Cooper findings

Acoustician, Steven Cooper, has been asked to measure noise emissions at the Cape Bridgewater wind energy facility in Australia following years of noise complaints since the project was placed in service in 2008. Mr Cooper has tested inside three homes near the wind facility over eight weeks, including a two-week shutdown of the turbines. His preliminary report can be accessed by clicking the link(s) on this page. His initial findings are provided below.

Preliminary Findings to Date

• At none of the house has the dB(G) been above 85 and therefore if that level has taken as the hearing threshold of infrasound then there is no audible infrasound in any of the houses

• The presence of the wind turbine signature, which is related to the blade pass frequency and multiple harmonics of that frequency, is readily identified inside dwellings and at times outside dwellings.

• The wind turbines signature does not exists when the turbines are not operational.

• The use of 1/3 octave band information to compare infrasound generated by turbines and the infrasound in the natural environment does not contain the required information to identify any difference. When supplemented by narrow band analysis of the infrasound region the results clearly show that the natural environment of infrasound has no such periodic patterns.

• Electrical interference/surges in mains + very strong winds has created problems with some data collection.

• The significant amount of data that is available from the monitoring will require further time for detailed analysis in view of issues that have been raised by the residents during the course of the monitoring and the findings to date.

• Analysis of vibration measurements around and inside houses is yet to be undertaken.

• Basic material is to be presented looking at the pitch angles etc. during certain time periods for further analysis by Pacific Hydro and its turbine suppliers.

• The resident’s observations and identification of sensation separately to vibration and noise indicates that the major source of complaint for the operation of the turbines would appear to be related to sensation rather than noise.

Cooper Preliminary Findings Cape Bridgewater

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AUG 6 2014
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