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Noise Policy
Spring Range LandScape Guardians
Noise Policy
Version 1.0
15th September 2006
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Reproduction for purposes other than those given above requires the prior
written permission of the Spring Range Community Landscape Guardian Association
Inc..
TABLE OF CONTENTS
1 Spring Range Land Guardians - Noise Policy.
1.1 Introduction - The need for agreed standards
3 Standards Applied to Wind Plants
4 Spring Range Amendments to NSW INP Guidelines for Wind Farm Noise.
4.1 Scope of these guideline modifications.
4.2 Noise Criteria for New Developments
4.2.2 Application of the criteria
4.2.3 Modifying Factor Adjustments
4.2.4 Temperature Inversion Strength
4.2.5 Temperature Inversion and Atmospheric Stability.
4.2.6 Changes to Turbine Types and Layouts
4.2.8 Development Approval Conditions
6 Appendix A - A Review of NSW Industrial Noise Policy as applied to wind farms
6.1 NSW Industrial Noise Policy
6.2 Spring Range Assessment of NSW Industrial Noise Policy
7 Appendix B- Review of SA EPA - Environmental Noise Guidelines: Wind Farms
7.1 SA EPA Environmental Noise Guidelines: Wind Farms
7.2 Spring Range Assessment of SA EPA Wind Farm Guidelines
8 Appendix C - Critical Noise Scenario For Spring Range
9.1.3 Background Noise Determination - Threshold Modification
9.1.4 Application of Noise Criteria at Property Boundary
9.1.5 Modifying Factor Adjustments
9.1.6 Consultation and Negotiation
10 Appendix E - Long Term Regulation of Noise Pollution
11 Appendix F - About Spring Range Community Landscape Guardians
1.1 Introduction - The need for agreed standards
Federal Government policies have encouraged rapid growth of wind energy projects in Australia. In 2006 in NSW alone over 20 projects with 1080 turbines were either installed or planned.
At full power a typical 2 megawatt wind turbine has a source noise power level of 103 dB(A). Each project comprises many such turbines distributed across several square kilometres of country.
With few exceptions, turbines are located in tranquil rural areas with low background noise -often 25 dB(A) or less. It is clear that as well as transforming the visual landscape, wind turbines transform the acoustic landscape for many parts of Australia.
Noise pollution from industrial sources increasingly intrudes into the areas where people live and is of concern to governments and international agencies alike (refer : United Nations World Health Organisation- Occupational and Community Noise 4)
Noise pollution is a major obstacle to community acceptance of wind energy. Sensible noise standards embraced by all parties are as essential to the wind industry as they are to the community.
This document examines the flaws in existing standards and outlines principles which may lead to regulation of noise to a level more accepted by the community.
the noise regulation changes suggested here address only the current commercial climate under which NSW wind energy projects are approved AND SHOW HOW SHORT TERM COMPROMISES WITH COMMERCIAL INTERESTs MAY BE REACHED. THEY DO NOT ADDRESS THE LONG TERM ISSUE OF ENVIRONMENT PROTECTION FROM INDUSTRIAL NOISE POLLUTION. For a more complete discussion refer to Appendix-E.
2 NSW Legislation
Noise pollution is defined under the Protection of the Environment Operations Act 1997 (POEO Act) as 'the emission of offensive noise, which means noise that by reason of its level, nature, character or quality, or the time at which it is made, or any other circumstances, is harmful (or is likely to be harmful) to or interferes unreasonably (or is likely to interfere unreasonably) with the comfort or repose of a person outside the premises from which the noise is emitted'. The POEO (Noise Control) Regulation 2000 sets certain limits on noise emissions from motor vehicles, vessels and domestic use of certain equipment.
It is important for anyone resolving disputes over noise pollution to realise that what is music to one person might be offensive noise to another. In responding to noise complaints, an authorised officer will take the approach of what a 'reasonable person' would consider offensive.
