castle hill wind farm - gw · standard nzs6803:1999 for construction noise, ... 2.0 glossary of...

Castle Hill Wind Farm

Noise Effects Assessment

21 July 2011

Level 2 Exchange Place 5 Willeston Street

PO Box 25442 Panama Street

Wellington 6146 New Zealand

T: +64 4 499 3016 F: +64 4 472 1493

www.marshallday.com

Note: This document may be reproduced in full but not in part without the written consent of Marshall Day Acoustics Limited Rp001 R07 2010129 Noise Effects Assessment 21July2011.doc of 130

Project: Castle Hill Wind Farm

Prepared for:

Genesis Energy PO Box 17188 Greenlane Auckland 1546

Report No.:

001 2010129

Document control

Status: Issue: Date: Prepared by: Reviewed by:

Draft 001 17 September 2010 MMH

Draft 2 002 24 January MMH

Draft 3 003 20 April 2011 MMH

Draft 4 004 27 April 2011 MMH CWD

Draft 5 005 1 June 2011 MMH CWD

Draft Final 006 15 July 2011 MMH CWD

Final 007 18 July 2011 MMH CWD

Approved 008 21 July 2011 MMH CWD


EXECUTIVE SUMMARY

Project Description

Genesis Energy is seeking all the necessary resource consents to construct and operate a wind farm in the Northern Wairarapa known as the Castle Hill Wind Farm (hereafter referred to as “CHWF”).

Genesis Energy has commissioned Marshall Day Acoustics Ltd to undertake a noise effects assessment to inform the Assessment of Environmental Effects (AEE).

The wind farm would consist of up to 286 turbines. A Turbine Corridor has been proposed, and four Indicative Turbine Layouts have been developed to represent the range of possible turbine sizes that could be used for CHWF. These layouts have formed the basis of the noise predictions in this assessment.

The assessment of turbine noise has progressed on the basis of a worst-case envelope, with respect to turbine noise emission, turbine location, and the balance between turbine size and number of turbines. The assessment of effects presented in this report is based on the highest noise level predicted from the range of available options. The Indicative Turbine Layouts described represents an envelope within which the wind farm can be designed, without producing noise effects greater than described in this assessment.

In addition to the turbines, the project would include two substations, an optional switching station, interconnecting overhead transmission lines, and approximately 170km of Internal Roads.

Construction works forming part of this application would involve upgrades to the local road network as well as the construction of the Wind Farm itself. Construction activities and the traffic generated by these activities would occur over a period of 159 to 354 weeks, depending on the intensity of works.

Assessment Criteria

Construction and operational noise falls under the control of the Tararua District Plan and the Combined Wairarapa District Plan. These Plans refer to New Zealand Standard NZS6803:1999 for construction noise, and refer to NZS6801 (2008 and 1999 versions respectively) and NZS6802 (2008 and 1991 versions respectively) for the assessment of other noise, with a noise limit of 45 dB LA10 at night and 55 dB LA10 during daytime.

These limits can reasonably be applied to normal activities such as substation noise emissions and on-site maintenance activities. However wind turbine noise falls outside the scope of NZS6801 and NZS6802, and instead is assessed using NZS6808. The outdated (1998) version of this standard is referred to by the Combined Wairarapa District Plan, while the Proposed Tararua District Plan refers


to the 2010 version. It is generally accepted that the revised version (2010) is an appropriate means of assessing noise from wind turbines.

This standard recommends a method for measuring noise from wind turbines, and recommends a limit of 40 dB LAeq or 5 decibels above the existing background sound level. In this report this limit will be referred to as the “standard noise limit”.

The standard has provision for a “high amenity noise limit” in special circumstances, which depend on there being provision for a higher-than-normal degree of noise protection specified in the District Plan. This does not occur in either of the District Plans, and as such the standard noise limit is the appropriate limit to apply in this application.

NZS6808:2010 considers the issues of infrasound, vibration, and health effects. The standard concludes that these effects are not significant for wind farms, and that the standard limit provides adequate protection for health and amenity.

This limit applies at “noise sensitive locations”, which are defined in NZS6808:2010 to include dwellings and schools, and other residential spaces which could include nursing homes or hospitals.

We have excluded from consideration any dwellings whose owners have given written consent to the project (CHWF Landowners) and focus instead on those dwellings owned by people not associated with the project (External Residences). The Study Area includes External Residences within 5 km of the Turbine Corridor.

Construction Noise Assessment

At all noise sensitive locations the predicted noise level from construction of the Turbine Foundations and Platforms and substations is well within the construction noise limits.

Noise from road works is within construction noise limits, except at two specific External Dwellings within 50 metres of road works involving significant earthworks.

Construction activities at these sites will likely be of a short duration, and appropriate mitigations may include programming of activities to avoid noise sensitive times, temporary relocation of residents during construction, and temporary noise barriers.

Construction traffic noise would be significant at five dwellings, where noise levels would be higher than experienced under normal day-to-day conditions, and will become a significant part of the noise environment. The duration of these activities will be on the order of months, and during this time the effect of noise at these dwellings may be significant. However the noise levels involved are consistent with those anticipated by the Construction Noise standard NZS6803, and are considered reasonable in the context of their limited duration.


At various External Residences near Internal and External Road construction activities, there will be short-term periods in which noise levels will increase significantly. These activities will occur over a period of days or several weeks at each site, and in some cases (as described in section 6.1.6) special attention will need to be given to noise mitigation. For the brief periods involved in these works, these noise levels are consistent with those anticipated by the Construction Noise standard NZS6803, and are considered reasonable in the context of their limited duration.

Operational Noise: Wind Turbines

The noise level from wind turbines can comply with the standard noise limit in NZS6808:2010 at all dwellings outside the CHWF Site with the appropriate wind turbine selection. In most cases this can be achieved by any wind farm design within the wind farm envelope described in the project description.

At 23 External Dwellings, the predicted noise level is greater than 35 dBA. At these External Dwellings the noise effects have been specifically considered.

At one External Dwelling the noise level from the loudest Indicative Turbine Layout exceeds 40 dBA, but complies with NZS6808:2010 on the basis of a higher noise limit due to high existing background noise level. The other Indicative Turbine Layouts produce less than 40 dBA. The final design will ensure that compliance with the noise standard will be achieved, either by design of the wind farm or by establishing that the elevated noise limit is appropriate over a variety of seasonal variations.

Although at seven External Dwellings the existing background sound level will frequently be clearly audible, the predicted noise levels in all cases are considered to be reasonable.

It should be noted that the assessment provided by NZS6808:2010 is a conservative approach because:

� The noise propagation calculation is based on a worst-case assumption that the assessment point lies downwind of all turbines at the same time;

� The noise emitted from a wind farm varies with wind speed. This noise assessment is based on the highest level of sound from the wind farm, which only occurs at certain wind speeds and thus only occurs some of the time. This contrasts to other noise sources, such as geothermal or hydroelectric generation facilities, which produce noise continuously.

� The sound level predicted by this assessment and compared with the noise limit will not be produced all the time, and in particular will not occur during still conditions when sound levels are low.


Operational Noise: Other Noise Sources

Noise from substations and overhead transmission lines would occur at very low sound levels, and have noise effects which are less than minor.

Noise from operational traffic will be very limited, and the most affected dwelling would experience sound levels of around 46 dB LA10 on occasions. Noise effects from this traffic would be less than minor.

Mitigation

Mitigations have been proposed, including the establishment of a Construction Noise Management Plan and an Operational Noise Management Plan, and the preparation of a Final Noise Assessment Report. These recommendations will ensure that the noise emissions associated with the construction and operation of the CHWF will comply with the relevant noise rules and produce noise effects no greater than described in this report.


Table of Contents

1.0 PROJECT TERMINOLOGY AND GLOSSARY ............................................................................... 9

2.0 GLOSSARY OF ACOUSTIC TERMINOLOGY .............................................................................. 11

3.0 INTRODUCTION ....................................................................................................................... 12

4.0 NOISE PERFORMANCE STANDARDS ...................................................................................... 20

4.1 Horizons Regional Council and Greater Wellington Regional Council ................................. 20

4.2 Tararua District Plan ................................................................................................................ 21

4.2.1 The Operative Tararua District Plan – 1998 ........................................................................... 21 4.2.2 TDC Proposed District Plan as Amended – Nov 2009 ........................................................... 21 4.3 Masterton District Council ...................................................................................................... 23

4.4 Discussion ................................................................................................................................. 25

4.4.1 Construction Noise .................................................................................................................. 25 4.4.2 Non-Turbine-Related Operational Noise ............................................................................... 26 4.4.3 Wind Turbine Operational Noise ............................................................................................ 26

5.0 ASSESSMENT METHODOLOGY ............................................................................................... 28

5.1 Determining appropriate standards ....................................................................................... 29

5.2 Assessment of Existing Noise Environment ........................................................................... 30

5.3 Predicted noise levels from proposed activities .................................................................... 31

5.3.1 Sound Power Levels................................................................................................................. 31 5.3.2 ISO9613-2 Propagation Model ............................................................................................... 31 5.3.3 CRTN Traffic Noise Model ....................................................................................................... 32 5.4 Modelling Assumptions ........................................................................................................... 33

5.5 Evaluation of predicted noise levels ....................................................................................... 33

6.0 CONSTRUCTION NOISE ........................................................................................................... 37

6.1 Construction Noise Predictions .............................................................................................. 37

6.1.1 Turbine Foundation and Platform Construction ................................................................... 37 6.1.2 Quarrying.................................................................................................................................. 40 6.1.3 Concrete Batching Plants ........................................................................................................ 43 6.1.4 Substation Site Construction .................................................................................................. 44 6.1.5 Internal Road Construction ..................................................................................................... 45 6.1.6 External Road Upgrade Works ............................................................................................... 46 6.1.7 Construction Traffic Noise on Internal Roads ........................................................................ 47 6.1.8 Construction of Internal Transmission Lines ......................................................................... 49 6.2 Construction Noise Effects ...................................................................................................... 50


7.0 OPERATIONAL NOISE —WIND TURBINE NOISE .................................................................... 52

7.1 Model Inputs—Sound Power Curve ....................................................................................... 52

7.2 Model Inputs—Frequency Spectrum ..................................................................................... 54

7.3 Model Inputs—Source Location ............................................................................................. 54

7.4 Model Outputs ......................................................................................................................... 55

7.5 Assessment of Turbine Noise Effects ..................................................................................... 57

7.5.1 Dwellings X170, X171 .............................................................................................................. 59 7.5.2 Dwelling X185, X408 ................................................................................................................ 63 7.5.3 Properties X187, X188, X189, X190 ........................................................................................ 68 7.5.4 Dwelling X258 .......................................................................................................................... 75 7.5.5 Dwelling X265, X396, X407 ..................................................................................................... 79 7.5.6 Dwelling X321 .......................................................................................................................... 84 7.5.7 Dwelling X358, X362, X405 ..................................................................................................... 88 7.5.8 Dwelling X377 .......................................................................................................................... 94 7.5.9 Dwellings X378, X379, X380, X391, X392 ............................................................................... 98 7.5.10 Dwelling X397 ........................................................................................................................ 106 7.5.11 Dwelling X403 ........................................................................................................................ 109 7.6 Infrasound and Vibration ...................................................................................................... 112

7.6.1 Infrasound and Low Frequency Sound ................................................................................ 112 7.6.2 Vibration ................................................................................................................................. 112

8.0 OPERATIONAL NOISE—OTHER SOURCES ............................................................................ 114

8.1 Substation Noise Level Predictions ...................................................................................... 114

8.1.1 Model Inputs .......................................................................................................................... 114 8.1.2 Model Outputs ....................................................................................................................... 115 8.2 Overhead Transmission Lines ............................................................................................... 117

8.2.1 33kV Overhead Lines ............................................................................................................. 117 8.2.2 Internal Transmission Line .................................................................................................... 118 8.3 Road Traffic Noise—Operational Stage ............................................................................... 119

8.3.1 Road traffic – External Roads ................................................................................................ 119 8.3.2 Road traffic – Internal Roads ................................................................................................ 119

9.0 RECOMMENDED MITIGATIONS ........................................................................................... 120

9.1 Construction Noise ................................................................................................................ 120

9.2 Operational Noise .................................................................................................................. 120

10.0 CONCLUSIONS ........................................................................................................................ 122

APPENDIX A: TYPICAL SOUND LEVELS .................................................................................................. 124

APPENDIX B: NOISE PREDICTION MAPS ................................................................................................ 125

APPENDIX C: REFERENCES ...................................................................................................................... 130


1.0 PROJECT TERMINOLOGY AND GLOSSARY

CHWF Castle Hill Wind Farm.

CHWF Landowners Owners of the land on which the wind farm will be built. CHWF Landowners have signed agreements with Genesis Energy.

CHWF Landowners Dwellings

Dwellings within the CHWF Site.

External Dwellings Dwellings external to the CHWF Site.

CHWF Site or Site The area of land defined by the land titles covered by agreements.

External Roads Public roads that are planned to be used for traffic associated with the construction and operation of the CHWF and including roads used by Over-weight and Over-dimension Vehicles.

External Transmission Line

The electricity transmission line which connects CHWF to the Transpower national grid.

Indicative Turbine Layouts

Turbine layouts that have been created to represent the range of possible turbine layouts:

� 80M – a turbine layout consisting of 286 Medium Turbines based on a turbine with an 80m rotor diameter.

� 90M – a turbine layout consisting of 262 Medium Turbines based on a turbine with a 90m rotor diameter.

� 100L – a turbine layout consisting of 242 Large Turbines based on a turbine with a 100m rotor diameter.

� 110L – a turbine layout consisting of 186 Large Turbines based on a turbine with a 110m rotor diameter.

