NZS 6808:2010Acoustics –Wind farm noise

Programme

• Introduction• Wind farm acoustics 101• Key changes to NZS 6808• NZ projects and prospects• Example • Questions

Introduction

White Hill

Motorimu

• NZS 6808:1998• SNZ review (Nov 2004)

• NZWEA / EECA Review (May 2007)

• SNZ scoping workshop (Nov 2007)

Timeline

Committee

• Energy Efficiency and Conservation Authority• Executive of Community Boards• Local Government New Zealand• Massey University• Ministry for the Environment• Ministry of Health• New Zealand Acoustical Society• New Zealand Institute of Environmental Health Inc.• New Zealand Wind Energy Association• Resource Management Law Association• University of Auckland

• NZS 6808:1998• SNZ review (Nov 2004)

• NZWEA / EECA Review (May 2007)

• SNZ scoping workshop (Nov 2007)

• Committee (Jul-Dec 2008)

• Consultation (Mar-Apr 2009)

• Committee (May-Oct 2009)

• NZS 6808:2010

Timeline

Process

• Review research and current practice

• Propose method based on the evidence

• Test and debate proposed method

• Reach consensus position

Potential effects

• Infrastructure

• Visual

• Construction phase

• Noise

Wind farm acoustics 101

Sound

Pressure changes

(Pascals)

decibels (dB)

Sound levels

NZS 6808

decibels

• 1 dB + 1 dB = 4 dB• 35 dB + 35 dB = 38 dB

• + 3 dB audible difference

• + 10 dB doubling of subjective loudness

Frequencies

• Human hearing – less sensitive to low frequencies

• A-weighting approximates human hearing

L90

30 dB

40 dB

50 dB

60 dB

70 dB

Time

L90

Sources of sound

• Blade aerodynamic sound• Gearbox, generator, hydraulics mechanical sound• Transformer electrical sound

Key changes to NZS 6808

40 dB

45 dB

25 dB

50 dB

35 dB

Noise limits

High amenity noise limit

30

35

40

45

50

55

20 25 30 35 40 45Background sound level, dB

Noi

se li

mit,

dB

Noise limit

Noise limits

High amenity noise limit

West WindLess than 25 dBLess than 1.5 m/s NZS 6808:2010

6 m/s or less

Cumulative effects

• Noise Limits apply to total sound from:– all wind farms– all stages of a wind farm

0

10

20

30

40

50

60

70

80

90

100

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2

Wind speed relative to 10 m

Heigh

t (m)

Wind speed height

Predictions

Ground attenuationScreening

terrain, foliage, buildingsOctave-bands

DistanceAir absorption

ISO 9613

30 dB

40 dB

50 dB

60 dB

70 dB

Time

L95

L90

Measurements

Special Audible Characteristics

• Tonality

• Impulsiveness

• Amplitude Modulation

Small wind turbines

• Less than 200 m2 swept rotor area– approximately 8 m blade length

• District plan limits

• On/off tests

Alleged health effects

• Literature reviewed

• No causative link shown to exist

• Inaudibility not justified

• Attitude influences perception of noise

Consent conditions

• Recommended conditions in NZS 6808:2010

• Procedural details not required

Wind DirectionsAn update on New Zealand’s wind energy activity

Fraser Clark, Chief ExecutiveRMLA NZS6808 Roadshow, Palmerston North, 29 March 2010

Outline> Wind energy – the technology> Why wind energy> The industry today> Where we’re headed

About NZWEA> Represents over 80 organisations:

> Generators and developers> Transpower and lines companies> Wind turbine manufacturers> Consultancies, financiers and legal firms.

> Policy & regulatory advocacy, public awareness and industry development.