3 Standards Applied to Wind Plants
A review of guidelines currently applied to wind energy projects in NSW (refer Appendices A and B) highlights the different approaches to standards development. As a result of that review our Association concludes that the precedent of standards applied to approval of wind energy projects for Spring Range should be:
- NSW Industrial Noise Policy - as amended by this document
- United Nations World Health Organisation - Guidelines for Community Noise
- Other Relevant Standards (Eg. SA EPA Environmental Noise Guidelines - Wind Farms)
Where more than one guideline is specified, and the standards conflict the more stringent requirement should apply.
Although the NSW Industrial Noise Policy is not specifically framed for wind energy projects it contains a base set of noise requirements which readily adapt to wind farms and if amended can provide some protection against noise pollution.
4 Spring Range Amendments to NSW INP Guidelines for Wind Farm Noise.
Spring Range Community Land Guardians Association holds the view that the NSW Industrial Noise Policy provides a good base document for regulating wind turbine noise. That document requires modifications to strengthen its requirements for projects in quiet rural areas and this document sets out modifications we believe are essential. The amendments are designed as realistic criteria to preserve long term commercial interests while safeguarding the community which hosts turbines.
4.1 Scope of these guideline modifications.
These modifications address the quiet rural residential conditions prevailing at Spring Range and cover noise in the audible frequency range. They do not deal with very low frequency noise, infrasound or vibration.
4.2 Noise Criteria for New Developments
Project noise as defined by the NSW Industrial Noise Policy using the LAeq descriptor should be used to describe project noise levels. As defined in that policy intrusiveness and amenity criteria apply and the more stringent of these criteria sets the noise levels for a project.
- Intrusiveness
Source Noise Level (LAeq, 15 minute) < rating background level plus 5
Rating Background Level is as defined by the NSW Industrial Noise Policy with the modifications noted below.
* Amenity
Defined as per table 2.1 in the NSW Industrial Noise Policy with the following modifications
Table 2.1 Modifications
|
|
|
Time of Day
|
Recommended LAeq. Noise Level, dB(A)
|
|
|
|
|
|
Acceptable
|
Recommended Maximum |
|
Residence |
Rural |
Day
|
45
|
50 |
|
Evening
|
40 |
45 |
||
|
Night
|
35
|
35 |
||
4.2.1 Rating Background Level
The rating background level is as defined in the NSW Industrial Noise Policy using the LA90,15 minute descriptor with the deletion of the clause:
"where the rating background level is found to be less than 30 dB(A), then it is set to 30 dB(A)."
ie. The rating background level is to be set at the actual background noise of the locality.
Background noise level is to be determined at a time representative of the quietest season of the year and to include temperature inversion conditions where present.
4.2.2 Application of the criteria
In all cases project noise criteria are to be applied at the most affected boundary of the receiving property.
4.2.3 Modifying Factor Adjustments
Modifying factor adjustments as specified in the NSW Industrial Noise Policy are to be retained and supplemented with an entry to table 4.1 of that policy to more specifically take account of annoyance arising from modulation of turbine noise at blade passing frequency, or beats of that from multiple turbines.
A possible addition to the table is suggested here:
Table 4.1 Addition to Modifying Factor Corrections
|
Factor
|
Assessment/ measurement |
When to apply |
Correction1 |
Comments
|
|
"Swish" Modulation |
A-weighted fast response and modulated response
|
If difference in A-weighted maximum noise levels between fast response and modulated response is greater than 2 dB
|
5 dB |
Characterised by blade passing frequency, or beats of these frequencies. |
To support this entry the following definitions are applied:
Swish
The term "swish" for wind turbines is here used to define the aerodynamic noise predominately generated by turbulence around the trailing edge of wind turbine blades. For constant rotation speed of the turbine and for a distant observer the swish is a relatively constant sound.
Modulation of Swish
The term "modulation of swish" is here used to describe pulsing or modulation of aerodynamic noise which may emanate from a turbine. Modulation of the noise for a single turbine can be caused by the passing of the blade in front of the tower or by differences in flow regimes between the top and lowest point of blade rotation. The frequency of modulation is likely to occur at blade passing frequency, or by beats of those frequencies where multiple turbines are involved.
