Agl Energy Limited · ASX:AGL
Agl Energy — Technical Presentation (November 2012)
38 slides from Agl Energy's technical presentation, November 2012
Slide 1: Silverton Wind Farm Presentation on Noise
Silverton Wind Farm Presentation on Noise Rhys Brown November, 2012
Slide 2: Agenda
Agenda - Discuss some general principles related to noise and wind farms - Review the process: • Background noise monitoring • Noise modelling and forecasting • Determining compliance - What does a wind farm sound like? - Questions and Discussion Silverton Wind Farm December 13, 2012 Page 2
Slide 3: Wind farm noise
Wind farm noise - Wind Farms only generate noise when the wind is blowing at sufficient speed to generate electricity - Is typically assessed and measured using specific guidelines which take this into consideration - The two primary noise generating mechanisms are mechanical noise (gearbox, generat
Slide 4: Classification of noise
Classification of noise - dB(A) or “A-weighted” – audible frequency range between 20Hz – 20 000Hz. Weighting applied to represent how humans hear sounds - “Low Frequency Noise” – used to describe noise at the low end of the human hearing range, often categorized between 20Hz – 200Hz - “Infrasound” –
Slide 5: Silverton Wind Farm December 13, 2012 Page 5
Silverton Wind Farm December 13, 2012 Page 5
Slide 6: Silverton Wind Farm December 13, 2012 Page 6
Silverton Wind Farm December 13, 2012 Page 6
Slide 7: Why are wind farms assessed using specific guidelines?
Why are wind farms assessed using specific guidelines? - Wind Farms only generate noise when the wind is blowing at sufficient speed to generate electricity, and they typically generate higher noise levels during periods of high wind - They differ from most other sources of environmental noise emiss
Slide 8: Silverton Noise Criteria
Silverton Noise Criteria - Operational noise criteria for Silverton is outlined in clause 2.20 of the Project Approval and is based on the South Australian “Wind Farms Environmental Noise Guidelines” 2003. • 35 dB(A); or • The existing background noise level (LA90 (10min)) by more than 5 dB(A), corr
Slide 9: Development of criteria for wind farms
Development of criteria for wind farms - Criteria for environmental noise is often developed based on background noise levels, guidelines for noise levels for the protection of the general population, or a combination of both - The World Health Organization and others set such guidance for the prote
Slide 10: Noise reduction of a façade with open windows
Noise reduction of a façade with open windows - When sound hits a façade, the energy is either transmitted into the house, absorbed by the building or reflected back towards the source - The World Health Organization provides a estimate of a 15dB reduction from outside to inside with a partly open w
Slide 11: Noise reduction of a façade with open windows
Noise reduction of a façade with open windows - A review of literature consistently shows that the assumption of a 10 dB(A) reduction for an open or partially open window is an appropriate assumption for a majority of dwellings - In excess of the 5 dB(A) required to satisfy the WHO guideline for int
Slide 12: Industrial Noise Assessment Process
Industrial Noise Assessment Process - Background noise monitoring – determining the existing environmental characteristics - Noise Predictions/Modelling – Predicting the impacts from the proposed industry - Compliance – Once industry is operating, checking if the operation is in compliance with it’s
Slide 13: Background noise monitoring
Background noise monitoring Possible wind turbine location Silverton Wind Farm December 13, 2012 Page 13
Slide 14: Background noise monitoring
Background noise monitoring - Background noise monitoring was undertaken in November – December 2007 by acoustic consultancy Heggies Pty Ltd - Undertaken at three locations considered representative of the closest locations to proposed turbine locations Source: Silverton Wind Farm Noise Impact Asses
Slide 15: Background noise monitoring
Background noise monitoring Source: Silverton Wind Farm Noise Impact Assessment Report 40-1487 Heggies Pty Ltd Silverton Wind Farm December 13, 2012 Page 15
Slide 16: Noise predictions/modelling
Noise predictions/modelling - Undertaken to determine if the proposed wind farm layout can be constructed and comply with noise criteria - Undertaken to inform the area required to construct a wind farm Silverton Wind Farm December 13, 2012 Page 16
Slide 17: Noise modelling process
Noise modelling process - Is undertaken using a computer modelling package - Is based on a number of inputs and assumptions - The modelling is conservative as some effects which could reduce noise levels are not included in the model, including: • Shielding from buildings • Reduction due to dense fo
Slide 18: Noise modelling inputs
Noise modelling inputs Input Source Topography Ground contours generated by a laser survey (typically at a 1 metre resolution) Noise source data Typically taken from a contract entered into with a turbine supplier Source location (turbines) Developed as the project has progressed, represents the phy