> Utility scale generation only

Main components of a wind turbine

Siemens SWT-2.3-82> West Wind> 2.3 MW rated output> 9,500 MWh/yr

(~1,150 homes)> 40 metre blade length> 67 metre high tower

Tower

Nacelle

Hub

Blades

Foundation (underground)

Main components of a wind turbine

Windflow 500> Te Rere Hau> 0.5 MW rated output> 1,300 MWh/yr

(~160 homes)> 16.2 metre blade length> 30 metre high tower

Tower

Nacelle

Hub

Blades

Foundation (underground)

How it works…

Wind direction

Electricity to grid (via substation)

Not an aeroplane propeller, but it does have wings…

How big?

BrooklynMost new wind farms

Drivers of increasing size include higher yields and reduced infrastructure

Windflow/Te Rere Hau

Selection of size & model depends on specific site characteristics

When is a wind farm a wind farm?> 1 to 100+ turbines> 30 to 100 m high towers> 2 or 3 blades> Arrangement influenced by wind conditions, terrain,

turbine size/spacing

Source: Transpower

1.6m residential consumers (33%)

0.2m commercial consumers (23%)

0.1m industrial consumers (44%)

Electricity:a national system…

… with national significance

Significance is acknowledged in case law

“Electricity is a vital resource for New Zealand. There can be no sustainable management of natural and physical resources without energy, of which electricity is a vital component “

Genesis Power Ltd. And Anor v Franklin District Council (‘Awhitu’), A148/05 at [64]

Why wind energy?> No fuel price

> No fuel risk

> No carbon risk

> Portfolio and location diversity

> Proven technology

> Plenty of energy

Source: Contact Energy HY Results

Source: Contact Energy HY Results

Meridian Energy “Choices, Options,

Decisions 2009 Update”

Competitive with other technologies

Contributing to the economy> Price taker – does not cause electricity price rises

(actually reduces spot prices).> Ongoing regional economic benefits &

employment ($150m+ at construction).> Low-risk, long-term infrastructure

(no fuel price, dependable fuel supply, no carbon emissions).

Contributing to security of supply> West Wind

> Voltage support> Local generation kept the lights on during substation fire

> Energy supply during dry years(i.e. White Hill during 2008).

> Technology improvements mean that wind farms can provide some ancillary services.

Other advantages for NZ> No greenhouse gas emissions> No fuel price or supply risk> World-leading wind resource> Potential sites nation-wide> Scaleable> Hydro base increases flexibility of use> Reduces dry year supply risk> Existing land use retained

Wind Energy now

Planned

Operating and under construction

Up to 630 MWHigh Court

??? MWUnder Investigation

Up to 1,150 MWEnvironment Court/

Board of Inquiry

Up to 1,016 MWConsented

577.8 MWInstalled by end 2011

80.4 MWUnder Construction

497.4 MWInstalled CapacityWaikato

11%

Manawatu 52%

Wellington & Wairarapa 26%

Marlborough & Canterbury 0.2%

Southland & Otago10%

Recent highlights> Project West Wind and 2 small wind farms> 500 MW installed capacity> 4-5% of NZ’s electricity

Future opportunity

38,00040,00042,00044,00046,00048,00050,00052,00054,000

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

Year

GW

h Demand Growth

Dry years,Fuel risk,Retirements

Recession?

How much? How soon? How fast?> Electricity demand growth estimate: 1.5% per year

> 42,245 GWh generated in 2008

> 30% increase needed by 2025 (54,410 GWh)

How much? How soon? How fast?> Electricity demand growth estimate: 1.5% per year

> Reducing supply and price risks> “Dry year” risk

> Fuel supply and price risks

> Introduction of carbon price

How much? How soon? How fast?> Electricity demand growth estimate: 1.5% per year

> Reducing supply and price risks

> 90% renewable electricity by 2025 target> Up from 65% now

> With demand increasing, 70-100% increase in renewable generation

How much? How soon? How fast?

> Electricity demand growth estimate: 1.5% per year

> Reducing supply and price risks

> 90% renewable electricity by 2025 target

Wind energy in 20 years:

> 2,500 to 3,000 MW, up from 500 MW

> 20% of our electricity, up from about 4%

> Variety of small and large-scale projects throughout NZ

In line with international trends

Rapid global wind energy growth is being facilitated by support schemes…

…while in New Zealand projects proceed on a purely economic basis.