Internal Roads

Roads that will be constructed within the CHWF Site for transporting wind farm components and materials within the Site and to allow access around the Site for construction and operational activities.

Internal Transmission Line

The 220kV electricity transmission line that is On-site and connects the main substation to the satellite substation.

Large Turbine Configuration

Any turbine configuration that consists only of Large Turbines with a maximum quantity of 242 turbines.

Large Turbines Turbines that have a maximum tip height greater than 135m but no greater than 155m.

Main Substation The larger of the two substations, located in the southern region of the wind farm.

Medium Turbine Configuration

Any turbine configuration that consists only of Medium Turbines with a maximum quantity of 286 turbines.


Medium Turbines Turbines that have a maximum tip height of 135m.

Off-site Anywhere outside the CHWF Site.

On-site Anywhere within the CHWF Site.

Satellite Substation The smaller of the two substations, located in the northern region of the wind farm.

Study Area The area encompassing noise sensitive locations that have been considered in this noise effects assessment. This area extends 5 km from the edge of the Turbine Corridor.

Switching Station Provides an optional connection point for the External Transmission Line to connect to the Internal Transmission Line as an alternative to connecting at the Main Substation.

Turbine Clusters Groupings of turbines for ease of reference.

Turbine Corridor The area of the CHWF Site in which Turbines can be located.

Turbine Foundations The underground foundation upon which each turbine is based and which keeps the Turbine upright and stable.

Turbine Platform An engineered flat area beside the turbine that will be used for laying out and assembling turbine components and as a hard standing area for construction equipment and vehicles, particularly the construction crane.

Turbines Wind turbine generators consisting of foundations, tower, nacelle and rotor and including all equipment for and associated with the generation of electricity from the wind.


2.0 GLOSSARY OF ACOUSTIC TERMINOLOGY

dBA A measurement of sound level which has its frequency characteristics modified by a filter (A-weighted) so as to more closely approximate the frequency bias of the human ear.

LAeq The time averaged sound level (on a logarithmic/energy basis) over the measurement period (A-weighted).

LA90 The sound level which is equalled or exceed for 90% of the measurement period. LA90 is an indicator of the mean minimum noise level and is used in New Zealand as the descriptor for background noise (A-weighted).

LA10 The sound level which is equalled or exceeded for 10% of the measurement period. LA10 is an indicator of the mean maximum noise level and is used in New Zealand as the descriptor for intrusive noise (A-weighted).

Noise A sound that is unwanted by, or distracting to, the receiver.

Ambient Noise Ambient Noise is the all-encompassing noise associated with any given environment and is usually a composite of sounds from many sources near and far.

Background Sound See LA90.

NZS 6801:1991 New Zealand Standard NZS 6801:1991 Measurement of Sound

NZS 6802:1991 New Zealand Standard NZS 6802:1991 Assessment of Environmental Sound

NZS 6801:1999 New Zealand Standard NZS 6801:1999 Acoustics - Measurement of Environmental Sound

NZS 6802:1999 New Zealand Standard NZS 6802:1999 Acoustics - Assessment of Environmental Noise

NZS 6803:1999 New Zealand Standard NZS 6803:1999 Acoustics – Construction Noise

NZS 6808:1998 New Zealand Standard NZS 6808:1998 Acoustics – The assessment and measurement of sound from wind turbine generators

NZS 6808:2010 New Zealand Standard NZS 6808:2010 Acoustics – Wind farm noise


3.0 INTRODUCTION

Genesis Energy is seeking the necessary resource consents to construct and operate a wind farm in northern Wairarapa, known as the Castle Hill Wind Farm (hereafter referred to as “CHWF”). Genesis Energy has commissioned Marshall Day Acoustics to undertake a noise effects assessment to inform the Assessment of Environmental Effects (AEE) and various resource consent applications for the CHWF.

The CHWF Site (incorporating land where Genesis Energy has agreements for investigation and development of the wind farm) is located 20km east of Eketahuna and Pahiatua, 20km north-east of Masterton and 15km west of the Wairarapa coast north of Castlepoint (Figure 1). The CHWF Site covers an area of approximately 30,000ha.

The CHWF Site is characterised by undulating hills of predominantly pastoral grass, with grazing by sheep and cattle. Stands of native vegetation are located throughout the site, particularly in gullies, with several small forestry blocks scattered across the site. The topography is varied, with elevation ranging from 200m to 500m above sea level.

The CHWF Site is located in a remote area that is sparsely populated. There are six small rural settlements in or around the CHWF area including Tinui, Pongaroa, Alfredton, Makuri, Tiraumea and Bideford. These six settlements had a combined population in 2006 of around 500 people in 110 households1. Masterton (population 18,000), Pahiatua (population 2,600) and Eketahuna (population 460) are the larger townships located within 30kms of the CHWF Site2 (Figure 1).

Key components and features of the CHWF project include:

� A Turbine Corridor: 3,144ha identified as suitable for turbine placement. Turbines will be located within this corridor.

� Turbine Clusters: groupings of turbines for ease of reference.

� Turbine Configurations: up to 286 Medium Turbines (maximum tip height 135m) or up to 242 Large Turbines (maximum tip height greater than 135m but no greater than 155m) or a mixture of Medium and Large Turbines installed within the Turbine Corridor.

� Internal Roads: roads constructed within the CHWF Site for transporting wind farm components, materials and personnel within the Site and to allow access around the Site for construction and operational activities.

1 Statistics NZ 2006 Census 2 Statistics NZ 2006 Census


� Electrical Balance of Plant (EBoP): All electrical structures and equipment related to the collection and reticulation of electrical power around CHWF to the point of connection to the External Transmission Line. Plant includes an Internal Transmission Line, 33kV overhead lines, 33kV underground cables, a Main Substation and Satellite Substation, an optional Switching Station and switch gear huts along with other associated electrical equipment.

� Monitoring masts: up to 16 monitoring masts to collect on-going meteorological information during the operational life of the CHWF.

� External Roads: Public roads near the Site that are planned to be used for traffic associated with the construction and operation of the CHWF and by Over-weight and Over-dimension Vehicles (OW/OD Vehicles).

� Earthworks associated with the construction and maintenance of the CHWF.

� Temporary construction infrastructure: components required for construction of the CHWF including Concrete Batching Plants, Central Laydown Areas, Excess Fill Areas, Contractor Compound, quarrying and crushing facilities and water storage and abstraction facilities.

� Operations infrastructure e.g. operations and maintenance buildings (O&M facilities).

The Turbine Corridor, Turbine Clusters, Internal Roads, Substations and the Internal Transmission Line are shown in Figure 2. External Roads are shown in Figure 3 and construction infrastructure is shown in Figure 4.

The generation capacity of the CHWF is in the order of 600MW. The maximum capacity will be dependent on the type of turbine eventually selected for the site but current site and wind turbine analysis indicates a potential capacity of up to 860MW.

Development of the CHWF may progress in stages, with any first stage being in the order of 300MW. This capacity depends on the wind turbine model selected, but will also depend on other commercial and technical factors.

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Drawing No: Revision

Project No.

Scale: Sheet SizeDesigned Signed Date

Approved Signed Date

Verified Signed Date

Project: Drawn Signed Date

Rev Date Revision Details Drn.

Drawing Title:

Client:

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Aurecon New Zealand LimitedOld Bank Chambers102 Customhouse Quay (PO Box 1591)Wellington New Zealand

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[email protected]

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Genesis Energy anticipates that a number of turbine models will be commercially available at the time of tendering for the CHWF. In order to allow for flexibility in turbine placement (for commercial, environmental and constructability reasons), Genesis Energy is seeking resource consent for a Turbine Corridor enabling a range of turbines to be considered. The Turbine Corridor covers an area of 3,144ha and incorporates all areas within the CHWF Site that have been identified as most suitable for turbine placement. The Turbine Corridor is shown in Figure 2.

Genesis Energy has undertaken an assessment of available turbines and potential suppliers to identify a range of turbines suitable for installation at the CHWF. Two turbine sizes have been established to capture the range of sizes available:

� Medium Turbines have a maximum tip height of 135m

� Large Turbines have a maximum tip height great than 135m but not more than 155m

The size range of suitable turbines has an effect on the number of turbines which can be installed. As the rotor diameter of the turbines increases, the space required between the turbines also increases to avoid energy loss from wake and other effects. This means the optimal quantity and positioning of turbines changes from one turbine model to the next.

Three different turbine configurations have been established to limit the quantity of turbines used.

� Medium Turbine configurations - comprises only Medium Turbines up to a maximum quantity of 286 turbines

� Large Turbine configurations - comprises only Large Turbines up to a maximum quantity of 242 turbines

� Mixed Turbine configurations - comprises a mixture of Medium and Large Turbines.

The Mixed Turbine configuration has been included as there is a potential for different types of turbines to be used within the Turbine Corridor due to the variance in the wind resource across the CHWF Site. In addition, there may be different turbines available for supply at different stages of development. However, the variation between turbines will be minimised where practicable, for example, while the size may differ, very large turbines will not be utilised next to much smaller turbines. To minimise visual differences, the turbines will be off-white in colour and all will have 3 blades. Tubular (not lattice) towers will be used.

Four Indicative Turbine Layouts (two Medium Turbine Layouts and two Large Turbine Layouts) have been developed to represent the range of possible turbine sizes that could be developed at the CHWF Site and to allow environmental assessment where a specific layout is required. The layouts are based on different


rotor diameter sizes to demonstrate the different turbine spacing that could occur within the Turbine Corridor. The parameters of the four indicative layouts are provided in Table 1 below.

Table 1— Turbine Layouts

Turbine Layout Name 80M 90M 100L 110L Indicative Rotor Diameter (m) (may vary up or down) 80 90 100 110

Indicative Hub Height (m) (may vary up or down) 90 90 100 100

Number of Turbines 286 262 242 186

Maximum tip height (m) 135 135 155 155


4.0 NOISE PERFORMANCE STANDARDS

This section describes the various District Plan noise rules that might apply to this application and the means by which appropriate noise levels are set and the extent of any noise effects are determined.

Acoustic amenity in the rural environment involves two regions. At dwellings within the rural zone, peaceful living conditions, particularly during sleeping hours, are to be protected around the home. Away from dwellings, rural amenity is manifested in the ability to carry out production activities, which often produce noise.

Thus the implementations of the RMA regarding noise generally apply at a “notional boundary”, which is defined as a line at some fixed distance (for example 20 metres) from a dwelling in the rural zone. Within this notional boundary, noise protection is similar to that found in Residential zones. Outside this boundary, noise limits are usually set higher or do not apply at all, so that rural production activities can continue unfettered.

Without this distinction, significant areas of production land would need to be set aside as buffers between properties. With the notional boundary concept in place, both neighbours at a given boundary are likely to be able to carry out production activities up to that boundary.

Wind farms are a relatively recent addition to the rural environment. Wind turbines produce noise, the level of which depends on wind speed. In most cases this noise can be considered to have the same effect as any other noise sources, although slightly different measurement methods are required to measure under varying wind conditions.

While normal district plan noise rules apply directly to some elements of wind farms (such as transformers, fans, and vehicles on private roads), and the rules are generally relevant to the noise from wind turbines, special provisions for measurement and assessment are required for the measurement and assessment of turbine noise. This is generally provided for by reference to NZS6808. Where no such reference is included, NZS6808 is taken as the best practice method.

4.1 Horizons Regional Council and Greater Wellington Regional Council

Neither Regional Council has noise rules that apply to this application. However the two District Councils do have noise rules contained in their District Plans.


4.2 Tararua District Plan

4.2.1 The Operative Tararua District Plan – 1998

The Operative District Plan does not specifically reference wind farms.

General noise sources are to be “measured in accordance with NZS 6801:1999 or any successor … and assessed in accordance with NZS 6802:1999 or any successor. Where NZS 6802:1999 does not include the type of noise in question, the appropriate standard or regulation which covers that type of noise shall be used.”

This reference to other standards covering specific noise types applies directly to the use of NZS6808 for wind farm measurement and assessment. This has been successfully applied at other wind farms in the District.

Permitted activity noise sources are controlled by the following limits:

7.00 am - 7.00 pm daily 55 dBA (L10) 7.00 pm - 7.00 am daily 45 dBA (L10) and 75 dBA (Lmax) These noise limits are not to be exceeded at the boundary of any site used for residential activities or, in the Rural Management Area, at a "notional boundary" which is 10 metres from the facade of the nearest dwellinghouse on land held in a separate certificate of title or, if the complainant’s dwellinghouse is on the same certificate of title, at a notional boundary which is 10 metres from the facade of a complainant’s dwellinghouse.

We note that the night-time limit of 45 dBA L10 is the least stringent limit recommended by NZS6802, and it is our opinion that this does not signal a highly –protected area from a noise perspective.

4.2.2 TDC Proposed District Plan as Amended – Nov 2009

Section 5.3.7.4 (g) states that the criteria for assessment include NZS 6808:2010 and NZS 6803: 1999:

(g) The expected noise effects arising from the construction, maintenance and operation of the facility, with particular regard to the impact of noise on existing dwellings and the ability of the proposal to meet any relevant standards such as NZS6808:2010 Acoustics — Wind Farm Noise and the NZS6803:1999 Construction Noise or any subsequent versions of these standards.


Section 5.4.1.2 contains the permitted activity noise criteria which as are follows:

5.4.1.2 Standards

(a) All noise levels shall be measured in accordance with NZS6801: 2008 and shall be assessed in accordance with NZS6802: 2008. Where NZS6802: 2008 does not include the type of noise in question, the appropriate standard or regulation which covers that type of noise shall be used…

7.00 am - 7.00 pm daily 55 dBA (L10)

7.00 pm - 7.00 am daily 45 dBA (L10) and 75 dBA (Lmax)

These noise limits are not to be exceeded at the boundary of any site used for residential activities or, in the Rural Management Area, at a "notional boundary" which is 20 metres from the facade of the nearest dwellinghouse on land held in a separate certificate of title or, if the complainant’s dwellinghouse is on the same certificate of title, at a notional boundary which is 20 metres from the facade of a complainant’s dwellinghouse.

