Draft National Wind Farm Development Guidelines - July 2010

as detailed in Undertake attended monitoring (as required) (page 58). Lastly, derived
point measurements including sound power level testing should be considered, as
detailed in Undertake derived point measurements, including sound power level
testing (as required) (page 59).
Where non-compliance with noise level limits is reasonably confirmed, the wind farm
operator should take measures to reduce noise emission until compliance with noise level
limits is able to be demonstrated. Suitable measure may include implementation of noise
management settings and turning off particular turbines under certain weather conditions.
• Monitoring at a secondary location (as required)
Where it is believed that the background noise environment at the monitoring
location, in the absence of wind farm noise emission, may have become louder
unattended monitoring should be carried out at a secondary location.
The unattended monitoring process should be a repeat of that detailed in the above
section, with the exception that the location selected for monitoring satisfies the
following requirements:
The secondary location selected for monitoring should be the same distance
from the wind farm, be exposed to noise emission from the same wind turbines
and be of the same geographical setting as the original location. The predicted
level of wind farm noise emission should be the same at each location.
The expected background noise level, in the absence of wind farm noise
emission, should be lower at the secondary location. This may be achieved in
practice by placing the sound monitoring equipment in a nearby field or other
location that may be further away from trees or other sound sources associated
with the original location.
Undertake attended monitoring (as required)
AS4959–2010 identifies the following objectives for attended monitoring:
The procedure … below uses attended measurements at a single receiver, to
validate prediction model outputs and compliance with criteria.
Any attended monitoring should be carried out in accordance with Section 7.4 of AS4959–
2010. The procedures provided in AS4959–2010 require measurement of wind farm noise
emission as well as background noise levels with appropriate areas of the wind farm turned
off. It is noted here that such measurements would be best carried out during periods
where the background noise environment is less affected by extraneous noise sources
such as passing road traffic or agricultural activities. Depending on the location of the wind
farm, night time may be most suitable to carry out measurements.
AS4959–2010 requires attended measurements based on a critical wind speed which is
defined as “the wind speed at which there is the minimum predicted margin of
compliance with the noise criteria as set by the relevant authority.” If attended
measurements are to address a complaint rather than confirm compliance with planning
permit conditions, measurements should be based on an observed critical wind speed
which is defined as the wind speed which has been identified through discussion with the
complainant and review of their sound log/diary as being most annoying.
Recent advancements in sound level monitoring equipment have included development
of specialised equipment which is able to localise the contribution to sound level from
particular sound sources. As this type of equipment is relatively new there is, at present, no
quality control legislation, such as an Australian Standard, to verify the suitability of the
equipment.
Whilst such equipment may be useful in particular circumstances (if not to demonstrate
compliance then to identify sound sources contributing to the sound level in the area), its
usefulness may need to be discussed with the relevant authority. It should be noted that an
Page 58 Draft National Wind Farm Development Guidelines – 2 July 2010