Slide 19: Noise modelling process
Noise modelling process - Noise modelling methodologies used for modelling wind farm noise are validated by modelling the noise emission from existing wind farms and comparing the results against noise levels measured at the same wind farms - AECOM undertook one such study which compared four modell
Slide 20: Noise modelling process
Noise modelling process - Blue = turbine hub height, Black and White ball = house Not to scale Silverton Wind Farm December 13, 2012 Page 20
Slide 21: Predicted noise levels
Predicted noise levels Source: Environmental Assessment (EA) prepared by Silverton Wind Farm Developments Pty Ltd (www.agk.com.au/silverton) Silverton Wind Farm December 13, 2012 Page 21
Slide 22: Occurrence of worst case forecast noise levels
Occurrence of worst case forecast noise levels - Computer modelling is based on the worst case forecast noise level - In reality the noise from the wind turbines will be reduced under different wind conditions, e.g. with wind blowing perpendicular to the line in between the nearest turbine and recei
Slide 23: Worst case wind direction
Worst case wind direction Plan View – Sketch is not to scale Silverton Wind Farm December 13, 2012 Page 23
Slide 24: Infrasound noise levels
Infrasound noise levels - Infrasound categorized between 0 – 20Hz - Infrasound is audible only at very high levels - Studies have shown that other parts of the body do not respond to infrasound below the audible range - Noise assessment stated that • “It is noted that, in general, modern WTGs do not
Slide 25: Infrasound noise levels
Infrasound noise levels - Infrasound levels predicted to be inaudible outside of 200 metres from a turbine Source: “Infrasound measurements from wind farms and other sources” – Sonus Pty Ltd Silverton Wind Farm December 13, 2012 Page 25
Slide 26: Compliance Monitoring – once wind farm is operating
Compliance Monitoring – once wind farm is operating - Once the wind farm is operational, it must comply with its operating conditions outlined in the Project Approval - Compliance monitoring determines if a constructed wind farm is operating in accordance with its operating conditions, this is based
Slide 27: Determining Compliance
Determining Compliance • The Noise Compliance Plan will cover off such information as: • Monitoring methodology (SA 2003) • Locations for monitoring • Assessment of Special Audible Characteristics (SACs) • The Project Approval also contains conditions on the proponent should the measured noise level
Slide 28: Compliance Monitoring – once wind farm is operating
Compliance Monitoring – once wind farm is operating - Compliance monitoring procedures are described in SA2003 guidelines - It is common for compliance monitoring to be undertaken in the same or similar locations to background logging locations Silverton Wind Farm December 13, 2012 Page 28
Slide 29: Compliance Monitoring – once wind farm is operating
Compliance Monitoring – once wind farm is operating - Noise monitoring undertaken after a wind farm is constructed will capture a combination of wind farm noise and background noise Existing Ambient Noise data taken from background noise measurements at a location adjacent a proposed wind farm Silve
Slide 30: Compliance monitoring calculation procedure
Compliance monitoring calculation procedure - A minimum number of 2000 10-minute data points are required under SA2003 - Compliance checking should collect data associated with the worst case wind direction from the wind farm to the relevant receiver - Regression (averaging) is then undertaken on th
Slide 31: Compliance monitoring calculation procedure
Compliance monitoring calculation procedure Silverton Wind Farm December 13, 2012 Page 31
Slide 32: Compliance monitoring calculation procedure
Compliance monitoring calculation procedure Silverton Wind Farm December 13, 2012 Page 32
Slide 33: Compliance monitoring calculation procedure
Compliance monitoring calculation procedure Silverton Wind Farm December 13, 2012 Page 33
Slide 34: Compliance monitoring calculation procedure
Compliance monitoring calculation procedure Silverton Wind Farm December 13, 2012 Page 34
Slide 35: Compliance monitoring calculation procedure
Compliance monitoring calculation procedure Silverton Wind Farm December 13, 2012 Page 35
Slide 36: What does a wind farm sound like?
What does a wind farm sound like? - At the base of the turbine the noise from a wind turbine is approximately 60 - 65 dB(A) - LAeq noise exposure from standing at the base of a turbine for 8 hours continuous is around 20 dB(A) below the exposure limit for occupational health and safety noise - At a
Slide 37: What does a wind farm sound like?
What does a wind farm sound like? - Demonstration of wind farm sound levels - Recording was taken outside a house approximately 1.5 kilometres from a large wind farm in South Australia - Was selected for this demonstration due to minimal background noise (e.g. wind through trees, birds, crickets etc
Slide 38: Thank You
Thank You Rhys Brown rhys.brown@aecom.com (07) 3553 3078