4.2.4 Temperature Inversion Strength
Winter months in Canberra are on average cold and dry. Average annual rainfall over the three years of a recent drought was 525 mm. The strength of temperature inversions in the region are therefore likely to be closer to those occurring in arid conditions than in more temperate regions. The default temperature inversion for noise assessment should therefore be 80C / 100m (G-class stability category). An alternative strength should be permitted where proponents produce measurements to justify it.
4.2.5 Temperature Inversion and Atmospheric Stability.
Temperature inversions alter the air flow regime in which wind turbines operate and background noise occurs. Airflow models over complex terrain (such as ridgelines) are also modified by atmospheric stability. It is essential when determining wind farm noise levels that these flow regimes be taken into account, particularly when correlating turbine noise with background noise.
Where temperature inversions are shown to be present background noise measurements and compliance testing must be done under representative inversion conditions in a stable atmosphere.
4.2.6 Changes to Turbine Types and Layouts
Substitution of a turbine make and model different to that specified for project approval may be done only where it can be shown the substitution results in lower noise level at all affected receivers for all operating wind speeds.
4.2.7 Complaints System
It is essential that any noise complaints system be focused on fixing the source of the complaint rather than "managing" the complainant. Any complaint system must be run by a body independent of the proponent, which must have the power to fix the complaint or require removal of its source.
4.2.8 Development Approval Conditions
Compliance with the conditions as defined in the NSW Industrial Noise Policy and as amended by the modifications proposed here should be binding on the proponents for wind energy development approvals and wind plant operations.
5 References
1. NSW Industrial Noise Policy, ( http://www.epa.nsw.gov.au/noise/industrial.htm )
2. South Australian Environment Protection Authority - Environmental Noise Guidelines: Windfarms, (http://www.epa.sa.gov.au/pdfs/windfarms.pdf)
3. NSW Protection of the Environment Operations Act 1997 No 156 (http://www.legislation.nsw.gov.au/viewtop/inforce/act+156+1997+first+0+N)
4. United Nations World Health Organisation - Occupational and Community Noise (http://www.who.int/mediacentre/factsheets/fs258/en/)
5. United Nations World Health Organisation - Guidelines for Community Noise (http://www.who.int/docstore/peh/noise/guidelines2.html)
6. Cullerin Range Wind Farm Noise Impact Assessment
(http://www.taurusenergy.com.au/TaurusEnergy-Cullerinproject.html)
7. The Sound of High Winds: the effect of atmospheric stability on wind turbine sound and microphone noise, G. P. Van den Berg, University of Groningen (http://irs.ub.rug.nl/ppn/294294104)
8. Wind Turbine Acoustic Noise - white paper prepared by Renewable Energy Research Laboratory Dept of Mechanical and Industrial Engineering University of Massachusetts at Amherst (http://www.ceere.org/rerl/publications/whitepapers/Wind_Turbine_Acoustic_Noise_Rev2006.pdf)
6 Appendix A - A Review of NSW Industrial Noise Policy as applied to wind farms
6.1 NSW Industrial Noise Policy
This policy provides guidelines for general industrial noise. Its stated aim is:
"to protect at least 90 per cent of the population living in the vicinity of industrial noise sources from the adverse effects of noise for at least 90 per cent of the time."
The policy has limited applicability to wind farms and notes this as follows:
"In particular instances specific noise criteria may be defined for sources where the standard approach is not appropriate, for example, wind farms."
The policy defines two levels of criteria to be applied to noise levels as summarized below and requires that the actual noise level be the more stringent of the two:
- Intrusiveness
Source Noise Level (LAeq, 15 minute) < rating background level plus 5
Where the rating background level is found to be less than 30 dB(A), then it is set to 30 dB(A).