(f) Construction noise shall be measured and assessed in accordance with NZS6803:1999 or any successor and shall not exceed the noise limits recommended therein.


4.3 Masterton District Council

The relevant document is the Combined Wairarapa District Plan (2008).

Wind farm noise effects are specifically considered as follows:

22.1.20 Wind Energy Facilities

(iv) The effects of traffic and vehicle movements.

(v) The actual or potential noise effects of the construction, development and operation of the wind energy facilities, including particular consideration of the special audible characteristics, and the proximity to and effect on settlements or dwellings, and the ability to meet NZS 6808:1998 “Acoustics – The Assessment and Measurement of Sound from Wind Turbine Generators; and other relevant standards such as NZS 6803:1999 “Construction Noise””.

(viii) The cumulative effects of the proposal.

Section 27 “Definitions” of the Combined Wairarapa District Plan Part C-Consent Process contains the following definition:

Noise Emission Level - means a level of sound measured in accordance with NZS 6801: 1999 “Acoustics - Measurement of Sound” and assessed in accordance with NZS 6802: 1991 “Assessment of Environmental Sound” except as expressly provided for in this Plan. Where NZS 6802:1991 does not include assessment of the type of noise in question, one of the following appropriate Standards may be used;

(i) NZS 6805: 1992 Airport Noise Management and Land Use Planning.

(ii) NZS 6807:1998 Noise Management and Land Use Planning for Helicopter Landing Areas.

(iii) NZS 6808:1998 Acoustics – The Assessment and Measurement of Sound From Wind Turbine Generators.

(iv) NZS 6803:1999 Acoustics – Construction Noise.


Section 4.5.2 “Standards for Permitted Activities” of the Proposed Wairarapa District Plan as Amended by Decisions Part A-Environmental Zones 4. Rural Zone contains the permitted activity noise criteria which as are follows:

(f) Noise Limits

(i) The sound level from activities within any site, excluding mobile sources associated with primary production (e.g. tractors, harvesters), shall not exceed the following limits within any measurement time interval in the stated time-frames, when assessed at any point within the notional boundary of any dwelling on any site within the Rural Zone but excluding any dwelling on the property where the sound levels are generated, and at any point within the boundary of any site within the Residential Zone:

Daytime 7.00am – 7.00pm 55dBA L10

Night-time 7.00pm – 7.00am 45dBA L10. 9.00pm – 7.00am 75dBA Lmax

(ii) All sound levels shall be measured in accordance with NZS 6801:1999 “Acoustics –Measurement of Environmental Sound”, and assessed in accordance with NZS 6802:1991 “Assessment of Environmental Sound”.

Construction Noise and noise from other sources are addressed in Part B – District-Wide Issues. Section 21.1.11 states:

21.1.11 Noise

(a) Noise Emission Levels shall be subject to zone rules for noise, and shall comply with the standards below.

(b) General

(i) Sound levels shall be measured in accordance with NZS 6801:1999 “Acoustics –Measurement of Sound”, and assessed in accordance with NZS 6802:1991 “Assessment of Environmental Sound”.

(c) Construction Noise

(i) Construction noise shall be measured and assessed in accordance with NZS6803:1999 “Acoustics – Construction Noise” and shall not exceed the noise limits set out in Table 2 of that Standard for the timeframes stated.


(ii) Provided that the provisions of the standard related to the duration of construction events and the more or less stringent noise limits applicable in such circumstances shall apply.

Note:

Where NZS 6802:1991 does not include assessment of the type of noise in question, other appropriate Standards may be used as specified in the definition for “Noise Emission Level”.

4.4 Discussion

The noise limits which are stated or referenced in the relevant District Plans are summarised as follows.

4.4.1 Construction Noise

Limits on Construction Noise, and methods for its measurement and assessment are controlled by NZS6803:1999 in both District Plans. The relevant limits for projects of long duration are as follows:

Table 2 -- New Zealand Standard 6803:1999 Recommended Upper Limits (dBA) for Levels of Construction Work Noise Received in Dwellings in Rural Areas—Long Term Project

Duration

Period Noise Level (dBA)

Weekdays Saturdays Sundays and Public Holidays

Leq Lmax Leq Lmax Leq Lmax

0630-0730 55 75 45 75 45 75

0730-1800 70 85 70 85 55 85

1800-2000 65 80 45 75 45 75

2000-0630 45 75 45 75 45 75


4.4.2 Non-Turbine-Related Operational Noise

The permitted activity noise limits in both District Plans is stated as 55 dBA L103

during daytime and 45 dBA L10 during night-time.

This limit would apply to steady noise sources such as substations, and to fans or other mechanical plant associated with ancillary buildings. The measurement and assessment of these noise sources would be controlled by NZS6801 and NZS6802 respectively, with regard to the appropriate version of each standard as referenced in the District Plans.

4.4.3 Wind Turbine Operational Noise

Wind Turbine noise is controlled by the methods and recommended noise limits in NZS6808, either by direct reference or by the exclusion of wind turbines from the scope of NZS6801 and NZS6802. There is reference to the 1998 version of this standard in the Combined Wairarapa District Plan , and reference to the 2010 version of the standard in the Proposed Tararua District Plan as Amended by Decisions (2009).

The 2010 version of the Standard contains improvements to the 1998 version which are generally accepted as best practice, and the use of the 2010 version has been recommended in previous applications in the Tararua District by the Council’s noise expert. We therefore consider it appropriate that the 2010 version of the NZS6808 should be applied for setting noise limits, and for measurement and assessment of wind turbine noise.

With respect to the provision in NZS6808:2010 for a high amenity noise limit of 35 dB LA90 or Background + 5 dB at night-time in specific circumstances and under some wind conditions, the CHWF Site does not constitute a “special circumstance” as described in that standard.

� The relevant permitted activity limit (45 dBA L10 night-time in both District Plans) is the least stringent limit available, and cannot be construed as indicative of a highly protected noise environment. In both the Tararua and Wairarapa District Plans, these limits have recently been reviewed and subjected to public comment.

� The Policies and Methods related to environmental quality and amenity in the Tararua District Plan do not propose that a distinct “high amenity” rural residential provision be included. In general the plan seeks to avoid conflict between production activities and residential activities by encouraging residential growth to occur in Urban zones, and by providing a permitted

3 dBA L10 or dB LA10 is a measure of the highest 10% of a measurement period. It is often considered the “average maximum” of that time period. Historically this measure has been used to measure activity noise but in current best practice this is being replaced by LAeq which avoids various difficulties and generally better reflects human response to noise. Wind turbine noise typically has an L10 value around 2 dB higher than its Leq value.


activity limit that, while not overly stringent, achieves a reasonable degree of noise amenity in the rural environment.

� Similarly, the Combined Wairarapa District Plan recognises that conflict can arise between rural lifestyle residential activities and production activities, and seeks to restrict such residential activities, while providing a reasonable degree of protection for rural dwellings. No “high amenity” protection is proposed in this plan.

On the basis of the protections and intentions of the relevant District Plans, there is no indication that any of the properties near the proposed wind farm constitute “special circumstances” as discussed in NZS6808:2010. The resulting recommended noise limit is the conventional 40 dB LA90 or the background sound level plus 5 decibels, whichever is the greater.

Determination of this limit at each noise sensitive location is discussed in detail in Section 7.5.


5.0 ASSESSMENT METHODOLOGY

Noise has the potential to cause adverse environmental effects, and is one factor considered as part of the resource consent process.

The presence of noise does not necessarily constitute an adverse effect. The level and character of noise, and other factors such as the duration, frequency of occurrence, and also the ambient noise environment are factors to be considered in assessing the noise effects.

Noise standards propose measurement and assessment methods which sometimes include limits and thresholds above which noise can produce adverse effects. Methods for assessing noise character and for considering other noise-related factors are also provided in the standards.

In New Zealand, methods for measurement of most noise sources are given by New Zealand Standard NZS 6801:2008 Acoustics – Measurement of Environmental Sound; methods for assessment are given in NZS 6802:2008 Acoustics – Environmental Noise.

Wind farms present slightly different requirements for measurement as they only operate in the presence of wind, which affects the measurement techniques and the appropriate noise limits. For this reason a standard, NZS 6808:2010 Acoustics – Wind farm noise has been specifically prepared to describe methods for measurement and assessment of operational noise from wind turbines.

Noise from temporary construction activities is also assessed under different guidelines, permitting higher noise levels for limited periods of time. This assessment, along with guidance for construction noise level prediction, is given by NZS 6803:1999 Acoustics – Construction Noise.

It is generally agreed that compliance with the limits recommended by these standards produces an appropriate degree of amenity and health protection for the majority of those exposed. It is not intended that noise levels will be undetectable, nor that the noise environment will not change as a result of new noise sources. However it is understood that the resulting noise levels will not be unreasonable.

In the pre-lodgement stages of a project such as a wind farm, these noise standards are used to assist the project design such that a design may be proposed which complies with the relevant noise standards. Thus an Assessment of Environmental Noise Effects report submitted with an application will generally have already considered the reasonableness of noise effects, and be able to state whether any noise effects are proposed which are above these standards.


The assessment of noise effects from a wind farm consists of the following:

� Determining appropriate standards;

� Measuring the existing noise environment and establishing noise limits;

� Prediction of noise levels from proposed activities;

� Evaluation of the predicted noise levels in light of the relevant standards and the existing environment.

This section describes the means by which the above steps have been carried out in this assessment.

5.1 Determining appropriate standards

Noise standards are in the first instance determined by review of the relevant District Plans. In some cases, District Plan rules directly apply to the noise sources in question. In other case, District Plan rules may provide guidance as to appropriate levels of protection from noise effects.

As described in Section 4 of this report the relevant District Plans refer to New Zealand Standards NZS 6801 (measurement of noise), 6802 (assessment of noise), 6803 (assessment of construction noise) and 6808 (assessment of wind turbine noise). These standards provide further guidance on the specific steps to be taken in the prediction, measurement and assessment of potential noise sources.

In some cases the applicable noise limits depend on conditions discovered during the assessment, such as the construction noise limits which depend on the likely duration of the construction, or the wind turbine noise limit which depends in part on the existing background noise of the environment.

At some wind farm hearings, the issues of very low frequency sound (infrasound) and vibration have been discussed. The recently updated NZS6808:2010 offers guidance on these matters in section 5.5 of that standard:

“5.5.2 Claims have been made that low frequency sound and vibration from wind turbines have caused illness and other adverse physiological effects among a very few people worldwide living near wind farms. The paucity of evidence does not justify at this stage, any attempt to set a precautionary limit more stringent than those recommended in 5.2 and 5.3.” [40dB or B/G+5dB and 35dB or B/G+5dB]

“5.5.3 No recommendations for assessing the potential impact of ground-borne vibration are made because such vibration is not perceptible beyond the boundary of the wind farm.”

Further information on vibration, infrasound and other related issues are presented in section 7.6.


5.2 Assessment of Existing Noise Environment

The methods used to understand the existing noise environment depend on the types of noise sources likely to be encountered in the area of interest, and on the periods of time where the project is likely to affect the environment.

Initial visits to the CHWF Site, and review of aerial photography has confirmed that the Site is rural in character, does not have significant industrial noise sources, and generally is distant from busy traffic ways. The noise environment will be dominated by rural production activities and natural sounds, and some traffic noise is likely to occur near roads.

Rural and natural sounds are generally determined by measurement. In general noise assessments it is sufficient to make a number of measurements at representative locations over a period of several days or weeks. However the wind farm noise standard NZS6808:2010 describes specific methods for noise measurements which allow them to reflect the ambient noise environment as a function of wind conditions.

The specific requirements of NZS6808:2010 relating to background noise measurements are that:

� Background sound levels (dB LA90) are made at 10-minute intervals for a period of 10 – 14 days, or long enough to obtain a good representation of the various wind speeds and directions which are typical for the site.

� These measurements are made at locations representative of “noise sensitive locations”4 which lie within the predicted 35 dBA noise contour of the wind farm (the determination of which is described in the following section).

� While the noise measurements are being made, wind speed and direction measurements are taken at the location where wind turbines are planned. These measurements are taken in the same 10-minute intervals as the noise measurements, so it is possible to relate each noise measurement to the wind condition at the proposed wind farm, and hence to the level of noise which would be produced by the wind farm.

4 “Noise Sensitive Locations” are defined in NZS6808:2010 as locations where noise sensitive activities occur, associated with a habitable space or education space in a building not on the wind farm site.


5.3 Predicted noise levels from proposed activities

The prediction of noise levels in general is done by applying “propagation losses” to “sound power levels”.

� Sound power levels are measured values which describe the total amount of noise emitted by a noise source such as a turbine or collection of construction machinery.

� Propagation losses describe the amount of sound which is lost in the path from source to receiver, and are calculated on the basis of the proximity of the receiver to the source, and from information about ground and atmospheric characteristics.

Noise level predictions of wind turbines and other fixed-location activities such as substations and construction machinery are carried out by the use of noise propagation models implemented in SoundPLAN software. In this software, the ISO 9613-2 industrial noise propagation model is used. This is an internationally recognised model which is recommended for wind farm predictions by the current version of NZS6808:2010.

For assessing construction traffic, distributed line sources are modelled within SoundPLAN software using the ISO 9613-2 model.

For assessing changes in long-term road traffic noise, the CRTN steady flow road traffic noise model is used. This model incorporates both the sound power level estimation and the sound propagation portions of sound level prediction.

