery

Plant and Machinery Octave Banding (Hz)

Sound

Power

Level

dB(A)

Sound

Pressure Level

@10mdB(A) 63 125 250 500 1k 2k 4k 8k

Telescopic Handler 86.8 86.9 85.4 92.8 98 96.2 88 78.9 102 71

Mobile Crane 84.8 90.9 93.4 90.8 95.0 95.2 88.0 79.9 101 70

30-50T Excavator (x2) 89.8 92.9 99.4 104.8 104 103.2 100 92.9 110 79

15-30T Excavator (x4) 99.8 98.9 104.1 100.8 101 100.2 96 86.9 109 78

12T Roller (x2) 94.8 98.9 99.4 108.8 104 100.2 97 90.9 111 80

Dump truck (x5) 89.8 94.9 99.4 98.8 105 102.2 97 87.9 109 78

Tractor & Trailer (x4) 97.8 100.9 98.4 103.8 104 104.2 96 88.9 110 79

15-20T Rubber Tired

Excavator 78.8 80.9 86.4 91.8 94 92.2 91 79.9 99

68

Erection and Assist

Crane (x2) 70.8 85.9 90.4 89.8 97 98.2 87 75.9 102

71

3-10T mini digger 85.8 86.9 90.4 90 95.0 90 92 84.9 100 69

Rock Breaker 83.8 96.9 103.4 109.8 117 118.2 118 114.9 123 92

Diesel Generator 84.8 88.9 79.4 81.8 84 80.2 77 66.9 92 61

The estimated programme of works for construction indicates an 18 to 24 month period. The

construction works will be sequenced and all the noise sources presented in Table 9-11 will not be in

operation continuously for the duration of the construction phase. However adopting a conservative

approach it has been assumed that they will.

The decibel sum of all of the items of plant listed above totals 94dBA at 10 metres. Using the inverse

square law rule (In decibel terms a doubling (or halving) of sound intensity corresponds to an

increase (or reduction) of 6dB) we can deduce the sound pressure level, or noise impact, as follows:

94dB at 10m

88dB at 20m

82dB at 40m

76dB at 80m

70dB at 160m

64dB at 320m

58dB at 640m

The results of the construction noise predictions indicate that the appropriate construction noise

limit (65dB (A)) as outlined in BS5228-1:2009 will not be exceeded beyond 320 m. Considering that

there are no items of permanent fixed wind farm infrastructure (i.e. turbine/ substation/ control

building) within 450m of any dwelling it is predicted that construction phase noise will not exceed

recommended limits during turbine or ancillary buildings construction. Considering the conservative

nature of the prediction calculation (i.e. attenuation due to distance only and all machinery in


9-26

operation simultaneously) it is predicted that road construction will not exceed the construction

noise limit at any location.

9.3.8.1 Substation Construction

Two substations form part of the overall development. The main substation at Ballynahulla is more

than 600 m from the nearest dwelling, and in accordance with the calculations presented in section

4.3.1, the noise impact will not be significant. The substation at Tooreengarriv is approximately 180

m from the nearest dwelling. The main item of plant and machinery likely to be involved at any one

time is an excavator. Noise immission levels at 160m from such an item of plant is 56 dB(A). The

construction of this piece of infrastructure will be of relatively short duration and in that regard, in

combination with the likely noise emission, the noise impact from the construction of this substation

is not considered significant.

9.3.8.2 Borrow Pits

Three borrow pits will be required for the purpose of providing a supply of stone for the wind farm

construction. The operation of the borrow-pit is likely to potentially have a rock breaker, one large

(30-50T) excavator and one smaller (15-30T) excavator as well as two to three dump trucks

operational at any one time. The decibel sum of these sources at 10m is approximately 93 dB,

reducing to 69 dB at 160m, and 63 dB at 320m.

Borrow pit No 3 at Ballynahulla is approximately 270 m from the closest dwelling located to the

north east of same. When the rock breaker is in operation noise levels may potentially exceed the 65

dB(A) construction noise threshold. However while the rock breaker is not in operation, the

construction noise threshold will not be exceeded. In order to reduce the noise levels the operation

of the rock breaker will be kept to a minimum. Further the working face of the borrow pit will be

used as a barrier to noise propagation towards the nearest dwelling.

There is sufficient separation distance between the nearest dwellings and Borrow Pit No. 1 (500 m)

and No. 2 (460 m) to ensure that the construction noise thresholds are not exceeded.

