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.