Page 281 - Fluid Power Engineering

248 Chapter Twelve

This chapter will start with a framework for analyzing environ-
mental impact. This is followed by description of impact on wildlife
andmethodologytoassesstheimpact.Thenextthreesectionsdescribe
the noise, shadow flicker, and aesthetic impact. Subsequent sections
describe the potentials of hazard to aviation, microwave interference,
and other electromagnetic interference. In each section, the impact,
ways to analyze the impact, and methods to mitigate the impact are
described.

Framework for Analyzing Environmental Impact
Environmental impact assessment (EIA) came out of legislation in the
United States called the National Environmental Policy Act (NEPA)
of 1969. It required all federal agencies to fully analyze environmental
effects of their programs and actions. The EIA has become a standard
practice for wind energy projects in the European Union countries.
However, in the United States, a national-level EIA does not exist for
private wind projects on nonfederal lands. It is largely up to the local
and state planning regulatory agencies to require varying degrees
of environmental assessments. Since offshore projects are on federal
lands, the Mineral Management Service (MMS) of the Department
of Interior has to conduct an EIA before allocating areas for offshore
wind farm development.
A comprehensive framework for analyzing the environmental im-
pact of a wind project does not exist in the United States. The National
1
Research Council has proposed guidelines for an analytical frame-
work, but it is not a definitive framework. The reasons are lack of data
and analytical methods to fully understand the full impact of wind
farm development on the environment: (i) Relative to other methods
of generation, (ii) for multiple temporal and spatial scales, and (iii)
as a result of cumulative actions. These three considerations must be
taken into account in any analytical framework. 1

Context of Environmental Impact
Environmental impact must be evaluated relative to the impact of
other human activities; two examples will illustrate this. First, con-
sider the noise generated by a turbine. Wind turbine that is 100 m away
generates 55 dBA of noise; a wind turbine 350 m away generates 35
to 45 dBA of noise. However, a busy office has a noise level of 60 dBA
and a busy road 5 km away generates 35 to 45 dBA of sound. When
the noise level is put in context, a more realistic picture emerges. The
second example is that wind projects kill tens of thousands of birds
each year in the United States. However, buildings and windows kill
500-plus million birds annually, transmission lines kill 100-plus mil-
lion birds annually, and domestic cats kill hundreds of millions of