9.3.8.3 Cable Trench/ Jointing Bays

Works along the public road including cable trenching, construction of cable jointing bays and

junction modifications will be of limited duration and only involve limited plant so noise from these

elements of the works are not anticipated to have a significant impact on nearby dwellings along

these sections of the public road.


9-27

9.3.9 Construction Traffic

On a wind farm the most intense period of construction traffic activity takes place during the pouring

of the concrete for the turbine bases. This is because all the concrete required for a turbine base

must be poured on a single day. A base pour may generate up to 12 HGV (Heavy Goods Vehicles)

movements per hour. Using a conservative approach it is assumed that there will be a further 6

HGVs per hour for other miscellaneous activities.

For mobile items of plant that pass at intervals it is possible to predict an equivalent continuous

sound level using the following expression for predicting LAeq alongside a haul road used by single

engine items of mobile plant:

LAeq = Lwa – 33 + 10log10Q – 10log10V – 10log10d,

Where

Lwa is the sound power of the plant in decibels (dB);

Q is the number of vehicles per hour;

V is the average vehicle speed, in kilometres per hour (km/h)

d is the distance of receiving position from the centre of the haul road, in metres (m)

Therefore

LAeq = 118Note 1 – 33 + 10Log 18 – 10log50 – 10log20 = 67dB.

Note 1: Source, Maximum drive by sound power level (Table C.2 BS 5228 Part 1).

The averaged LAeq over the course of an hour from passing HGV’s (as calculated above) is predicted

to be 67dBA. The base pours will only occur 14 times (14 turbines) and typically these days do not

occur concurrently. In that regard the noise impact from the HGV concrete deliveries is not

considered significant. The noise levels are typical of any HGV traffic which already uses the road.


9-28

9.4 MITIGATION

The computer modelling software has predicted that at one wind speed the night time limit could be

exceeded at one location and for only one particular wind speed, assuming the neighbouring wind

farm is constructed and operational prior to the Silverbirch wind farm. The result is likely an

overestimate (due to conservatisms built into the model) and in reality the limit is unlikely to be

exceeded at this location. However for the purpose of satisfying this outcome, operating wind

turbine T5 in a -2dB noise reduced mode when wind speeds are at 8 m/s at night, under downwind

conditions will bring noise immission levels at the receiver in line with the night time limit criteria,

should this be required. However, the dwelling in question is owed by a landowner who has an

economic interest in the project and who has provided consent to the resulting noise levels.

Best practice in the form of BS5228 –1&2:2009 + A1 2014, Code of Practice for the Control of Noise

and Vibration on Construction and Open Sites will be adopted during the construction phase in order

to minimise the noise generated by construction activities and nuisance to neighbours.

9.4.1 Mitigation for Amplitude Modulation

If a complaint of Amplitude Modulation arises during the operation of the Wind Farm, an

investigation into the phenomenon will be carried out in accordance with best practice. If required,

mitigation measures will be put in place to eliminate any nuisance that is found to occur. These

mitigation measures will be applied during the specific meteorological conditions which causes the

AM to happen and involve one or more of the following:

slowing down or stopping the relevant wind turbine.

altering the pitch of the blades (i.e. changing the amount of rotation of the blade along its

length).

realigning the yaw of the rotor (i.e. changing the angle at which the turbine rotor faces into

the wind).

9.5 RESIDUAL IMPACTS

While noise from wind turbines may be audible at certain locations under certain meteorological

conditions, noise levels are not predicted to exceed the DoEHLG Wind Energy Planning Assessment

Criteria designed for the protection of residential amenity.

9.6 CONCLUSION

An assessment of the likely noise impact of the proposed Silverbirch Wind Farm has been carried

out.


9-29

Typical downwind turbine noise levels at all locations within or just outside one kilometre of the

proposed wind turbines have been predicted based on provided sound power level data for a

Nordex N117 3MW wind turbine. At this stage, the turbine candidate is subject to change, as the

procurement process will not take place until planning permission has been secured. It is standard

practice to base predictions on a candidate model, in this instance the Nordex N117 3MW. This

turbine is indicative of the size and noise output of the turbine under consideration for the site.

Ultimately the most appropriate turbine and operating modes will be selected in order to ensure

that the operational limits specified in this report are not exceeded.

The assessment has been carried out with reference to methodology outlined in ETSU-R-97,

Assessment and Rating of Noise from Wind Farms and results have been compared against noise

levels outlined in the Irish wind farm planning guidelines.

The results show that the predicted wind farm noise levels can adhere to the assessment criteria and

in particular, the DoEHLG Wind Farm Planning Guidelines.

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