Draft National Wind Farm Development Guidelines - July 2010

considered acceptable, undesirable, or unacceptable and can be expected to lead to
one of the following outcomes:
• If relevant authorities consider predicted impacts on key species population(s) to be
acceptable, the feasibility stage assessment process for birds and bats will generally
be complete at this point.
• If the level of impact is considered to be undesirable by relevant authorities, but not
to have totally unacceptable implications for the population of the key taxon,
consideration must be given to mechanisms to reduce or mitigate impacts to a lower
level. This will entail proceeding to the following phase of the assessment process.
• If relevant authorities consider the projected mortality or other effects to be
unacceptable, a review of the wind farm proposal should take place to determine
whether it is appropriate for assessment processes to proceed.
Assessment of any reduction or mitigation of impacts that can be achieved
If, based on the preceding assessment phases, the level of impact is considered to be
undesirable, planning and design of the wind farm may be able to be altered to reduce or
mitigate predicted collision effects. Any such re-design should be incorporated into the
basic inherent design of the proposal as ‘passive’ measures aimed at reduction of risks.
Principal question:
Purpose:
Methods:
What, if any, reduction or mitigation of potential impacts can be achieved
To utilise information gained through the assessment process thus far to guide
final design of the wind farm aimed at further reduction of impacts on key
species.
Wind farm redesign, if applicable.
Re-design measures are dependant upon different site characteristics and key species.
Examples of re-design measures that have been applied at some sites in Australia include:
• Redesign to preferentially site turbines into areas of the site posing least danger to key
taxa.
• Reduction of the number of turbines.
• Identification and establishment of appropriate, infrastructure-free buffers around
locations of habitat resources of importance or attraction to key taxa.
• Changing the model of turbine to be used or altering hub height.
• Consideration of requirements and design for aviation warning lighting
A note about aviation warning lighting
Aviation warning lights may be required on turbines and meteorological masts at a wind
farm. Civil Aviation Safety Authority (CASA) Manual of Standards provides information
relevant to obstacle lighting.
Artificial lights on tall structures can be disorienting to birds and the cause of disabling
responses that may ‘trap’ large numbers of birds within a pool of light. Lights may also
attract insects that are prey for bats. There is thus potential for aviation lighting to
exacerbate collisions risks for birds and bats. An empirical study of lighting on towers
(Gehring et al. 2009) found that the use of flashing or strobe lights substantially reduced
attraction of birds to tall structures when compared with steady burning lights. The colour
of flashing or strobe lights (red or white) made no significant difference to results.
Page 128 Draft National Wind Farm Development Guidelines – 2 July 2010