The hills are alive with the sound of wind turbines

www.theage.com.au
December 26, 2010

REMEMBER the Orange-Bellied Parrot, the bird that briefly stopped a wind farm on Victoria's south-east coast? Well, endangered birds are so 2006 when it comes to wind farm politics. The biggest issue these days is infrasound, the low-frequency noise anti-wind farm campaigners say is generated by turbines and makes people sick.

Infrasound is the latest front in the battle over wind farms and will be investigated next year by a Senate inquiry set up by Family First's Steve Fielding. The inquiry will look at the health impacts of living near turbines and concerns over excessive noise and vibrations caused by wind farms.

Anti-wind farm campaigners say infrasound causes ''wind turbine syndrome''. Sufferers complain of nausea, dizziness and headaches. In July, the National Health and Medical Research Council reviewed the scientific evidence and found no link between wind turbines and illness.

But now one large wind farm operator has put the theory to the test on its own turbines. Pacific Hydro hired Adelaide-based acoustic consulting experts Sonus to measure the level of infrasound - created by the turbine blades moving through the air - at two farms, Cape Bridgewater in Victoria's west and Clement's Gap in the mid-north of South Australia.

As a comparison, they also measured infrasound in the Adelaide central business district and suburbs, at the beach, on a coastal cliff, inland from the coast and at a gas-fired power station. At all these places, the infrasound was not audible to the human ear. It was actually recorded at higher levels on the beach and in the Adelaide CBD Energy than it was near a wind turbine. The results for all of the places came under the internationally recognised levels a human can perceive infrasound, which is 85 - on a ''G-weighted'' scale standardised for the infrasound frequency range.

In results Pacific Hydro will send to its landholders, 67decibels (dB) was recorded 185 metres downwind of the closest operating turbine at Clement's Gap and 63dB was recorded 200 metres downwind of the closest operating turbine at Cape Bridgewater. The infrasound was a little less, 62dB, when the turbines were not turning at the Victorian site.

By comparison, 76dB were recorded for the centre of Adelaide, 75dB for the beach at Cape Bridgewater, 74dB for a gas-fired power station, 69dB for a cliff face at Cape Bridgewater, 57dB for eight kilometres inland from the Victorian coast and 51 for an Adelaide suburb.

''Infrasound is generated by a range of natural sources, including waves on a beach and against the coastline, waterfalls and wind,'' the report said. ''It is also generated by a wide range of man-made sources such as industrial processes, vehicles, air conditioning and ventilation systems and wind farms.''

The consultants, who have assessed the noise of dozens of wind farms, measured the sound with a special test chamber that stopped the results from being distorted by wind on the microphone. In response to the federal government's review of infrasound earlier this year, anti-wind farm campaigners said the review effectively said people were lying about wind turbine syndrome.

In its letter to residents who have turbines on their land, Pacific Hydro said the study was not exhaustive and is not standardised, as no standards exist in measuring infrasound.

Pacific Hydro's executive manager of government and corporate affairs, Andrew Richards, said the study would be made available and was just one contribution to the infrasound debate. He said the wind industry looked forward to presenting its case at Senate hearings next year.