Cape Bridgewater’s 29 wind energy towers have been put through rigorous testing, but operator Pacific Hydro said they don’t produce an excessive amount of noise.
Research by an Adelaide-based team of experts has shown that the infrasound from wind towers – created by the wind turbine blades moving through the air – at the cape is 63 decibels. That is less than the infrasound recorded at the beach (75 decibels on Bridgewater Beach), on the cliff face (69 decibels at Cape Bridgewater) or in the centre of a capital city (76 decibels recorded in the centre of Adelaide).
The findings parallel a study this year by the National Health and Medical Research Council. It said noise levels from wind turbines had been assessed as “negligible”. That is, they appeared to be no different to that found in other everyday situations.
“Further, a survey of all known published results of infrasound from wind turbines found that wind turbines of contemporary design, where rotor blades are in front of the tower, produced very low levels of infrasound,” the NHMRC reported.
Pacific Hydro is sending a mail-out to all its landholders, offering a summary of the expert findings.
Opponents of wind farms have said that some people who live near them suffer headaches, nausea and dizziness. Tests by both the acoustic measuring company and the NHMRC could not establish any link. However researchers were unable to say if some people might be more vulnerable, for whatever reasons, to low-level sound, or if some unknown other factor might be contributing to the illnesses.
Pacific Hydro has told residents who have turbines on their land that the study was neither exhaustive nor final, because there is no recognised standard for measuring infrasound.
At Cape Bridgewater, the 63-decibel reading was taken 200 metres from the turbine. By comparison, when the turbines were not turning, the infrasound was 62 decibels.
The testing team said infrasound is also produced by airconditioning systems, cars and industrial plants. It will be the subject of a Commonwealth Senate inquiry chaired by the outgoing Family First Senator Steve Fielding early next year. Besides noise, the enquiry is also expected to look at the issue of sunlight hypnotically reflecting off of turbine blades.
The NHMRC report included a brief reference to a link they said their research team had found between those who complain about the noise and those who disliked the visual appearance of the towers.
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