5.3.1 Sound Power Levels

In the case of wind turbines, the sound power level is provided by manufacturers of wind turbines in the form of an independently conducted noise measurement report. The specific turbines used to represent the wind farm are discussed in Section 7, Operational Noise Effects.

In the case of construction equipment, representative sound power levels are determined from data provided in NZS6803:1999 (Construction Noise) and from equipment which Marshall Day Acoustics has measured during previous projects.

5.3.2 ISO9613-2 Propagation Model

The ISO9613-2 industrial noise model predicts sound pressure level at receiving locations by calculating the sound attenuation due to distance, air absorption, shielding from topographic features and ground absorption, and subtracting these from the measured octave-band sound power spectrum of the sound source.


The numerical value which results from this prediction is expressed as decibels LAeq. In the case of construction noise, this value is directly compared with the LAeq noise limit.

In the case of wind turbine noise, this value is compared against the LA90 noise limit as if it were an LA90 value. In practise the LA90 value tends to be around 2 dB quieter than the LAeq value, which means there is a slight conservatism in the wind farm’s ability to comply with the LA90 noise limit. This conservatism is built into the NZS6808:2010 assessment method.

Noise Parameters – A Brief Overview

Sound levels which vary over time can be represented statistically by single-number values which have been shown to agree well with human response to noise level.

Within a measurement period (such as the 10-minute period used for wind farm analysis), a number of commonly used statistics includes LAmax, LA10, LAeq, and LA90. Each of these parameters is represented by a decibel scale, and is derived from A-weighted sound which mimics the frequency response of human hearing—hence the “LA” designation in each.

LAmax represents the single noisiest event within the measurement period. This is generally not relevant during daytime noise assessment when people respond to “the average noise level”, but is important for sleep disturbance at night.

LA10 represents the sound level exceeded for 10% of the measurement period, and LAeq represents the average sound level. Both of these statistics are used to describe the sound level “when events are occurring”, such as vehicle activity on a road.

LA90 represents the sound level exceeded for 90% of the measurement period. This is referred to as the “background sound level”, and is used to describe the noise environment when transitory events such as vehicle activity cease. In the case of wind farms LA90 allows the relatively steady wind farm noise to be measured in the presence of other transitory noises such as traffic or wind gusts or animal noises.

Typical sound levels are illustrated in Appendix A.

5.3.3 CRTN Traffic Noise Model

The CRTN (Calculation of Road Traffic Noise) traffic noise model estimates the noise level produced by traffic on a series of road segments based on traffic flow, traffic speed, mix of light and heavy vehicles, road gradient and road surface.


The model then calculates environmental propagation effects based on distance from the road, nature of the intervening ground, and sound barriers and reflectors.

The model can be used both to obtain a predicted noise level based on all of the above inputs, and also to predict the change in noise level that occurs when one or more of the above inputs are changed, even if the rest of the inputs are unknown.

5.4 Modelling Assumptions

ISO9613-2 assumes a slight downwind condition in all directions; this provides a conservative scenario for all noise receivers. In contrast, the noise level at a receiver which is upwind from the noise source will be less than predicted by ISO9613-2 because sound does not propagate equally in all directions when wind is present.

For most noise sensitive locations, particularly those near to a wind farm, the prediction provided by this noise model will be higher than actually experienced, because in reality some noise sources will be downwind of the receiver and therefore will contribute less sound than predicted by this method.

The “downwind in all directions” case is the one required to be considered by NZS6808:2010 in the compliance assessment, and is presented in this report as the primary prediction level.

Alongside this value, this report also presents sound levels resulting from the application of an upwind attenuation model, to predict the likely noise levels under the prevailing wind (from the Northwest) and from the direction which causes the lowest noise level. This provides a range of sound levels which will assist in considering the subjective level of sound relative to the existing background sound levels.

For the “upwind corrected value”, the sound level from a source directly upwind from the receiver is attenuated by 10 dB relative to the ISO9613-2 downwind value. No correction is applied to sources within 80 degrees of downwind (meaning that the “downwind” value is retained). Between upwind and 80 degrees from downwind, a linear interpolation between 0 and -10 dB is applied.

5.5 Evaluation of predicted noise levels

The predicted noise levels are compared with the limits of acceptable noise established for the respective noise sources.

For construction noise and non-turbine operational noise sources, this test of acceptability is established within District Plan noise rules. For operational noise from the wind turbines themselves, NZS6808:2010 offers a means of assessment of the acceptability of the noise level as follows.


NZS6808:2010 requires that the L90 noise level at any residential site caused by a wind turbine generator or wind farm should not exceed a limit of the existing background level (L90) plus 5dBA, or 40dBA, whichever is the greater. In carrying out a pre-construction assessment of effects, the predicted LAeq value is to be used to approximate the LA90 value which will be measured post-construction.

This level of 40 dBA has been based on an internationally accepted indoor noise limit of 30 – 35dB LAeq designed to protect against sleep disturbance, and assumes a reduction from outdoors to indoors of 10 decibels with partly open windows. It is noted that this is a conservative approach, as up to a 15 decibel reduction is actually achieved by a typical dwelling, with windows open approximately 200-300 mm.

The portion of the limit which depends on existing background sound level recognises that in the presence of wind, noise levels increase due to vegetation and other objects with which wind interacts, which typically results in a natural increase in noise levels.

Wind turbine noise is usually most noticeable during lower wind speeds of 6–8 m/s (22–29 km/hr) when the sound level produced by the wind farm can be comparable to, or greater than, the background noise generated by the wind. At higher wind speeds, the background noise due to the wind itself can partially mask the turbine noise, and this forms the basis for the increasing noise limit when the pre-installation background noise level increases with wind speed.

To assess wind farm noise against this limit, measurements of pre-installation background noise level are plotted against measured wind speed. A regression line through these measurement points is used to represent the pre-installation noise level, and the corresponding noise limit is derived from this line.

The predicted wind farm noise level can then be compared against this noise limit line, and if the limit is exceeded, redesign of the wind farm or other mitigation measures are considered.


An example of a measurement of background noise and wind speed is given in Figure 5. In this case note that the background sound level appears to be controlled by steady noise sources below 8 m/s, and begins to rise along with increased wind speed above 8 m/s.

y = -0.00072816x4 + 0.02663429x3 - 0.22507508x2 + 0.72800974x + 28.29451358R² = 0.86533098

0

10

20

30

40

50

60

0 5 10 15 20 25

Mon

itore

d LA

90 (1

0min

) (dB

)

Wind farm wind speed at hub height (m/s)

Measured Noise vs Wind Speed

Figure 5—Typical Background Noise Measurement

The resulting comparison of predicted wind farm noise relative to wind speed against the background sound regression line and the corresponding noise limit is shown in Figure 6.

Figure 6 compares several relationships:

� The green line describes the regression line determined from measurements, as shown in Figure 5.

� The red line describes the noise limit derived from the background noise curve and the fixed 40 dBA portion of the noise limit

� The dark blue line describes the predicted noise level, on the artificial assumption that the receiver lies downwind of all turbines simultaneously.

� The light blue line describes the predicted noise level under the wind direction which produces the lowest sound level—the “best case” situation.

� The dashed purple line describes the predicted noise level under the prevailing wind conditions, when the wind blows from the northwest.


0

10

20

30

40

50

60

0 5 10 15 20 25

Soun

d Pr

essu

re L

evel

(dBA

)


Noise Limit Curves

Limit Background

Wind Farm - Downwind All Directions Wind Farm - Prevailing Wind

Wind Farm - Upwind

Figure 6—Typical Turbine Noise Assessment

In this example the noise limit is determined by the “40 dB LA90” part of the rule below 12 m/s, and by the “background + 5 dB” part of the rule above 12 m/s. The blue line takes the shape of the particular wind turbine’s noise level / wind speed relationship. The peak level which occurs around 11 m/s is the level used to describe the sound level of the wind farm when presented numerically.

In the above example it can be seen that the predicted noise level from the wind farm at this particular site is, at all wind speeds, less than the noise limit. If the dark blue line lies above the red line at any point, it would indicate non-compliance at the wind speeds where this occurs.

It should be noted that compliance with NZS6808:2010 noise limits does not indicate inaudibility of the wind farm. Under some circumstances the wind farm may be the dominant noise source in the environment. In other circumstances the wind farm may not be dominant but would still be audible. In other circumstances the wind farm may in fact be inaudible.

However whether dominant or simply audible, the noise levels produced by wind farms which comply with this limit are said by NZS6808:2010 to be acceptable, and of sufficiently low level to avoid sleep disturbance, intrusion on normal activities, or to cause any adverse health effects.

Comment is provided on the likely change to the noise environment resulting from the predicted noise level from the turbines, relative to the measured background sound level.

It is important to remember that an assessment of wind turbine noise using NZS6808:2010 is using this worst case ‘downwind in all directions’ prediction model. However in most cases the actual noise level experienced from the operational wind farm will very rarely (if ever) reach these levels. The impact of this conservatism on each assessed dwelling is discussed in Section 7.5.


6.0 CONSTRUCTION NOISE

This section describes the inputs, assumptions, and outputs associated with the prediction of noise from construction noise, and considers the effects of construction noise and appropriate mitigations.

6.1 Construction Noise Predictions

Noise modelling, as described in section 5.3, has been carried out to estimate the noise level from construction activities. In the following sections we separately address the most significant construction activities:

� Construction of Turbine Foundations and Platforms

� Quarrying

� Construction of Internal Roads

� Construction of substations

� External Road upgrades

� Construction traffic noise on Internal Roads

� Construction of Internal Transmission Lines

6.1.1 Turbine Foundation and Platform Construction

During Turbine Foundation and Platform construction the dominant noise sources will involve the following:

� Large Bulldozer or Scraper

� Loader

� Dump trucks

� Trucks delivering turbine components

Prediction of noise levels at this stage of construction is carried out by calculating the noise level resulting at each dwelling when the above collection of construction equipment operates at each turbine site.


The sound power levels used for the assessment are as follows:

Table 3—Turbine Platform construction equipment sound power levels

Octave Band Frequency (Hz) A 63 125 250 500 1000 2000 4000 Bulldozer/Scraper 113 117 111 105 109 106 105 105 Loader 110 114 115 108 106 105 103 97 Dump trucks x 3 116 102 109 117 114 111 105 100 Trucks delivering turbine components 98 98 98 96 95 94 90 85

Total Platform Construction Package 118 119 117 118 116 113 109 107

The maximum sound level received by all External Dwellings across all the Turbine Platforms is less than 45 dB LAeq, which is the most stringent (night-time) limit for construction noise specified in NZS6803:1999.

As an indication of the noise levels predicted, the external noise sensitive locations where predicted construction noise levels are greater than 30 dBA LAeq are listed in Table 4. These values relate to noise produced by the construction of the Turbine Platform producing the highest level of construction noise at the particular receiving location.


Table 4—Predicted Turbine Platform Construction Noise Levels

Residence Number

Maximum Predicted Noise Level —dB LAeq

X170 32 X186 33 X187 36 X188 36 X189 36 X190 34 X209 31 X258 31 X263 30 X264 30 X265 40 X321 31 X358 31 X359 31 X361 32 X362 30 X377 32 X378 30 X379 33 X391 30 X392 32

At all noise sensitive locations, the predicted noise from Turbine Foundation and Platform construction activities complies by a very large margin with the daytime construction noise limits, and complies with night time construction noise limits by at least 5 decibels.


6.1.2 Quarrying

A number of locations have been identified within the Study Area where quarrying of construction materials may occur. These are described in material provided by Genesis Energy.

The construction noise standard excludes ongoing quarrying activity from consideration as a construction activity. However quarrying activity which is part of a construction site, and has duration strictly limited to the period of construction of the project which the quarry is supplying, should be assessed using NZS6803.

On the other hand, quarries which are independently established and which operate for a period before or after the defined construction period of the project in question, must comply with district plan noise limits for permitted activities, or according to any specific consent conditions they may have been granted. In this case NZS6801/NZS6802 would be used for the noise assessment.

We have evaluated the sound level from quarrying activities on the basis that the activity involves a large bulldozer, large excavator, a loader, a quarry dump truck, and a crushing plant. The total sound power level for this equipment is 120 dBA.

These sites are generally located amongst turbine sites, and noise from this quarrying operation may regarded as having similar level and noise effect to the noise levels and effects described in the preceding section concerning Turbine Foundation and Platform construction.

This occurs near the following turbines (using the 80M Indicative Turbine Layout numbering):

Turbine Cluster B: B056

Turbine Cluster D: D135, D152, D155, D166

Turbine Cluster G: G208, G222

From these sites, the same conclusion regarding noise effects from quarries may be drawn as for Turbine Foundation and Platform construction: The maximum sound level received by all External Dwellings across all the quarry sites near turbines is less than 45 dB LAeq, which is the most stringent (night-time) limit for construction noise specified in NZS6803:1999. This also complies by a very large margin with the daytime construction noise limits.


One possible quarry location has been identified away from the turbine sites, at NZMG coordinates E2765950 N6059660, as shown in Figure 7.

Figure 7—Possible Quarry Site

This site is located approximately 1500 metres from the nearest External Dwelling, X190. The sound level predicted for X190 is 38 dB LAeq, ignoring any attenuation by the hill which intervenes between the quarry and this property. This topographic attenuation would likely decrease the noise level by a further 10 – 15 decibels. Excluding this attenuation from the calculation allows us to conclude without dependence on position within the quarry that the sound level will be less than 38 dB LAeq.

Noise from quarrying activities at all potential on-site quarry locations will comply with construction noise limits at all times, including the 45 dBA night-time noise limit.