* Amenity
|
Time of Day
|
Recommended LAeq. Noise Level, dB(A)
|
|
|
|
Acceptable
|
Recommended Maximum |
|
Day
|
50
|
55 |
|
Evening
|
45 |
50 |
|
Night
|
40
|
45 |
The policy adds a penalty of up to 5 dB to the noise source where it contains certain characteristics, such as tonality, impulsiveness, intermittency, irregularity or dominant low-frequency content. The policy also requires meteorological effects to be taken into account when assessing noise and specifies default criteria for temperature inversions.
6.2 Spring Range Assessment of NSW Industrial Noise Policy
6.2.1 Strengths
1) The policy aims are clearly stated and reasonable
2) The policy provides definitions for sound levels and background noise and sets good procedures for measuring them.
3) The policy provides for attenuation of 10 dB between exterior and interior of buildings.
4) The policy requires meteorological conditions be taken into account, specifically includes temperature inversion, and provides default values for assessing it.
5) The policy specifies that seasonal variations be filtered out when measuring background noise.
6) The policy requires assumptions made when determining noise levels to be clearly validated and reported in the assessment.
6.2.2 Limitations
1) The policy is designed for single industries located in rural areas often with industrial estates in mind. It does not take account of the extensive nature of wind power complexes where noise is often continuous and turbines are distributed among rural residences across wide areas. The policy itself specifies this limitation:
"In particular instances specific noise criteria may be defined for sources where the standard approach is not appropriate, for example, wind farms."
2) The setting of background noise to a minimum of 30 dB is artificial and unrealistic for quiet rural areas. In such locations the industrial noise can exceed the background by 10 dB or 15 dB and it becomes the dominant noise for that environment.
3) For rural areas the "Amenity" noise levels are set at high levels and reflect a degree of annoyance rather than comfortable amenity. Where assumptions of attenuation at building facades are not realized the recommended maximums will contravene WHO sleep guidelines.
4) There is no provision for measurement to confirm the attenuation at building facades
5) The policy applies at or near residences not at property boundaries. It provides no protection for property owners where noise spills over a boundary and restricts the present or future use an affected owner may plan for his property.
6) Provides for complaint systems to be run by proponents rather than an independent body.
7) The policy focuses on monitoring and management of complaints and exhaustion of mitigation measures rather than removal of the source of the problem. No sanctions are specified where noise levels are not in compliance.
8) The policy provides guidelines only. It is non binding:
"The industrial noise source criteria set down in Section 2 are best regarded as planning tools. They are not mandatory"
7 Appendix B: Review of SA EPA - Environmental Noise Guidelines: Wind Farms
7.1 SA EPA Environmental Noise Guidelines: Wind Farms
This policy was developed for wind turbines and has been cited in approval conditions for NSW wind plants (Eg Cullerin Range). For new developments its noise criteria can be summarised:
The predicted equivalent noise level (LAeq,10), adjusted for tonality should not exceed:
*35 dB(A), or
*the background noise (LA90,10) by more than 5 dB(A)
whichever is the greater, at all relevant receivers for each integer wind speed from cut-in to rated power of the WTG.
The background noise is determined by a specified data collection and regression analysis process. The policy makes provision for correlating noise levels and background noise with wind speed and defines procedures for doing this. It states:
Wind speed 10 m above the ground at the wind farm site and background noise at the relevant receiver must be correlated so that background noise and wind farm noise can be compared.
7.2 Spring Range Assessment of SA EPA Wind Farm Guidelines
7.2.1 Strengths
1) The policy is designed specifically for wind turbines and addresses many of the relevant issues.
2) The policy provides definitions for sound levels and background noise and sets practical procedures for measuring them.
7.2.2 Limitations
1) The policy allows noise levels of 35 dB(A) in quiet areas where background noise may be as low as 20 dBA. In such locations turbine noise can exceed the background by 10 dB or 15 dB and become the dominant noise for that environment.
2) The policy relies on higher background noise accompanying higher turbine noise as wind speeds rise. Research shows the assumption to be not always valid.
3) No maximum limit to noise is stated. Where background levels are high enough the policy permits noise levels in excess of World Health Organisation guidelines.
4) The policy does not explicitly require meteorological effects (such as temperature inversion and wind gradients) to be taken into account.
