Agl Energy Limited · ASX:AGL
Agl Energy — Technical Presentation (September 2012)
17 slides from Agl Energy's technical presentation, Sep 28, 2012
Slide 1: Coopers Gap CCC Meeting – Shadow Flicker
Coopers Gap CCC Meeting Shadow Flicker
Slide 2: Overview
Overview • What is shadow flicker? • What factors influence shadow flicker? • What are the characteristics of shadow flicker? • What are the impacts of shadow flicker? • How is shadow flicker calculated? • What are the limits on shadow flicker durations? • Shadow flicker at Coopers Gap GL Garrad Has
Slide 3: What is shadow flicker from wind farms?
What is shadow flicker from wind farms? Rotating wind turbine blades cast moving shadows. For an observer on the ground the moving shadows can cause a periodic variation in light levels, which is perceived as a flickering effect. Rotating blades moving shadow on the ground From Paul Gipe http://www.
Slide 4: What factors influence shadow flicker?
What factors influence shadow flicker • Relative positions of sun, turbine and observer • Time of day & day of year • Elevation angle of sun • Distance between turbine and observer • Turbine dimensions • Wind speed • Elevation • Turbine orientation • Cloud cover • Position on Earth (Latitude/Longitu
Slide 5: What are the characteristics of shadow flicker?
What are the characteristics of shadow flicker? • Shadow flicker is most noticable indoors, where the variation in light levels can be more significant. • Shadow flicker can extend a significant distance from a turbine, but may only affect an area for a short period of time. • Shadow intensity and t
Slide 6: Shadow flicker – variation with time of day
Shadow flicker – variation with time of day (standing to north of turbine, looking south)
Slide 7: Indicative shadow flicker durations
Indicative shadow flicker durations summer summer sunrise sunset winter winter sunrise sunset
Slide 8: What are the impacts of shadow flicker on people?
What are the impacts of shadow flicker on people? • “The key risk associated with shadow flicker is annoyance of residents” • The frequency of shadow flicker from a modern wind turbine is generally insufficient to affect people who suffer from photosensitive epilepsy. • “There is negligible risk ass
Slide 9: What are the impacts of shadow flicker on animals?
What are the impacts of shadow flicker on animals? • Surveys of impact on horses indicates that they may initially show a reaction to shadow flicker (e.g., standing still). • However after repeated exposures (3 to 4), affected horses typically become conditioned to shadow movements. • Many wind turb
Slide 10: How is shadow flicker calculated?
How is shadow flicker calculated? • Model containing: • Elevation data Methodology described in • Earth & sun positions and orientations EPHC Draft National • Turbine locations and dimensions Wind Farm Development • House locations Guidelines (July 2010) • Turbine rotor represented as sphere or disc
Slide 11: How is shadow flicker calculated?
How is shadow flicker calculated? • Theoretical calculation: model only • Predicted actual: assess likely reductions in shadow flicker durations due to: • Turbine orientation • Cloud Cover • Factors not considered that may reduce shadow flicker durations • Periods when turbine is not rotating • Scre
Slide 12: What are the limits on shadow flicker durations?
What are the limits on shadow flicker durations? • Shadow flicker limits (based on EPHC Draft National Guidelines) • Theoretical calculation: 30 hours per year • Predicted actual: 10 hours per year
Slide 13: Shadow flicker results
Shadow flicker results Shadow flicker map
Slide 14: Shadow flicker durations
Shadow flicker durations Theoretical Predicted Actual3 Max Within 50m of Max Within 50m of At Dwelling2 [hr/yr] House Easting1 Northing1 Dwelling2 [hr/yr] Dwelling2 [hr/yr] ID [m] [m] Contributing At 2 m At 6 m At 2 m At 6 m At 2 m At 6 m Turbines A 340083.6 7046383.9 12.5 12.5 39 13.4 13.4 6.1 6.0
Slide 15: When does shadow flicker occur?
When does shadow flicker occur? (theoretical calculation) House C House L (37 hours per year) (10 hours per year) Hour Hour 0 6 12 18 24 0 6 12 18 24 Jan-01 Jan-01 Jan-29 Jan-29 Feb-26 Feb-26 Mar-25 Mar-25 Apr-22 Apr-22 May-20 May-20 sunrise sunrise sunset Day of Year sunset Day of Year Jun-17 Jun-1
Slide 16: Mitigation of shadow flicker
Mitigation of shadow flicker • If problems with shadow flicker occur, there are a range of options available to mitigate its effects, including: • Planting trees • Installation of screening structures • Shutting down turbines when shadow flicker occurs
Slide 17: Questions?
Questions? This presentation has been produced by Garrad Hassan Pacific Pty Limited “Garrad Hassan" on behalf of and for the benefit of its client AECOM. Any opinions expressed are that of Garrad Hassan based on its knowledge of the subject matter of the presentation. Certain information is derived