Draft National Wind Farm Development Guidelines - July 2010

D.1.2 Underlying approach
The underlying object of the following guidance is to evaluate the potential effects on key
bird and bat species, with the aim of developing a wind farm that is sited and designed to
avoid and minimise impacts.
The Guidelines encourage assessment of the potential for a wind farm development to
have impacts on birds and/or bats using an approach designed to address clearly defined
questions that will lead to an objective determination of the likely effects on particular bird
or bat populations. The underlying concept is the scientific principle of hypothesis testing,
but it is recognised that some necessary practicalities will prevail and that uncertainties are
usual in ecological impact assessments including those for birds and bats at wind farms.
The fundamental approach is the ‘Before – After – Control – Impact’ (BACI) research
design. Bird and bat use of a site can be measured before the wind farm is built and on
that basis an assessment can be made of the potential impacts it might have on important
species. Once the facility is built and operating the same measures can be used to
ascertain the real effect it has. Wherever feasible these assessments should be compared
with a ‘control’ site where no wind farm is built. Use of a control site provides the capacity
to assess whether any changes observed are attributable to the wind farm or to other
causes. Determination of an appropriate control site may be difficult in some instances
because wind farm sites are often large and contain complex habitat features so that sites
with similar features that are truly comparable may not exist. It is also the case that birds
and bats of concern are generally threatened species whose use of any given site may be
unique.
The feasibility stage component of assessment is necessarily dependent on determining
the values of the site for birds and bats prior to development of a wind farm. Conditions for
birds and bats and their use of a site may change over the life of a wind farm for various
reasons which may include responses to the wind farm. The BACI design of investigations
allows for such changes to be explored and assessed.
In harmony with the principles outlined above the objective of the Guidelines is to provide
a process that focuses evaluation of birds and bats on substantive issues, and their
resolution.
Any taxon of interest at any site will be a unique situation. The aim of these Guidelines is to
provide a framework within which choice and design of investigation and assessment
methods can be made that are appropriate to the particulars of the site and species. It is
vital that the assessment is robust and founded upon current understanding of ecology.
D.2 Background
D.2.1 Basic description of issues addressed in the Guidelines
Concern about negative effects of wind farms on birds and bats is widespread and the
issue has been raised in the assessment processes for many commercial wind farms
worldwide and for every commercial wind farm that has been proposed or built in
Australia. Principal concerns are about mortality resulting from interactions with turbine
rotors. The earliest large-scale wind energy facility at Altamont Pass in California has
experienced high levels of bird mortality, mainly of raptors. However the design of turbines
and layouts of wind energy facilities have advanced considerably since that time.
Negative impacts at modern wind farms are generally of a lower order, but bird and bat
fatalities continue to be recorded at new facilities.
This history has led to community concern and, as a consequence, the specific issue of
impacts on birds and bats is a regular facet of assessment processes for the wind energy
industry. Some reviews (e.g. Sovacool 2009), have suggested that other industries and
forms of development may have equivalent or greater effects on bird and bat
populations, but assessments for those are generally not required to quantify their effects
on birds and bats in the manner usually required of the wind industry. For example, despite
Page 114 Draft National Wind Farm Development Guidelines – 2 July 2010