5) The policy measures noise levels at the receiver, not at property boundaries. Noise which spills across boundaries and exceeds permitted residential levels restricts the future use of properties.
6) The policy allows noise predictions to be made for a turbine type and model other than the one to be installed and implies that changes to turbine positions may be permitted subsequent to the noise assessment.
7) The guidelines do not adequately account for annoying modulation of sound levels which often accompany wind turbines. The guideline refers to aerodynamic "swish" of turbine blades as being acceptable, but fails to adequately distinguish between this and the modulation or "pulsing" characteristic of turbine sound. The annoyance attracts no corrective factor.
8) The guidelines allow background noise measurements to be collected in periods which do not reflect seasonal variations.
9) The policy provides guidelines only. It is non binding.
8 Appendix C - Critical Noise Scenario For Spring Range
The following scenario is considered to provide the most critical noise environment for Spring Range.
It is a clear day in late Autumn or early Winter. During the day there is a moderate wind at ground level providing a moderate background noise level.
On Spring Range one hundred and seventy metres above the plain the wind is accelerated by the ridge and blows strongly on Mt Spring. At hub height, eighty metres above the ridge the wind is strong enough to allow wind turbines if they were present to operate at maximum power. At a distance of one kilometre downwind turbines would be prominently audible, but not necessarily annoying above a moderate background noise level.
At sunset the temperature plummets and a temperature inversion develops. Around the dwellings the wind drops to nothing. In the late evening it is crisp, clear and still. The night promises a heavy frost. Commuters to Yass on the Barton Highway four kilometres away have gone home now and are no longer heard. It is approaching winter so there are no crickets, and the frogs on the dams have long since ceased to call. There is NOTHING to disturb the quiet. A meter recording background noise would bottom out at 20 dB(A) or below.
Meanwhile on the ridge, above the temperature inversion and the quiet conditions around the dwellings on the plain, the wind still blows and at turbine height above the ridge it is still strong enough to allow a turbine to generate near maximum power.
Wind turbine noise under such conditions would be the dominant noise source at annoying noise levels for many square kilometers of a place that people call home.
9 Appendix D - Rationale for Guideline Modification Proposed by Spring Range Community Landscape Guardians
9.1.1 Intrusiveness
For rural areas an acceptable noise level of background + 5 dB provides developers with an opportunity to introduce industry including wind turbines. At this level turbine noise will be clearly audible but adverse effects of extreme annoyance will be prevented.
Our Association prefers the approach of the NSW industrial noise policy which specifies a single rating background level rather than the SA EPA guidelines which plots background noise as a function of wind speed. The reason for selecting the NSW INP approach is that hub height wind speeds and ground level background noise are not strongly correlated in temperature inversion conditions.
It is important that the Rating Background Level closely represents the critical conditions described in the section, Critical Noise Scenario - Spring Range.
Background measurement must be performed and derived in a manner which captures such conditions.
9.1.2 "Amenity" Modifications
The criteria specified in table 2.1 of the NSW Industrial Noise Policy are 15 dB(A) to 20dB(A) above existing levels for quiet rural location and would certainly destroy "amenity" for such districts. In the case of quiet rural areas the criteria are unlikely in most cases to be limiting to development because intrusiveness criteria will apply. However the amenity limits of the policy, as specified, will not prevent noise pollution gradually inserting itself unchecked into a district as background noise creeps higher.
It is therefore appropriate to replace them with limits more consistent with realistic upper bounds for the locality. The modified limits proposed here still represent an extreme of noise unlikely to affect any currently projected development.
The modified night time limit is proposed to ensure a conservative approach to compliance with WHO sleep disturbance criteria ( 30 dB(A) for sleeping quarters). The modified maximum limit of 35 dB(A) is set to allow for variability in rural house construction and a margin of error in building facade attenuation.
9.1.3 Background Noise Determination - Threshold Modification
In very quiet rural conditions background measurement have shown that sound level can drop to at least below 25 dB(A) and in some instances even below 20 dB(A). In such circumstances If a new sound of 35 dB(A) (which is almost constantly present) were then added in such an environment it would dominate the acoustic environment and would certainly constitute a loss of amenity.