World-class performance

Source: NZWEA calculations from MED data, Windstats Newsletter

NZ has a significant wind resource…

Source: Electricity Commission ‘Transmission to Enable Renewables’ Report

“Tranche 1”=31,230 GWh

“Tranche 1”=19,550 GWh

NZ has a significant wind resource…

…but not all of it is:

* Accessible* Available* Consentable* Economically viable

Wind in the Manawatu

Source: Electricity Commission ‘Transmission to Enable Renewables’ Report

Wind in Taranaki and the Hawkes Bay

Wind in Taranaki and the Hawkes Bay

Wind energy in the Manawatu

Seeking consent

288MWMighty River Power

Tararua RangesTuritea

Operating/ seeking consent

32.5MW (76.5MW)

NZ Wind Farms

Tararua RangesTe Rere Hau

StatusSizeOperatorLocationWind farm

Tararua Ranges

Ruahine Ranges

Operating161MWTrustPowerTararua

Operating90.8MWMeridian Energy

Te Apiti

And a bit beyond

Consented225MWHawkes Bay Wind Farms

Hawkes BayHawkes Bay Wind Farm

Consented48MWUnison & Roaring 40s

Hawkes BayTitiokura

Consented130MWMeridian EnergyTaihapeCentral Wind

Other sites under investigation

Seeking consent

177MWContact EnergyDannevirkeWaitahora

Operating8.7MWGenesis EnergySouthern WairarapaHau Nui

Policy environment> No feed-in tariffs, renewables obligations, tax

credits, capital subsidies, etc.> Price on carbon expected to allow all generation

sources to compete directly.> Non-legislated target of 90% renewable

electricity by 2025 (as long as this does not compromise ‘security of supply’).

Carbon – a view to the futureis emerging through the smog

> Electricity sector enters ETS 1st July 2010.

> 50% allocation and $25/t price cap to end-2012.

> Equivalent to fixed price $12.50/t – unlikely to be enough to drive immediate investment.

> UN Negotiations & review of ETS in 2011 means uncertainty remains.

Wind energy and the RMA

> Project Hayes adds to a sequence of inconsistent consent decisions> Experience to date with ‘call-in’ is a possible disincentive to its use in

future> Timing and decision uncertainty, together with high costs are a

potential disincentive to both developers and turbine OEMs.> RMA reform?

> balancing national & regional benefits against localised effects> resolving tension between the economic & social benefits of

infrastructure development and its environmental effects

What the industry is doing…> Establish ‘best practice’ as a route to

consistency & certainty.> Industry guidelines> Non-statutory guidance (i.e. QP)> Standards (i.e. NZS6808)

> Also seeking more robust & consistent landscape character assessment.

> Stakeholder participation critical

www.windenergy.org.nz

29-31 March, Palmerston North

Example

Process

Predict 35 dB contour

Check plan provisions

Measure background

Determine noise limits

Refine predictions

Prepare a report

Measure wind farm

Statutory processesand construction

Fictitious wind farm

District plan maps

• High country (rural) zone• Village is township zone

District plan rules

• No reference to wind farms• Reference to NZS 6802 for general noise• NZS 6802:2008 excludes wind farms

• No reference to special acoustic amenity

• NZS 6808:2010 appropriate standard

35 dB contour

Background soundBa

ckgr

ound

L A90(

10mi

n)(d

B)

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

Noise limitsBa

ckgr

ound

L A90(

10mi

n)(d

B)

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

Report

• Sound level contours (35 dB and 40 dB)

• Background sound measurements

• Noise limits

• Predictions at individual receivers

Post-installation measurements

• Repeat procedure as for background sound

• Check regression curve below noise limit

• On/off testing if necessary

• Compliance report

Summary

You now know:

• when and why there was a revision

• the project included all the key stakeholders

• the key changes between the 1998 original and 2010 revision

NZS 6808:2010 is available as a pdf or hard copy fromStandards New Zealand - www.standards.co.nz

Questions