Comparison of predicted wind farm noise emission and measured post-construction noise levels at the Portland Wind Energy Project in Victoria, Australia

摘要

During the planning phase for their approved Portland Wind Energy Project (PWEP), developers Pacific Hydro presented predicted wind farm noise emission curves in their design application. These curves were developed based on requirements of New Zealand Standard 6808:1998 Acoustics - The assessment and measurement of sound from wind turbine generators (NZS6808:1998) which was applicable at the time the PWEP Design Application was submitted. The prediction method recommended by NZ6808:1998 is based on hemispherical spreading and, as noted by the Standard, 'is generally accepted as being slightly conservative'. Several stages of PWEP are now in operation and Pacific Hydro has carried out several post-construction monitoring campaigns, in accordance with NZS6808:1998, as required by their planning permits. This paper compares the results of the post-construction monitoring campaigns with the levels of predicted wind farm noise emission which were developed during the planning phase of PWEP. An average level difference between the predicted and measured data sets is determined to quantify the conservatism in the predicted levels. In addition the prediction methods of International Standard 9613:1996 Acoustics - Attenuation of sound during propagation outdoors: Part 2: General calculation method (ISO 9613-2:1996), are considered to investigate whether they offer any significant improvements in accuracy of predictions and whether particular parameters may be identified as the source of the conservatism.