An unusual noise which had eluded technicians at Pacific Hydro’s Cape Bridgewater wind farm site since September 2012 has now been identified and fixed. The noise was identified during low wind conditions, which is unusual at a site that is characterised by consistently strong winds that force trees to grow at an angle.
“We are very relieved to have finally been able to find the noise, identify its cause and solve this issue”, said Pacific Hydro general manager for Australia, Mr Lane Crockett. “Clearly the noise has been distressing for some neighbours and we feel awful to have been causing this issue for them”, said Mr Crockett. “We apologise to these neighbours.”
Mr Crockett recently travelled to Cape Bridgewater to apologise in person to the neighbours and express his hope that the company might be able to work more collaboratively with them in the future.
“We are embarrassed it took us so long to find the noise and identify its cause. While we had been investigating complaints when they were made, the specific wind conditions that the noise was audible in was not happening regularly. It seems that the noise was audible for between 30 and 60 seconds during very low wind conditions when some of the turbines were just starting up and the nacelle at the top of the tower was turning to face into the wind.”
The noise, in the higher frequency sound spectrum, was audible at up to an estimated 500m or so from some turbines during low wind conditions. The sound has been described as a screech, or a squeal by some neighbours and while not of a high volume, was at a higher pitch that was clearly out of place in the environment.
As it was an unusual and infrequent noise that is not normally made by the turbines’ operation and it has been fixed, this issue has not impacted the project’s compliance.
“Once we were able to locate and record the noise we shared it with the turbine manufacturer REpower. They have been extremely helpful in working out the cause of the noise, through testing in their factory in Germany, and have established an engineering fix to the problem”, said Mr Crockett.
Once the sound was identified Pacific Hydro arranged for all of its other wind farms to be checked. This has resulted in the identification of the same issue at our Cape Nelson South site and we are currently rectifying the issue.
“We would note that there have been no noise complaints at Cape Nelson South and the only reason we have been able to identify and fix this issue is because of our recent experience at Cape Bridgewater.”
In addition to Pacific Hydro undertaking mandatory noise compliance testing for 12 months once the Cape Bridgewater wind farm began operating in 2008, the company has also undertaken additional noise testing at the site including infrasound testing in 2010. The infrasound testing was undertaken while the wind farm was both on and off. This testing found that infrasound was present naturally in the environment and was not significantly impacted with the wind farm’s operation. As well as conducting these tests, Pacific Hydro has also offered to undertake additional infrasound testing inside a neighbour’ s house in response to concerns that were raised. It has also offered to pay for additional noise testing to be undertaken by the residents’ preferred acoustician.
The company has pledged to be more responsive to residents’ concerns and improve its transparency in the future. Pacific Hydro acknowledges that the identification and fix of this noise took far too long.
The company has also undertaken a review into the way it manages complaints and is implementing a range of changes, including new procedure and staff training, which it hopes will ensure any future concerns will be resolved more quickly and will provide a more collaborative approach to responding to complaints.
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