Two additional existing quarries have been identified as shown in Figure 8. These are near to External Residences X168 and X170. In both cases these dwellings lie approximately 260 metres from the quarry site.

Figure 8—Existing Quarries

The predicted sound level from quarry activities at these dwellings is 59 dB LAeq, without regard for any terrain shielding. We have not assessed the noise level of any existing quarry activities, nor have we considered any rights granted to these operations by existing consents.

We note that this sound level easily complies with daytime construction activity noise limits, but that at established quarries engaged in ongoing quarrying it is likely that construction noise limits would not apply. The relevant noise limit in this case would be either the daytime permitted activity noise limit of 55 dBA L10 or another limit described in the consent for the particular quarry.

It is likely that compliance with the permitted activity noise limit would require a modest amount of noise mitigation, to cause a reduction in noise level of 4 decibels. These mitigations may already be present in the current quarry design.


6.1.3 Concrete Batching Plants

Concrete batching will be carried out at one or two locations at any one time. The location of these plants will either be amongst the Turbine Platform sites or near the water take sites.

We have assessed the sound level of concrete batching on the basis of a measured 114 dBA sound power level. Noise from this concrete batching operation may be regarded as having similar level and noise effect to the noise levels and effects described in the section concerning Turbine Platform construction.

To assess noise from the potential water take sites, we have considered the three locations which have been identified in material supplied by Genesis Energy. The location of these sites and the corresponding noise level at the nearest dwelling are listed in Table 5.

Table 5—Concrete Batching Noise from Water Take Sites

Nearest External Dwelling

Distance to Dwelling

Predicted Noise Level

X290 690m 42 dB LAeq



The noise level from concrete batching is predicted to comply with the construction activity noise limit in NZS6803:1999 at all sites during daytime hours, by a significant margin.

At the site near X290, and at all sites near Turbine Platforms, concrete batching is also predicted to comply with night-time construction noise limits.


6.1.4 Substation Site Construction

Substation construction has been assessed using the sound power level of equipment described in Table 3 (as used to predict Turbine Foundation and Platform construction noise) at each of the proposed substation sites.

Sound levels were predicted at all residential dwellings within 5 km, and are presented for the nearest residential dwellings in Table 6 (Main Substation options) and Table 7 (Satellite Substation).

Table 6 – Construction sound levels at dwellings near Main Substation Options

Sound Pressure Level (dB LAeq)

Dwelling Option 1 Option 2

X171 -- 10

X359 21 --

X360 20 --

X361 15 --

X377 -- 30

Table 7 – Construction sound levels at dwellings near Satellite Substation

Dwelling Sound Pressure Level (dB LAeq)

X186 21

X187 26

X188 26

X189 26

X190 25

At all dwellings and school buildings, construction noise from substations is well below the most stringent construction noise limits, even for night-time activities.


6.1.5 Internal Road Construction

Construction of the Internal Roads will in some places bring construction activities closer than the Turbine Foundations and Platforms to noise sensitive locations. This activity will occur for a relatively short period of time at any given noise-sensitive location, typically in the order of several days, while a portion of roadway near to a dwelling is constructed. At other times, the main source of construction noise would be construction traffic on Internal Roads, which is separately addressed in Section 6.1.7.

Modelling of the construction of these roads has been carried out using the construction equipment described in Table 8 at several distances to provide guidelines for road construction noise effects.

The sound power levels used for the assessment are as follows, expressed as decibels:

Table 8—Road construction equipment sound power levels

Octave Band Frequency (Hz) A 63 125 250 500 1000 2000 4000 Bulldozer/Scraper 113 117 111 105 109 106 105 105 Loader 110 114 115 108 106 105 103 97 Offroad Dump Truck 111 97 104 112 109 106 100 95 Road-going Truck 98 98 98 96 95 94 90 85 Total Road Construction Package 116 119 117 114 113 111 108 106

The above package of construction equipment would produce 70 dB LAeq, the maximum allowable during daytime construction activities, at a distance of approximately 50 metres from a receiver location. Beyond this distance the predicted level of construction activities is less than the daytime construction noise limit.

We have not identified any External Dwellings which fall within 50 metres of internal road construction sites, and this is unlikely to occur because Internal Roads are Onsite..

During the short period of construction, we recommend that appropriate noise mitigations be considered on a case-by-case basis as part of the Construction Noise Management Plan prepared for the particular phase of construction.


6.1.6 External Road Upgrade Works

Road works to External Roads beyond Alfredton are not included in this consent, and have not been considered as part of this assessment.

Road works to External Roads from Alfredton to the Site are part of the current consent. A number of areas have been identified where road improvements may be necessary. These works will be subject to meeting the noise limits contained in NZS6803, and typical construction methods are capable of meeting these limits.

In cases where particular circumstances arise where construction activities would exceed these limits, particular consideration will need to be given to appropriate mitigations for residents or other noise sensitive activities in the vicinity of the works.

Using the same methodology as in Section 6.1.5 for Internal Road Works noise, we have determined that such works within 50 meters of dwellings may exceed the Construction Noise Limits in NZS6803, and thus would require mitigation.

Specific dwellings where buildings fall within 50 metres of road works involving significant earthworks are as follows:

1. External Dwelling X171 along Castle Hill Road;

2. External Dwelling X359 along Maringi Road.

Construction activities at these sites will likely be of a short duration, and appropriate mitigations may include programming of activities to avoid noise sensitive times, temporary noise barriers, and in extreme situations, temporary relocation of residents during construction.


6.1.7 Construction Traffic Noise on Internal Roads

Noise from construction traffic on Internal Roads (those roads constructed on private property) must comply with the noise limits in the Construction Noise Standard NZS6803:1999. These limits are as stated in section 4.4.1, the relevant limits being:

70 dBA Leq during weekday and Saturdays from 7.30am – 6pm;

65 dBA Leq during weekday evenings 6pm – 8pm;

55 dBA Leq weekday mornings 6.30am – 7.30am and Sundays 7.30am – 6pm;

45 dBA Leq at all other times.

We have applied the methodology discussed in Section 5 to predict the noise levels from construction traffic on Internal Roads at dwellings. These are presented as “peak hour” levels, which relate to combined truck movements and construction crew vehicle movements, and “average daily” levels, which relate to truck movements only.

Traffic flows have been taken from the Transportation Effect Assessment Report (Traffic Design Group, 2011). The traffic flows used to model noise effects are as follows:

Table 9—Construction Traffic Flows

Turbine Cluster Peak Hour Light Vehicles Peak Hour Heavy Vehicles

A 83 20

B 83 24

C 83 12

D 83 19

E 83 5

F 83 8

G 83 5

At most dwellings the peak hour construction traffic noise levels are less than the night-time permitted activity noise limit (45 dBA L10, which is equal to approximately 42 dBA Leq for traffic noise).


At a number of dwellings close to the internal road network, construction traffic noise levels are more significant, and the predicted noise levels presented in Table 10 as follows may be compared with the construction noise limits.

Table 10 – Predicted Construction Traffic Noise Levels

Predicted Traffic Noise Levels, dB LAeq

Dwelling Turbine Cluster Peak Hour Average Daily

X209 A 43 38

X247 A 56 51

X248 A 59 54

X249 A 62 57

X250 A 54 49

X251 A 53 48

X252 A 53 48

X253 A 51 46

X255 A 50 45

X256 A 51 46

X257 A 48 43

X265 B 48 43

X321 F 51 46

X396 B 48 43

X397 A 68 63

At four dwellings, as listed in Table 10, peak hour construction traffic noise will exceed 55 dB LAeq, and will become a significant part of the noise environment. The duration of these activities will be on the order of months, and during this time the effect of noise at these dwellings may be significant. The noise levels involved are consistent with those anticipated by the Construction Noise standard NZS6803, and are considered reasonable in the context of their limited duration.


6.1.8 Construction of Internal Transmission Lines

The Internal Transmission Line which connects the Main Substation and Satellite Substation (and optionally the Switching Station) generally occurs at distances from dwellings which are similar those associated with construction of the Turbine Foundations and Platforms.

At a number of locations the Internal Transmission Lines and associated pylons will fall nearer to dwellings. This occurs near External Dwellings X186, X187 (and nearby dwellings X188 – X190) and X403.

The sound level from pylon and line construction has been estimated on the basis of the following equipment:

� 20 tonne excavator with auger or drill rig;

� Hiab and concrete trucks;

� Four-wheel drive vehicles.

The sound level predicted at the above dwellings, not including attenuation from any shielding by terrain, is described in Table 11.

Table 11—Internal Transmission Line Construction Noise

Nearest External Dwelling

Distance to Dwelling

Predicted Noise Level

X186 1460m 40 dB LAeq

X187 1400m 40 dB LAeq


At all locations, the predicted noise level from construction of Internal Transmission Lines complies with daytime construction activity noise limits in NZS6803:1999, by a very large margin.

At all receiving locations except for X403, the predicted noise level also complies with night-time construction activity noise limits in NZS6803:1999.


6.2 Construction Noise Effects

The noise from construction activities will in most cases be received in the context of daytime rural activities, characterised by quiet periods dominated by bird and insect noise, stock and dog noise, and wind in vegetation, and punctuated by vehicles and farm machinery.

The ambient sound levels measured at various locations around the Site are described in more detail in the following section concerning operational noise. In general the daytime background sound level at residential sites is around 30 – 40 dB LA90 depending on wind speed, and the daytime activity noise is in the range of 38 – 53 dB LAeq. These spreads are typical of the various sites investigated, and depend more on the intensity of activity on the particular day than on which site is observed.

The effects of noise from construction can be considered against this noise context. The predictions of construction noise given in the preceding section can be summarised as follows:

Table 12—Construction Noise Summary

Construction Activity Typical Sound Level Most Affected

Sound Level

Turbine Foundation and Platform construction

< 35 dB LAeq 40 dB LAeq

Quarrying (On site) < 35 dB LAeq 42 dB LAeq

Quarrying (Off site) 58 dB LAeq 58 dB LAeq

Concrete Batching <35 dB LAeq 62 dB LAeq

Substation construction


Internal road construction

<65 dB LAeq <65 LAeq

External road upgrades

<65 dB LAeq 70 dB LAeq

Traffic noise from construction traffic


Internal Transmission Line Construction

<40 dB LAeq 47 dB LAeq


Noise from machinery (including quarrying and concrete batching) at or near the turbine and substation sites is predicted to be at lower levels than typical daytime ambient noise levels. At most noise sensitive locations construction traffic noise will also be below the ambient noise level. Noise effects from these activities are expected to be less than minor.

Noise from existing Off-site quarries may exceed permitted activity noise limits, but it is likely that mitigations are in place or consent conditions allow elevated noise levels, as these quarries are already established. Any change to the intensity of operation may need to be considered in relation to any existing consent.

At four dwellings, as listed in Table 10, peak hour construction traffic noise will exceed 55 dB LAeq, and will become a significant part of the noise environment. The duration of these activities will be on the order of months, and during this time the effect of noise at these dwellings may be significant. The noise levels involved are consistent with those anticipated by the Construction Noise standard NZS6803, and are considered reasonable in the context of their limited duration.

At various External Dwellings near Internal and External Road construction activities, there will be short-term periods in which noise levels will increase significantly. These activities will occur over a period of days or several weeks at each site, and in some cases (as described in section 6.1.6) special attention will need to be given to noise mitigation. For the brief periods involved in these works, these noise levels are consistent with those anticipated by the Construction Noise standard NZS6803, and are considered reasonable in the context of their limited duration for daytime activities.

At all times during construction, we recommend that consideration be made of timing and coordination of operations to ensure that the limits stated above will be complied with and noise effects are minimised. We recommend that a Construction Noise Management Plan be prepared and implemented prior to the commencement of any works (other than site investigations). This should be generally in accordance with Section 8 and related annexes of New Zealand Standard NZS6803:1999 Acoustics – Construction Noise which detail the types of construction and procedures that will be carried out to ensure compliance with the Standard and to control noise effects.


7.0 OPERATIONAL NOISE —WIND TURBINE NOISE

Operation noise consists primarily of sound from Wind Turbines. Other noise sources including substations, overhead power lines and traffic noise are discussed in Section 7.6.

The noise levels from these items have been predicted and assessed using the methodologies presented in Section 5.0. Details of these predictions and assessments are discussed in this section.

7.1 Model Inputs—Sound Power Curve

The sound level emitted from a wind turbine varies with wind speed, which can be characterized by a “sound power curve”. Typical sound power curves are shown in Figure 9, which includes sound power level curves for a variety of wind turbines with power ratings between 1.8 MW and 3.0 MW.

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110

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0 5 10 15 20 25

Soun

d Po

wer

Lev

el [d

BA]

Wind speed at hub height [m/s]

Vestas V90 (old design)

Vestas V90 (new design)

Figure 9 – Sound Power Level Curve Comparison

When reported as a single-number value, turbine noise is modelled on the basis of the wind speed at which the peak in sound power level occurs. The range of peak sound power level for the turbines illustrated above is approximately 104 dBA – 109 dBA.

The turbines illustrated above include the Vestas V90 design, in both its older design (109 dBA) and its newer design which has a lower sound power level of 107 dBA. Not included in this graph are as yet un-built turbines which may be available


when the project is built, particularly large turbines which could satisfy the 110 metre rotor diameter design considered in this application.

After a review of available turbine models, Genesis Energy has determined that maximum sound power levels of 110 dBA and 108 dBA for the Large Turbines and Medium Turbines respectively would allow an appropriate degree of flexibility in turbine selection and layout.

For the purposes of modeling and effects assessment it is also necessary to determine the shape of the sound power curve. We have chosen to use the shape of the older Vestas V90 sound power curve as a modelling example because it forms a conservative maximum relative to other typical turbines, including some margin for higher sound power levels from larger turbines built in the near future.