To place an artificial lower threshold of 30 dB(A) on background noise levels as proposed by the NSW Industrial Noise Policy in such conditions is artificial and inconsistent with the policy's stated aims: "To protect restore and enhance the quality of environment of NSW and "preserve amenity for specific land uses"
The inconsistency can be removed by dispensing with a lower limit entirely. Let the Rating Background Level serve its intended function as the real background noise of the location.
9.1.4 Application of Noise Criteria at Property Boundary
Rural residential properties at Spring Range vary in size from about 20 acres to 200 acres. The area is on the fringe of Canberra and has long term residential development potential. Many blocks allow options to build a second residence on them.
If a noise source produces limit levels near a dwelling then the limits will be exceeded for all that land between the dwelling and the property boundary. Future use of the affected piece of land for residential purposes is thus compromised.
To avoid this impact, project noise criteria need to be set at critical property boundaries.
9.1.5 Modifying Factor Adjustments
Wind turbine noise is likely to be constantly present for long periods and is no less annoying than any other noise. It should be treated as such. Modulation, tonality or other annoying characteristics need to be assessed.
Modulation at blade frequency and beats of this noise has been shown to be a common source of complaint7. Although it might properly be dealt with under "impulsive noise" in Section 4 of the NSW INP the definitions and regulations should be unambiguous in dealing with it.
9.1.6 Consultation and Negotiation
There have been over forty community groups in Australia set up in the past few years in reaction to wind farm projects. A common theme, high on the concern of every group has been too little consultation, too late between developers and the community2.
The noise criteria proposed here are not restrictive to well sited wind farms. Our Association recommends an approval process which adopts them as the baseline for consultation between affected parties and the proponent, and encourages the consultation process provided for in The NSW Industrial Noise Policy.
An agreed position negotiated between affected parties is in all cases preferable to imposed regulation. We support any alternative noise criteria negotiated within the framework of the NSW Industrial Noise Policy.
_______________________________________________________________________
2 In the case of Spring Range a developer advised shareholders that it was planning a wind energy project in mid 2005. By Septermber 2006 no community consultation had occurred.
10 Appendix E - Long Term Regulation of Noise Pollution
Homo Sapiens has always been able to adapt to extremes of environment, and our ability to shape that environment is greater than ever before.
Australia has some latitude in choosing the environment in which we all live. Do we choose to live in a way where we are most at harmony with our surroundings, or do we shape our environment to our limits of tolerance?
The long term effect of existing noise policy eventually produces an environment set at our level of tolerance rather than at optimum conditions for living. The source of the problem is the growth factor enshrines in the "intrusiveness" criteria of noise policies which allow sounds from new projects to exceed background noise by 5 dB(A).
The cumulative result of many projects is for background noise to become gradually louder as development occurs until the "amenity" limits of the existing noise policies are reached. These limits are set at a level well beyond "amenity". For example the NSW Industrial Noise Policy sets an urban upper limit at 65 dB(A), a level which any animal would find stressful. Is the human animal any different?
If we seek input from the fields of anthropology and human psychology to define an acoustic environment where human performance is at its optimum then we can frame our regulations accordingly. A key part of humanity focused regulation would be zero growth. The sounds from industrial activity must merge into existing background noise levels. No project should be permitted to exceed these without a most compelling reason.
It might be argued that an increase in background noise is "inevitable" with development. However, that is not reason for inaction. Unless society puts in place pressures to resist growth in noise levels we will leave future generations to wonder why we did not do so when we had the opportunity.
11 Appendix F - About Spring Range Community Landscape Guardians
This document was prepared by Spring Range Community Landscape Guardians Association Inc. Although the Association is dedicated to preserving the character of the Spring Range area and is opposed to the installation of wind turbines there, it is not opposed to wind turbines per se. The Association recognizes the need for a consensus approach to addressing greenhouse emissions issues, and a responsible approach to renewable energy projects.