HEALTH impacts caused by
low-frequency noise from wind turbines have been known to US researchers
and the renewable energy industry for more than 25 years.
American researchers used mock homes, big speakers and seven
volunteers to simulate and measure the impact of low-frequency noise
produced by early model, two-blade wind turbines under controlled
conditions.
A November 1987 report prepared for the US Department
of Energy said the impact of low-frequency noise generated by wind
turbines was often "confined to within surrounding homes" and that
residents became more sensitive to the impact over time.
The laboratory experiments found that "people do indeed react to a low-frequency noise environment".
The
study, A Proposed Metric for Assessing the Potential of Community
Annoyance from Wind Turbine Low-Frequency Noise Emissions, was prepared
in response to earlier research into "acoustic disturbances" associated
with the operation of a wind turbine near Boone, North Carolina.
It found that the standard A-weighted measure for sound was "not an
adequate indicator of annoyance when low frequencies are dominant".
The
research was sent by an American acoustics expert to Australian wind
health campaigners and has now been published internationally.
The
US report built on earlier research by two NASA facilities and several
universities. It was presented to the Windpower 87 Conference &
Exposition in San Francisco by physicist ND Kelley from the Solar Energy
Research Institute in Golden, Colorado.
Wind health groups in the
US and Australia said although modern wind turbines were different to
the one studied, the 1987 research was significant because industry
noise-testing regulations had been specifically designed to exclude
testing inside buildings and did not concentrate on low-frequency noise
-- the two main issues identified in the report.
A federal Senate inquiry recommended two years ago that in-house testing be conducted in Australia but it is not included in the present noise guidelines.
Clean Energy Council policy director Russell Marsh said the study was not relevant to modern turbines.
"This is the equivalent of taking a study about Ataris and applying it to the latest iPads," Mr Marsh said.
The
US research was conducted on older-model wind turbines which the CEC
said were known to have noise problems as the blades were exposed to
airflow patterns caused by the wind swirling its way through the
supports of the trestle tower structure before flowing on to the blades.
"Australia
has some of the toughest noise guidelines for wind power anywhere in
the world and there is a growing body of more recent evidence that wind
turbines do not produce enough low-frequency noise or infrasound to
directly cause health problems," Mr Marsh said.
But other research
has shown that as wind turbines get larger, a greater proportion of the
sound is emitted in the lower frequency range.
"The (US) research
is highly relevant, even though the acoustic emissions themselves are
different between old downwind turbines and upwind ones, where the
turbines turn around to face into the wind," Waubra Foundation chief
executive Sarah Laurie said.
"What is important is the impact on
the people from the sound energy emitted from the respective wind
turbines, how it is experienced by them inside their homes and the
acknowledgement that the symptoms are real, and that the symptoms may be
perceived but not heard," Dr Laurie said.
Health campaigners said
the results of the laboratory simulations in the US study proved there
was a direct cause-and-effect relation between the low-frequency noise
and "annoyance".
The National Health and Medical Research Council
has said there was no published evidence linking wind turbines to health
impacts. The NHMRC is conducting a review of its advice but its updated
report on the issue is now overdue. The South Australian Environmental
Protection Agency has recently completed a major sound monitoring
program at Waterloo where there have been significant complaints from
residents, but the results are not yet available.
theaustralian.com.au 9 July 2013
Governments are fully aware of the many dangers to environment and people with respect to certain alternative energy sources.
Since these alternatives are great moeny spinners, certain information is kept from the public in order to keep the businesses created flowing, at the expense of the health of the general population, and NOT the policy makers.