The V90 turbine also exhibits a peak in sound power level at relatively low wind speeds. Using this curve shape in noise assessments ensures that the predicted noise levels are compared against the more sensitive part of the noise limit.

The sound power curves for the modelled turbines are shown in Figure 10. The two curves shown in this figure have been adjusted to produce the nominal sound power level for each Indicative Turbine Layout (108 dBA for Medium Turbines, and 110 dBA for Large Turbines).

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dBA

Sou

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Lev

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Wind Speed (m/s) at hub height

Large Turbines

Medium Turbines

Figure 10—Modelled Sound Power Level Curves


7.2 Model Inputs—Frequency Spectrum

For modeling purposes it is also necessary to determine an appropriate frequency spectrum shape. The shape of the frequency spectrum used in the modelling is taken from the 109.4 dBA Vestas V90 turbine described in the preceding section, and adjusted upwards to represent the Large Turbines or downwards to represent the Medium Turbines.

The frequency spectra used for the 110 dBA Large Turbine and the 108 dBA Medium Turbine are as follows. The octave band values are decibels sound power level, with no frequency weighting (e.g. A-weighting) applied.

Table 13—Modelled Turbine Sound Power Level Spectra

Octave Band Frequency (Hz) A 31.5 63 125 250 500 1000 2000 4000

Large Turbine 110 124.1 120.5 114.3 111.4 107.7 104.3 99.7 85.6

Medium Turbine 108 122.1 118.5 112.3 109.4 105.7 102.3 97.7 83.6

7.3 Model Inputs—Source Location

Each turbine has been modelled as a point source at the height of the nacelle (90 or 100 metres AGL for Medium or Large turbines respectively). This appropriately represents that observation that the noise generated by a WTG is mainly emitted from the tip of each blade, which reaches its maximum output as it passes downward through horizontal (at approximately the height of the hub), and to a nearly negligible extent from the nacelle (which houses the rotating machinery) and the body of the tower itself, which can radiate mechanical noise from the generator housing if not properly isolated.

The 90 and 100 metre nacelle heights are selected as part of the worst-case envelope. Should lower nacelle heights be selected, the sound levels predicted would be expected to decrease by a small amount due to increased screening from terrain, or remain the same.


7.4 Model Outputs

Predicted noise levels for dwellings and schools external to CHWF which are predicted to receive more than 35 dB LAeq from at least one of the Indicative Turbine Layouts are listed in Table 14 below. A map showing these locations is shown in Figure 11.

Predicted noise levels are expressed as Leq decibels Sound Pressure Level, and do not include contribution from noise sources other than the wind turbines. Noise levels relate to the peak sound output, which typically occurs at a wind speed of 10 - 12 m/s at hub height. The sound level at other wind speeds will be less. This is illustrated in detail for relevant locations in Section 7.5 of this report.

Table 14—Predicted Turbine Noise Levels

Indicative Turbine Layout Site Owner 80M 90M 100L 110L Max

X170 Braddick 34 34 36 35 36 X171 Edmonds 35 34 37 36 37 X185 DSM Land Limited 34 35 36 35 36 X187 Rec Rsv NZGZ 1987 p 24 34 34 36 35 36 X188 School NZGZ 1919 p 1490 35 34 36 35 36 X189 School NZGZ 1919 p 1490 35 34 36 35 36 X190 Billington 34 33 35 34 35 X258 Ellmers 32 32 33 33 33 X265 Liverton 39 38 40 40 40 X321 Dalziel 33 33 35 32 35 X358 Musgrove 35 34 35 35 35 X362 Keane 35 33 35 35 35 X377 Wingate 38 37 39 37 39 X378 Goodwin 33 33 35 33 35 X379 Percy 35 34 36 35 36 X380 Wellbrock 34 34 35 34 35 X391 Wellbrock 34 34 36 34 36 X392 Blyth 35 34 36 35 36 X396 Liverton 38 38 40 39 40 X397 Whareroa Pine Hills Ltd 39 39 42 39 42 X403 Richardson 38 37 39 36 39 X405 Kyle 35 34 35 35 35 X407 Liverton 38 38 40 40 40 X408 Inverell Farms Eketahuna 34 36 37 37 37

The predicted noise levels are illustrated graphically as noise contours in Appendix B: Noise Prediction Maps.

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409408

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256258

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171170

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Figure 11: Dwellings

Legend

CHWF Site" CHWF Landowner Dwellings" External Dwellings

Turbine Corridor2km from Turbine Corridor5km from Turbine CorridorIndicative Internal Roads

0 3 6 91.5km


7.5 Assessment of Turbine Noise Effects

The noise sensitive locations listed in Table 14 have been assessed by comparing the predicted noise levels with background noise measurements taken at the dwellings, or at nearby representative dwellings.

These assessments are presented in the following section. For each set of noise measurements presented, the following information is provided:

� The location of the measurement position, and the relative positions of noise sensitive locations at which proposed turbine sound is compared against this measurement;

� A graph describing the relationship between noise level and wind speed. This consists of a set of 10-minute measurement points plotting noise level against wind speed, and a regression line through these points;

� A description of the noise environment and the contributing noise sources;

� A comment on whether time of day or wind speed changed the wind/noise relationship, and if so, a second graph depicting the quietest (most noise sensitive) situation;

� A graph comparing the predicted wind farm noise curve (based on the “downwind-all-directions” worst case) against the background sound curve and the limit derived from the background sound curve.

� The above graph also demonstrates the predicted level for the prevailing wind (315o) and the predicted level for the best-case wind direction for the particular site, to give an indication of the range of sound levels over various wind directions (but in all cases predicted for the loudest wind speed).

It should be noted that in some cases the regression line describing background sound level trends downward at higher wind speeds or upwards at low wind speeds. This is due to the sparse data at these extremities, and does not imply that the noise level behaves in a nonsensical way, nor that the noise limit should become more stringent at higher wind speeds.

The compliance assessment will focus on wind speeds generally below 14 metres per second. However the trend lines are shown with the intent that this limitation is kept in mind.

A summary of the assessments which follow is given in Table 15.


Table 15-Wind Farm Noise Assessment Summary

Site

Maximum Sound Level

(dB LAeq) Maximum Elevation

over Background (dB) Frequency of Elevation

over Background X170 36 11 Rarely X171 37 12 Rarely X185 36 - Rarely X187 36 6 Rarely X188 36 - Rarely X189 36 - Rarely X190 35 5 Rarely X258 33 3 Rarely X265 40 10 Often X321 35 2 Rarely X358 35 4 Often X362 35 4 Often X377 39 8 Often X378 35 4 Rarely X379 36 5 Rarely X380 35 5 Rarely X391 36 5 Rarely X392 36 5 Rarely X396 40 10 Often X397 42 5 Rarely X403 39 2 Rarely X405 35 4 Often X407 40 10 Often X408 37 1 Rarely


7.5.1 Dwellings X170, X171

Noise measurements were made at X171 during December 2010. These measurements have been used to assess the effects of wind farm noise on that dwelling and X170 as shown in Figure 12.

Figure 12 – Noise Assessments near X171

The existing background noise level is dominated by wind noise in local and distant trees at elevated wind speeds, and during daytime hours may include noise from family and farming activities at this dwelling, and road farming activities at adjacent dwellings.

The residential area is surrounded by a small stream, and our noise measurements were taken at a location well shielded from this stream. At other locations within the notional boundary the noise from this stream will likely be higher than shown in these measurements.


Figure 13 shows the relationship between outdoor background noise levels at X171 and wind speeds measured at the nearest meteorological mast at the wind farm site.

y = -0.00027092x4 + 0.01361267x3 - 0.17056309x2 + 1.16041859x + 24.05025232R² = 0.39526566

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Figure 13

Lower noise levels were observed when night-time measurements under northwest wind conditions were isolated, so this condition has been used to assess noise effects to provide a conservative assessment. This data is shown in Figure 14.

y = -0.00029027x4 + 0.01554966x3 - 0.24314628x2 + 2.64187546x + 10.45881726R² = 0.64061938

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Figure 14


Figure 15 shows the predicted WTG noise levels in comparison with the NZS6808 noise limit based on the background noise level described above. Figure 16 illustrates the predicted WTG noise levels at X170, in relation to the background sound measured at X171, which are taken as indicative of the levels at X170.

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Wind Farm - Upwind

Figure 15 – X171 Noise Limit

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Figure 16 - X170 Noise Limit


At the wind speed where turbine noise output peaks, and using the loudest of the Indicative Turbine Layouts, the wind farm sound level is predicted to be 37 dB LAeq at Dwelling X171 and 36 dB LAeq at Dwelling X170.

It is predicted that turbine noise emissions will comply with the noise limit at these dwellings.

Effects Assessment, Dwellings X170, X171

The potential adverse effects of noise from a wind farm are sleep disturbance and loss of amenity.

In assessing the noise effects of the wind farm at these particular dwellings, we note the following:

� While the wind is blowing in the prevailing direction, the sound of the wind farm will be immersed in the existing background sound level for all wind speeds.

� When X170 and X171 are downwind of the wind farm but wind speeds are low or high, the sound of the wind farm will be immersed in the existing background sound level.

� On the rare occasions when X170 and X171 are downwind of the wind farm under moderate wind conditions (7 – 13 m/s), the wind farm noise level will be up to 10 dB higher than the existing background sound level.

While on these rare occasions this sound level is higher than the existing background sound level, this level is regarded as reasonable for the following reasons:

� It occurs infrequently.

� The highest predicted sound level (36 – 37 dBA) is less than the minimum night-time noise limit of 40 dB LAeq most recently recommended by the WHO (World Health Organization, 2009).

� At other times the noise level will be significantly below 37 dB LAeq.

� The highest predicted level is less than the 45 dB LA10 level which would be considered reasonable if assessing night-time noise from another activity such as a hydroelectric generating plant or milk drying plant in this area.

While noise from the wind farm may be audible outside dwellings at times, the noise level is sufficiently low to avoid sleep disturbance and will not result in adverse amenity effects, we thus conclude that noise effects are no more than minor.


7.5.2 Dwelling X185, X408

Noise measurements were made at External Dwelling X185, Waitawhiti Road, during June - July 2011. These measurements have been used to assess the effects of wind farm noise on this dwelling and X408 as shown in Figure 17.

Figure 17– Noise Assessments near X185

The existing background noise level at higher wind speeds is dominated by wind noise in local and distant trees. Little farm activity noise was observed in the noise environment.


Figure 18 shows the relationship between outdoor background noise levels at X185 and wind speeds measured at the nearest meteorological mast at the Site.

y = 0.00011118x4 - 0.00309689x3 - 0.07702823x2 + 3.70925894x + 10.00767257R² = 0.74536235

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Figure 18

Lower noise levels were observed when night-time measurements were isolated, so this condition has been used to assess noise effects. No significant change in noise level was observed between different wind directions. This data is illustrated in Figure 19.

y = -0.00028403x4 + 0.02571275x3 - 0.81714541x2 + 11.57072660x - 18.63415390R² = 0.71088552

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Figure 19


Figure 20 shows the predicted WTG noise levels in comparison with the NZS6808 noise limit based on the background noise level described above.

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Figure 20

At the wind speed where turbine noise output peaks, and using the loudest of the Indicative Turbine Layouts, the wind farm sound level is predicted to be 36 dB LAeq at Dwelling X185.


Figure 21 shows the relationship between predicted WTG noise levels at site X408, and background noise levels and applicable noise limits measured at X185.

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Figure 21


It is predicted that turbine noise emissions will comply with the noise limit at these dwellings.

Effects Assessment, Dwelling X185 and X408


In assessing the noise effects of the wind farm at this particular dwelling, we note the following:

� While the wind is blowing in the prevailing direction, these dwellings will lie downwind from the wind farm.

� At all wind speeds, the sound of the wind farm will be immersed in the existing background sound level.

While on these occasions this sound level is higher than the existing background sound level, this level is regarded as reasonable for the following reasons:


� The highest predicted sound level (36 - 37 dBA) is less than the minimum night-time noise limit of 40 dB LAeq most recently recommended by the WHO (World Health Organization, 2009).





7.5.3 Properties X187, X188, X189, X190

Noise measurements were made at X190 during December 2010. These measurements have been used to assess the effects of wind farm noise on that dwelling and at X187, X188 and X189 as shown in Figure 22.


The existing background noise level is dominated by wind noise in local and distant trees, and by birds. Farm activity noise could not be heard during our visits but may be present at other times. During some times of the day school children can be heard at this dwelling, from the nearby school.



y = -0.00015805x4 + 0.00833760x3 - 0.11998109x2 + 1.51515852x + 23.84414179R² = 0.21333823

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Figure 23

Noise levels were significantly quieter at night than during the day, and the night-time sound levels were lower during north-westerly winds. For the purposes of the residential (X190) and reserve (X187) assessments, the night-time NW wind conditions was used as illustrated in Figure 24.

y = 0.00014483x4 - 0.00774661x3 + 0.12018827x2 + 1.25698005x + 11.45286822R² = 0.51267851

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Figure 24


For the assessment of properties X188 and X189 which are associated with the School (which is only noise-sensitive during the daytime), the daytime data in all wind directions were used, as illustrated in Figure 25.

y = 0.00006175x4 - 0.00264199x3 + 0.04767530x2 + 0.18537123x + 34.31612374R² = 0.27224303

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Figure 25



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Figure 26


It is predicted that turbine noise emissions will comply with the noise limit at this dwelling.


Figure 27 shows the relationship between measured outdoor background noise levels, the applicable NZS6808 noise limits and predicted WTG noise levels at site X187.

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Figure 27


It is predicted that turbine noise emissions will comply with the noise limit at this location.


