Draft National Wind Farm Development Guidelines - July 2010

E.4.4
Construction
Assessment of the micro-sited layout
Shadow flicker is very sensitive to turbine position. Micro-siting, even within the limits
allowable for an approved development application, can significantly change the
duration of shadow flicker at some locations. Following micro-siting, shadow flicker should
be reassessed, as described in Section E.4.3.
The revised assessment should be submitted to the relevant authority.
If the assessment of the micro-sited layout results in the exposure limits being exceeded,
mitigation measures should be introduced.
E.4.5
Operations
Assessment of the actual shadow flicker
The limits and method recommended in these guidelines are such that complaints from
affected residents are unlikely. In the event that complaints do arise, the following actions
are recommended.
Independent modelling of shadow flicker, using as-constructed turbine positions, should be
carried out according to the method presented in Section E.4.3 noting that this need only
be carried out once, regardless of the number, timing and source of complaints. In the
event that this shows the wind farm does not comply with these Guidelines, mitigation
strategies such as planting of vegetation or scheduling turbine operation should be
implemented to achieve compliance (see Section E.4.3).
In the event where a complainant is not satisfied by the outcome of this approach, an
observational study may be recommended. It is difficult to determine the level of shadow
flicker observationally, because of the range of variables (especially cloud cover) that will
reduce the duration below that modelled. Additionally, a full years monitoring against
which the annual exposure can be judged is likely to be impractical. As an alternative, it is
recommended that observational study of shadow flicker on one day (when shadow
flicker is present and there is no cloud cover) be carried out. This should be carried out
using a video recorder placed at the receptor and monitored by an independent
observer. A comparison of the time and duration of shadow flicker on that day would
effectively validate or invalidate the predictions of the shadow flicker model, (which will
need to be modelled for the same day). Validation of the model (within a tolerance of ±3
minutes) should be considered to demonstrate compliance with these Guidelines.
In the unlikely scenario where a wind farm is shown to comply with these Guidelines but a
sensitive resident is still annoyed by the shadow flicker, the resident should be
recommended to take the following steps:
• Plant screening vegetation between their property and the turbine(s).
• Install heavy blinds or shutters on affected windows.
E.5 Practice notes
E.5.1
Cumulative impacts
The approach to addressing cumulative impacts is common to many aspects of wind
farms. This section addresses requirements specific to shadow flicker, and in particular
defines the information to be provided by a developer in order to assess potential
cumulative impacts in the future. Cumulative impacts from shadow flicker are generally
unlikely; however, there are a number of practical instances where they can occur and so
the potential for such impacts to arise should be addressed.
Draft National Wind Farm Development Guidelines – 2 July 2010 Page 155