Draft National Wind Farm Development Guidelines - July 2010

In practice, assessment of shadow flicker in Australia generally refers to the Victorian
guideline to provide some limit to assess against.
Under these standards, there is considerable scope for variation in the method used in the
assessment. These Guidelines aim to resolve this situation, and to provide a consistent
approach for assessment.
International
International regulations vary widely. By far the most comprehensive and well researched
regulations are implemented in Germany. These are described in German Ministry for
Environment and Climate Change (2002). These regulations included detailed limits:
• 30 hr/yr and 30 min/day modelled shadow flicker
• 8 hr/yr actual shadow flicker
• Limits apply within a distance of 2 km of the turbine or where there is a 20% blockage
of sunlight.
They also include a detailed method and assumptions to be used in calculations including:
• Minimum angle of the sun above the horizon of three (3) degrees
• Model the Sun as a point
• Include effects of topography
• Do not adjust for atmospheric refraction
• Receptor height 2 m above ground (or window height)
• Receptor locations. all dwelling entry points (windows and balconies)
• Document assessment for at least a one year period (365 days, 24 h/day
Possible mitigating circumstances and supporting evidence for limits and approaches is
also included.
Other international standards and regulations are discussed in further detail in Section E.7.1.
E.3 Overview of the Methodology
The method aims to address and limit the impact of shadow flicker on amenity of residents.
The following points provide an overview of the method:
• Developers may use .rules of thumb. for selecting wind farm sites that have a
reasonable chance of satisfying shadow flicker requirements; however, these do not
ultimately factor in the technical requirements of these Guidelines and so are not
included in these Guidelines.
• The method provides criteria to identify the region around turbines within which
shadow flicker is considered to have the potential to cause annoyance. Only
residences inside this region require detailed assessment. The size of the region is
specified in Section E.4.3.
• The method specifies annual duration of shadow flicker at a residence as the
performance measure for assessing shadow flicker impacts. See Section E.4.3 for these
limits.
• The method describes a complete set of modelling assumptions and allowable
mitigations enabling consistent calculation of the duration of shadow flicker at
affected residences (see Section E.4.3).
Page 150 Draft National Wind Farm Development Guidelines – 2 July 2010