Figure 28 shows the relationship between measured outdoor background noise levels, the applicable NZS6808 noise limits and predicted WTG noise levels at site X190 relative to daytime background noise levels. This assessment is relevant for the school property at X188 and X189, and in particular we note that daytime noise levels form the appropriate basis for assessment, as this property is only noise sensitive during school hours.

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Figure 28

At the wind speed where turbine noise output peaks, and using the loudest of the Indicative Turbine Layouts, the wind farm sound level is predicted to be 36 dB LAeq at Site X188 and X189.


Effects Assessment, Properties X187, X188, X189, X190


In assessing the noise effects of the wind farm at these particular properties, we note the following:



� When X187 and X190 are downwind of the wind farm but wind speeds are low or high, the sound of the wind farm will be immersed in the existing background sound level.

� On the rare occasions when X187 and X190 are downwind of the wind farm under moderate wind conditions (5 – 13 m/s), the wind farm noise level will be up to 6 dB higher than the existing background sound level.

� Even under downwind conditions, X188 and X189 would not experience wind farm sound levels above daytime background levels which are relevant for the School property.

While on these rare occasions the sound level at X187 and X190 is somewhat higher than the existing background sound level, this level is regarded as reasonable for the following reasons:







7.5.4 Dwelling X258

Noise measurements were made at X258 during October – November 2010. These measurements have been used to assess the effects of wind farm noise on that dwelling as shown in Figure 29.

Figure 29 – Noise Assessment at X258

The existing background noise level is dominated by wind noise in local and distant trees, and by birds. Farm activity noise could not be heard during our visits but may be present at other times.



y = -0.00011563x4 - 0.00462675x3 + 0.18005502x2 - 0.36200991x + 24.64113798R² = 0.13872789

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Figure 30

This data was significantly quieter at night than during the day, however there was no significant difference between sound levels in different wind directions.

For the purposes of this assessment, the night-time noise levels under all wind conditions were used as illustrated in Figure 31. While there is considerable scatter of values across wind speeds, varying the definition of the “night-time” did not yield any better separation of values, and we conclude that this scatter is a characteristic of this site.


y = 0.00086654x4 - 0.05312833x3 + 0.95356954x2 - 4.48675504x + 24.26391332R² = 0.17828954

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Figure 31


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Figure 32




Effects Assessment, Dwelling X258




� When X258 is downwind of the wind farm but wind speeds are low or high, the sound of the wind farm will be immersed in the existing background sound level.

� On the rare occasions when X258 is downwind of the wind farm under moderate wind conditions (7 – 11 m/s), the wind farm noise level will be up to 3 dB higher than the existing background sound level.

While on these rare occasions this sound level is slightly higher than the existing background sound level, this level is regarded as reasonable for the following reasons:


� The highest predicted sound level (33 dBA) is less than the minimum night-time noise limit of 40 dB LAeq most recently recommended by the WHO (World Health Organization, 2009).





7.5.5 Dwelling X265, X396, X407

Noise measurements were made at X265 during October - November 2010. These measurements have been used to assess the effects of wind farm noise at that dwelling and at X396 and X407 as shown in Figure 33.


The existing background noise level is dominated by wind noise in local and distant trees at elevated wind speeds, and during daytime hours is influenced by farming activities operations at this dwelling and adjacent dwellings.



y = 0.00200053x4 - 0.10460626x3 + 1.81641960x2 - 10.84739601x + 45.70208836R² = 0.25282691

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Figure 34

Lower noise levels were observed when night-time measurements were isolated, so this condition has been used to assess noise effects to provide a conservative assessment. This data is illustrated in Figure 35.

y = 0.00124319x4 - 0.08337108x3 + 1.64631868x2 - 10.22779463x + 39.51565215R² = 0.29604840

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Figure 36 shows the relationship between measured outdoor background noise levels, the applicable NZS6808 noise limits and predicted WTG noise levels at site X265.

Note that the background sound curve is not shown at low or high wind speeds, where sparse data resulted in unrealistic curve fits. This results in a more appropriate limit line.

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Figure 36


This noise level just complies with the 40 dBA limit, and the 80M and 90M Indicative Turbine Layouts are 1 and 2 dB quieter respectively. At this site it will be necessary to carefully consider the micro-siting and selection of turbines to ensure compliance with the noise standard.


Figure 37 shows the relationship between measured outdoor background noise levels, the applicable NZS6808 noise limits and predicted WTG noise levels at sites X396 and X407.

Note that the background sound curve is not shown at low or high wind speeds, where sparse data resulted in unrealistic curve fits. This results in a more appropriate limit line.

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Figure 37

At the wind speed where turbine noise output peaks, and using the loudest of the Indicative Turbine Layouts, the wind farm sound level is predicted to be 40 dB LAeq at Dwellings X396 and X407.

This noise level just complies with the 40 dBA limit, and the other Indicative Turbine Layouts are 1 – 2 dB quieter. At this site it will be necessary to carefully consider the micro-siting and selection of turbines to ensure compliance with the noise standard.


Effects Assessment, Dwelling X265, X396, X407




� When wind speeds are low or high, the sound of the wind farm will be near that of the existing background sound level.

� Under moderate wind conditions (4 – 13 m/s), the wind farm noise level will be up to 10 dB higher than the existing background sound level.


� The highest predicted sound level (40 dBA) meets the minimum night-time noise limit of 40 dB LAeq most recently recommended by the WHO (World Health Organization, 2009).





7.5.6 Dwelling X321

Noise measurements were made at 1024 Manawa Road during June 2010. These measurements have been used to assess the effects of wind farm noise on dwelling X321 as shown in Figure 38.

Figure 38 – Noise Assessments near 1024 Manawa Road

The existing background noise level at higher wind speeds is dominated by wind noise in local and distant trees, and by a nearby water course at low wind speeds during the observed winter month. During the day, farm activity noise including stock and dogs, and birds contributed somewhat to the noise environment.


Figure 39 shows the relationship between outdoor background noise levels at 1024 Manawa Rd and wind speeds measured at the nearest meteorological mast at the wind farm site.

y = -0.00043146x4 + 0.01683479x3 - 0.15375700x2 + 0.74614321x + 30.01087601R² = 0.43841157

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Figure 39

Lower noise levels were observed when night-time NW winds were isolated, so this condition has been used to assess noise effects, to provide a conservative assessment. This data is illustrated in Figure 40.

y = -0.00072816x4 + 0.02663429x3 - 0.22507508x2 + 0.72800974x + 28.29451358R² = 0.86533098

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Figure 40


Because these noise levels at elevated wind speeds are dominated by wind in distant vegetation, it is taken to be representative of the noise environment of the nearby noise sensitive location X321.


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Figure 41






� Under all conditions, the sound of the wind farm will be immersed in the existing background sound level for all wind speeds.


� On the rare occasions when X321 is downwind of the wind farm under moderate wind conditions (7 – 11 m/s), the wind farm noise level will be similar to the existing background sound level.

While on these rare occasions this sound level approaches the background sound level, this level is regarded as reasonable for the following reasons:







7.5.7 Dwelling X358, X362, X405

Noise measurements were made at 153 Wairiri Road during June 2010. These measurements have been used to assess the effects of wind farm noise on dwellings X358, X362 and X405 as shown in Figure 42.

Figure 42 – Noise Assessments near 153 Wairiri Road

The existing background noise level is dominated by wind noise in local and distant trees, and possibly a very low level contribution from distant water courses during the observed winter month. During the day, farm activity noise including stock and dogs, and birds contributed somewhat to the noise environment.

Figure 43 shows the relationship between measured outdoor background noise levels at 153 Wairiri Rd, and wind speeds measured at the nearest meteorological mast at the wind farm site. No significant separation of data was found between wind directions or day/night periods.


y = 0.00037399x4 - 0.01994083x3 + 0.36383654x2 - 1.54656237x + 26.97650190R² = 0.31759783

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Figure 43 — 153 Wairiri Road Noise Levels

Because these noise levels are dominated by wind in distant vegetation, it is taken to be representative of the noise environment of the nearby noise sensitive locations X358, X362 and X405.



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Figure 44




Figure 45 shows the relationship between outdoor background noise levels, the applicable NZS6808 noise limits and predicted WTG noise levels at site X362.

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Figure 45





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Figure 46



Effects Assessment, Dwelling X358, X362, X405




� When wind speeds are low or high, the sound of the wind farm will be immersed in the existing background sound level.



While on these occasions this sound level is somewhat higher than the existing background sound level, this level is regarded as reasonable for the following reasons:






7.5.8 Dwelling X377

Noise measurements were made at X377 during August 2010. These measurements have been used to assess the effects of wind farm noise at that dwelling as shown in Figure 47.

Figure 47 – Noise Assessment at X377

The existing background noise level is dominated by wind noise in local and distant trees at elevated wind speeds, and during daytime hours may include noise from farming activities at this dwelling. We understand that logging operations in adjacent forestry land occurred during these measurements, and that this activity commences early in the morning during the nominal night-time period.



y = 0.00055434x4 - 0.02894140x3 + 0.50300188x2 - 1.83272995x + 24.84146632R² = 0.66007859

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Figure 48

Lower noise levels were observed when night-time measurements under northwest wind conditions were isolated, so this condition has been used to assess noise effects to provide a conservative assessment. This data is shown in Figure 49.

y = -0.00170946x4 + 0.05489688x3 - 0.53266034x2 + 2.94168925x + 17.06925869R² = 0.60040629

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Figure 49



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Figure 50






� While the wind is blowing in the prevailing direction, X377 will lie downwind from the wind farm.

� When wind speeds are low or high, the sound of the wind farm will be immersed in the existing background sound level.



7.5.9 Dwellings X378, X379, X380, X391, X392

Noise measurements were made at X379 during October – November 2010. These measurements have been used to assess the effects of wind farm noise on that dwelling and X278, X380, X391, and X392 as shown in Figure 51.


The existing background noise level is dominated by wind noise in local and distant trees. Farm activity noise could not be heard during our visits but may be present at other times. We note that the measurements contain what appear to be steady noise source which occurs at 20 dBA. The logger used for this measurement has a measured noise floor of 19.2 dBA, and this has already been subtracted from this data.



y = -0.00220374x4 + 0.06007709x3 - 0.42222790x2 + 1.50061093x + 25.11101484R² = 0.23255277

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Figure 52

There was a significant separation between noise levels measured during daytime and those from night-time, however there was no significant difference due to wind directions. For the purposes of this assessment, data from all wind directions at night were used, as illustrated in Figure 53.

y = -0.00154925x4 + 0.03495005x3 - 0.00945913x2 - 1.33839663x + 26.93757486R² = 0.28308629

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Figure 53



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Figure 54





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Figure 55





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Figure 56





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Figure 57





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Figure 58



Effects Assessment, Dwellings X378, X379, X380, X391, X392




� When these dwellings are downwind of the wind farm but wind speeds are low or high, the sound of the wind farm will be immersed in the existing background sound level.


� On the rare occasions when these dwellings are downwind of the wind farm under moderate wind conditions (6 – 11 m/s), the wind farm noise level will be up to 5 dB higher than the existing background sound level.

While on these rare occasions this sound level is somewhat higher than the existing background sound level, this level is regarded as reasonable for the following reasons:







7.5.10 Dwelling X397

Noise measurements were made at External Dwelling X397 during June - July 2011. These measurements have been used to assess the effects of wind farm noise on this dwelling.

The existing background noise level at higher wind speeds is dominated by wind noise in local and distant trees, and by occasional household activity and traffic on Rimu Road.


y = 0.00022973x4 - 0.01322014x3 + 0.20813030x2 + 0.86459842x + 18.20248885R² = 0.78507141

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Figure 59

While clustering does not appear to be significant either due to daytime activity or wind direction, the night-time data points are slightly quieter and are used in the subsequent assessment. This data is shown in Figure 60.


y = 0.00007387x4 - 0.00248558x3 - 0.05181766x2 + 3.51752653x + 8.15726942R² = 0.80419588

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Figure 61

The predicted sound level of the loudest of the four Indicative Turbine Layouts is 42 dB LAeq, as shown in Figure 61. The predicted turbine level complies with the


noise limit on the basis of the elevated background noise level at this site. However it is recommended that consideration be given to achieving a noise level of 40 dBA at this site, by selection of wind turbines and final location of these turbines, or that measurements be made over a variety of seasonal conditions to ensure that this elevated noise level represents the long-term environment.

Effects Assessment, Dwellings X397




� When this dwelling is downwind of the wind farm but wind speeds are low or high, the sound of the wind farm will be immersed in the existing background sound level.


While on these rare occasions this sound level is higher than the existing background sound level, this level is regarded as reasonable for the following reasons:


� While the highest predicted level will slightly exceed the minimum night-time noise limit of 40 dB LAeq most recently recommended by the WHO (World Health Organization, 2009), this limit is already exceeded by wind noise in the existing environment.





7.5.11 Dwelling X403

Noise measurements were made at External Dwelling X403 during June - July 2011. These measurements have been used to assess the effects of wind farm noise on this dwelling.

The existing background noise level at higher wind speeds is dominated by wind noise in local and distant trees, and by occasional household activity and traffic on Waitawhiti Road.


y = 0.00002140x4 - 0.00337529x3 + 0.14379857x2 - 1.35629362x + 38.75319335R² = 0.76758570

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Figure 62

While clustering does not appear to be significant either due to daytime activity or wind direction, the night-time data points are slightly quieter and are used in the subsequent assessment. This data is shown in Figure 63.


y = 0.00011386x4 - 0.00965954x3 + 0.28661029x2 - 2.54360629x + 41.14740372R² = 0.81338413

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Figure 63


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Figure 64




Effects Assessment, Dwellings X403




� When these dwellings are downwind of the wind farm but wind speeds are low or high, the sound of the wind farm will be immersed in the existing background sound level.


While on these rare occasions this sound level is slightly higher than the existing background sound level, this level is regarded as reasonable for the following reasons:







7.6 Infrasound and Vibration

Questions about infrasound and vibration sometimes arise in discussions about wind farms. The internet and popular press have contributed to speculations that health effects can occur near wind farms even when audible noise is well controlled.

The literature concerning these areas has been reviewed in detail by the Standards New Zealand NZS6808 revision committee, to the conclusion that neither infrasound nor vibration from wind farms can give rise to health effects, and that no additional steps are required in a noise assessment to ensure that health and amenity are protected.

This section provides some information about these topics to assist with these discussions.

7.6.1 Infrasound and Low Frequency Sound

Infrasound, which is sometimes confused with vibration, is transmitted through the air at very low frequencies (below 20 Hz). Low frequency sound lies within the audible frequency band (above 20 Hz) but below a threshold which varies depending on application, but usually around 200 Hz.

There is a limited amount of reputable information available defining the health effects of infrasound, from any source. It has been suggested that vibroacoustic disease is a phenomenon which occurs following long-term (10 years +) exposure to high levels of low frequency noise (80 dB+).

Experiences some 20 years ago in Europe, from fledgling wind turbine technology, suggest there may have been low frequency noise problems due to a variety of mechanisms. The development of wind turbine technology is such that reputable suppliers guarantee that the operation of their equipment will not generate subjectively significant levels of low frequency noise. The same wind turbine manufacturers have also carried out extensive research into whether or not their equipment does in fact generate infrasound, and if so, to what degree. The research to date has concluded that modern well engineered WTGs do not generate infrasound in sufficient quantities to be of concern to health or amenity.

It is worth noting that infrasound is naturally occurring, and is produced continually by wind interaction with topography, and intermittently from other natural sources.

7.6.2 Vibration

A paper by Peter Styles (Styles, 2005) reviewed a number of studies which demonstrated that vibrations from wind turbines can be transmitted through the ground and detected by extremely sensitive equipment at distances of several kilometers from a wind farm. However the levels of vibration that were detected


are extremely low, in fact several orders of magnitude less than the threshold of human sensitivity.

The context of the Styles study was to determine whether vibration from wind farms would interfere with seismic equipment designed to detect weapons detonation from a distance of thousands of kilometers. This equipment was purposefully located in an area with very low ambient vibration levels. In most populated areas this detection equipment would be infeasible due to traffic activity and other vibration sources.

There is no evidence that WTGs cause ground vibration of significant amplitude to be humanly detectible.

Secondary vibration can occur, in which high levels of audible sound cause components of a dwelling to vibrate. For this to occur, the audible sound levels would need to be significantly higher than those allowed by NZS6808.


8.0 OPERATIONAL NOISE—OTHER SOURCES

Other operational noise sources include substations, on-site overhead power lines, and on-site road traffic. In this section the noise predictions and assessments of these sources are presented.

8.1 Substation Noise Level Predictions

The proposed wind farm design includes a Main Substation (with up to six transformers) and a Satellite Substation (with up to three transformers). For the main substation, two possible locations have been identified. For the Satellite Substation one site has been identified. These locations and their nearest residential neighbours are shown in Figure 65 and Figure 66.

The optional Switching Station may involve one small transformer and lies approximately 2300 metres from the nearest dwelling. The sound power level has not yet been specified, but will be considerably less than that of the substations. The noise level from the Switching Station at dwellings will be less than that from substations.

8.1.1 Model Inputs

The given sound power level of each of the proposed transformers is 94.5 dBA. This includes transformer noise and any associated fans.

The sound power spectrum used for modelling has been taken from the Transpower NZ Ltd North Island Grid Upgrade Project report, Section 13: Substation noise. This report is available at www.gridnz.co.nz, and describes a standard sound power level spectrum for large (above 200 KVA) 33/220 kV transformers, and has been used by Transpower for substation noise predictions.

These spectra were accepted in the proceedings of the 400 kV upgrade hearing, and are consistent with spectra and levels we have observed when investigating modern substation transformers.

Taken together, the sound power level spectrum used for the modelling is as follows:

Table 16–Transformer Sound Power Level

Octave Band Frequency (Hz) 63 125 250 500 1000 2000 4000

Sound Power Level (dB) 92.5 103.5 100.5 91.5 82.5 73.5 65.5


8.1.2 Model Outputs

The predicted sound pressure levels at the nearest external residential dwellings to each substation are given in Table 17 and Table 18.

Figure 65 – Main Substation Locations

Table 17– Sound levels at dwellings near Main Substations

Predicted Sound Pressure Level (dB LAeq)

Dwelling Option 1 Option 2

X359 9 -

X360 9 -

X361 5 -

X377 - 17


Figure 66 – Satellite Substation Location

Table 18 – Sound levels at dwellings near Satellite Substation

Property Predicted Sound Pressure Level

(dB LAeq)

X186 7

X187 11

X188 12

X189 12

X190 10

At all external noise sensitive locations the predicted sound level from any of the substation options is less than the District Plan night-time noise limits (including penalty for tonality) by at least 28 dB, and noise effects will be less than minor.


8.2 Overhead Transmission Lines

Noise from overhead lines consists of tones generated by wind in wires (referred to as aeolian noise), and noise from arcing to damp atmosphere, (referred to as corona discharge). Noise from both of these effects is generally low and weather-dependent.

In the case of aeolian noise, the sound level depends on wire geometry, wind speed, and distance from wires.

In the case of corona discharge, the sound level depends on line voltage, wire geometry, insulator type, atmospheric humidity, and distance from line conductors and insulators.

8.2.1 33kV Overhead Lines

The proposed 33kV overhead line route runs near to dwellings in several locations. Approximate distances are as follows:

Table 19—Nearest Dwellings to Feeder Lines

Dwelling Plan Distance (m)

X377 120

X392 60

X378 60

X391 70

X380 40

X185 50

Corona discharge from 33kV lines is generally not significant, and it is anticipated that there will be no noise effects from corona discharge in this case.

Aeolian tones at a distance of 40 metres (as at dwelling X380), for an array of three conductors of 20mm diameter, are approximately 25 dBA for moderate winds of 8 m/s. At higher wind speeds, the sound level increases in a similar manner to wind in other structures such as trees and buildings.

At further distances from the wires the sound level attenuates to lower levels, at a rate of between 3 and 6 decibels per doubling of distance.


At all dwellings the sound level from wind noise in wires is similar to or less than the environmental noise present during windy conditions, and the effects will be less than minor.

8.2.2 Internal Transmission Line

The 220kV Internal Transmission Line corridor is contained within the CHWF Site, and comes no closer than 800 metres to noise sensitive locations (the nearest such location being dwelling X403).

The issues raised in the previous section regarding wind noise apply to the 220kV lines, and in addition corona discharge noise becomes significant with 220kV lines. The typical effects corridor which results from such a line is on the order of 40 - 60 metres wide.

In this application the distances to noise sensitive locations are much greater than this corridor, and thus noise effects from 220kV lines will be negligible.


8.3 Road Traffic Noise—Operational Stage

During the operation of the wind farm some access to the Site will be required for ongoing maintenance and management of the wind farm. We have considered the noise effects from these vehicles on public roads and within the Site.

8.3.1 Road traffic – External Roads

We understand from the Traffic Effects Assessment that up to ten full-time equivalent staff may be employed to undertake routine operational maintenance of the turbines. The traffic assesment states that this additional traffic will constitute a negligible effect on traffic.

Noise effects from traffic only become significant (that is, a noise level increase of 3 decibels) when traffic flows double. A negligible traffic effect will also produce a negligible noise effect from this traffic.

On this basis we conclude that there will be negligible noise effect resulting from operational road traffic on public roads.

8.3.2 Road traffic – Internal Roads

The impact of vehicles travelling along Internal Roads has been assessed by the same method as was used for construction traffic, but substituting traffic flows of 10 light vehicles per day (two movements per hour) for the peak hour construction traffic flow of 83 light vehicles plus between 5 and 24 heavy vehicles.

At the most affected dwelling, X397, the noise level from vehicle movements is predicted to be 46 dB LA10, which easily complies with daytime permitted activity noise limits. Sound levels at all other dwellings would be lower.

In all cases noise from operational road traffic would produce less than minor noise effects.


9.0 RECOMMENDED MITIGATIONS

In consideration of the predicted noise levels and assessment of effects in this report, we recommend the following mitigations of noise effects to be adopted:

9.1 Construction Noise

The construction of wind farm components will readily comply with reasonable construction noise standards. However during construction of External Roads, and in the operation of construction vehicles over External Roads, there is the potential to produce noise levels which approach the limits of acceptability for construction noise.

To ensure that compliance is achieved, and to address noise issues which may arise upon commencement of construction of the wind farm, we recommend the following:

� A Construction Noise Management Plan be prepared by an experienced noise professional, which will describe the manner in which noise effects will be controlled, including mitigation methods, to comply with the construction noise standard except where appropriate forms of mitigation have been provided, and to minimise noise effects on residents and other noise sensitive activities near the wind farm project. This Construction Noise Management Plan shall include a procedure for responding to noise complaints.

9.2 Operational Noise

At all External Dwellings, the sound levels predicted from operational activities from the proposed wind farm can comply with the limits recommended by NZS6808:2010.

To ensure that compliance is achieved, and to address noise issues which may arise upon commencement of operation of the wind farm, we recommend the following:

� Noise emissions, as assessed by NZS6801, NZS6802 and NZS6808, should comply with limits in the District Plans and with those derived by the method in NZS6808:2010 as appropriate.

� The noise assessment presented in this report shall be reviewed prior to construction of the wind farm. This review shall include a re-calculation of wind farm sound output once the wind turbine selection has been finalised and their operating parameters are known, and their locations have been finalised. This investigation shall produce a Final Operational Noise Assessment Report, in which it shall be demonstrated that the noise limits established in the Noise Effects Assessment report will be met.


� The sound character of the selected turbines should be assessed once the first turbines are installed and commissioned, to ensure that special audible characteristics are not present, and to give the manufacturer the opportunity to rectify any such problems before the remainder of the wind farm is constructed.

� An Operational Noise Management Plan shall be produced, which shall include a description of the monitoring regime that will be employed to determine compliance with noise limits (including the location of monitoring points, duration of measurement, and requirements to report results), and procedures for handling noise complaints. This shall be produced by an experienced noise expert, in conjunction with representatives of the territorial authorities responsible for ensuring compliance with conditions of consent.


10.0 CONCLUSIONS

Construction noise within the CHWF Site can comply with the provisions of NZS 6803:1999 Acoustics – Construction Noise as required by the Tararua and Combined Wairarapa District Plans.

Construction noise from upgrades to External Roads will in some cases exceed the noise limits in NZS6803:1999 for brief periods, and mitigation will be required. There are practicable mitigations available to achieve an acceptable outcome.

New Zealand Standard 6808:2010 provides the relevant noise performance standard for wind farms. This establishes a noise limit of 40 dBA L90 or 5 dB above the existing ambient background sound level, whichever is the higher, which provides adequate protection of health and amenity.

NZS6808:2010 is regarded as an appropriate compliance requirement for this project and in terms of assessment of effects, it provides a conservative approach because:

� The noise propagation calculation is based on a worst-case assumption that the assessment point lies downwind of all turbines at the same time;

� The noise assessment is based on the peak level of sound from the wind farm, which only occurs at certain wind speeds and thus only occurs occasionally. This contrasts to other noise sources, such as geothermal or hydroelectric generation facilities, which produce noise continuously.

The prediction method in NZS6808:2010 was also used as a tool for the selection of suitable sites with regard to noise level compliance measurements.

On the basis of the worst-case of the envelope assessment, all External Dwellings comply with the noise limits in NZS6808:2010. At one External Dwelling, compliance is achieved on the basis of existing elevated background noise levels, and it is recommended that consideration be given to final placement and selection of wind turbines such that the fixed limit of 40 dBA be met as closely as practicable, or that the higher noise limit be firmly established.

The wind farm can be designed so that the noise level from wind turbines will be reasonable at all External Dwellings.

Substation noise can comply with noise standards set in the district plan, and noise effects will be less than minor at all External Dwellings.

Noise from overhead transmission lines is predicted to be 25 dBA or less at all External Dwellings, and noise effects will be negligible.


Road traffic noise from Internal Roads during the operational stage will be 46 dB LA10 or less at all External Dwellings, and resulting noise effects will be less than minor.

A set of recommendations has been proposed, including the establishment of a Construction Noise Management Plan and an Operational Noise Management Plan, and the preparation of a Final Noise Assessment Report. These recommendations will ensure that the noise emissions from the project will comply with the relevant noise rules and produce noise effects no greater than described in this report.


APPENDIX A: TYPICAL SOUND LEVELS

The figure below is provided to give a day-to-day context for various sound pressure levels. A comparison can be drawn between the predicted noise levels in the preceding tables and typical noise situations shown in the illustration below , resulting from the given noise sources.


APPENDIX B: NOISE PREDICTION MAPS

The maps on the following four pages illustrate the noise contours of the loudest of the four Indicative Turbine Layouts. At most locations this level results from the 100L Indicative Turbine Layout, but at some locations a particular turbine from another layout drives the contour.

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APPENDIX C: REFERENCES

Styles, P. (2005). A Detailed Study of the Propagation and Modelling of the Effects of Low Frequency Seismic Vibration and Infrasound from Wind Turbines. First International Meeting on Wind Turbine Noise. Berlin. World Health Organization. (2009). Night Noise Guidelines for Europe. Copenhagen: World Health Organization.

castle hill wind farm - gw · standard nzs6803:1999 for construction noise, ... 2.0 glossary of...

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