The Waterloo Wind Farm Study was established with the specific purpose of investigating any physical basis for descriptions by members of the surrounding community of the noise around the wind farm. To that end, the focus was on the houses of volunteers who had expressed strong views about noise from the facility. The study was not therefore designed to be a comprehensive evaluation of the noise environment at all areas around the wind farm, and is not intended to be a study of health impacts. Measurements were supplemented by information supplied in weekly diaries, kindly submitted by volunteers in the community, both the hosts of monitoring equipment and other householders in the area.
In measuring noise and supporting meteorological parameters, the EPA aimed to provide the widest coverage of the noise spectrum with the available resources. Audio noise and infrasound (0.25Hz to 20 kHz) were measured inside and outside two houses; while audible noise, including the ‘Extended Low Frequency Band’ was measured at the remaining houses, covering 12.5Hz to 20kHz.
To further facilitate separation of wind farm noise signals from background noises, the wind farm operators cooperated in shutting the entire facility down on six occasions to provide periods when operation of the wind farm itself could be eliminated as a source of noise. On each occasion the wind farm was shutdown only under conditions established by the EPA, which would otherwise allow its normal operation; that is, when wind speeds were within the range at which electricity generation would have been viable.
For the purposes of this report, periods when wind speeds were less than threshold for operation of the turbines, that is under calm conditions or very low wind speeds were not considered to be ‘shutdowns’.
The report incorporates broad discussions of the design and implications of the study findings in Sections 1 to 3, with detailed data and analyses presented in Section 4.
Wind power in South Australia
Wind power is a significant source of renewable energy within South Australia. To date, 15 wind farms have been constructed across the state, some of them are multi-stage developments. Total generating capacity of South Australian wind farms exceeds 1.2 GW which is equivalent to approximately 41% of the nation's installed wind capacity.
To date, wind farms have been installed in diverse regions across the state, especially the South East and Mid North regions.
Significant proposals to increase South Australia’s wind power generation capacity have been developed, most notably the CERES Project on the Yorke Peninsula.
Waterloo Wind Farm
The Waterloo Wind Farm is located in the Mid North, approximately 100 km north of Adelaide, the state capital of South Australia. The facility lies approximately 20 km south of Burra (the nearest major town), and 3.5 km to the east of the small township of Waterloo (from which it derives its name). Situated atop a north–south ridge, and stretching for 18 km, the wind farm comprises 37 Vestas V90 3 Megawatt wind turbine generators, each having a hub-height of 80 m, with the entire site having a rated generation capacity of 111 Megawatts. Major technical parameters of the wind turbine generators are summarised in Appendix A . The turbine does not exhibit any tonal characteristic in accordance with results of tonality tests [7, 23].
The Waterloo Wind Farm was commissioned and commenced operation in 2011, having gained development consent from the Clare and Gilbert Valleys District Council in 2009.
Following commissioning of the Waterloo Wind Farm, persistent complaints have been raised referencing noise issues, infrasound issues, health complaints, effect on livestock (most notably poultry), and effect on visual amenity among others.
A post-construction noise monitoring report  confirmed compliance of the wind farm with conditions of the development approval. Additional noise monitoring at other locations in the area was commissioned by the wind farm operator in response to complaints of some of the residents regarding noise from the wind farm.
The EPA conducted spot checks of reported noise levels using attended measurements at the North East site and other points near the wind farm (Figure 3). These tests were never intended to be comprehensive studies, but were aimed at providing some confirmation of whether figures recorded in consultants’ reports could be reproduced under similar conditions. To provide some comparability of data, the days chosen for these tests were specifically based on forecasts of similar weather conditions.
For these exercises, the noise monitoring and data analysis were based on A-weighted levels. The investigations found no evidence that A-weighted noise levels from the wind farm might have been excessive.
As noted previously, the design of the current study included a broader range of acoustical descriptors, weather information and weekly diary returns from volunteer residents.
The project was established with the specific purpose of investigating four primary questions about effects of the wind farm:
- Is there a physical basis for descriptions of noises supplied by members of the community?
- Are there particular environmental conditions that evoke complaints?
- Are low frequency and infrasound components present and do they contribute to these described effects and complaints?
- Do the criteria in the Wind Farm Environmental Noise Guidelines 2009 need to be reviewed?
In accordance with a commitment made to the Waterloo community, the project comprised continuous monitoring of noise at various strategically selected sites in the region surrounding the Waterloo Wind Farm, and subsequent data analysis.
Broadly, the approach adopted for the study is summarised as follows:
- Maintaining a clear focus on houses where residents have expressed concerns about noise; and utilising descriptions supplied by residents to the EPA as a basis for investigations.
- Undertaking simultaneous acoustic and weather measurements, with concurrent noise measurements inside and outside houses.
- Implementing a broad-based community noise diary program, in which both hosts of equipment and other community members could participate, to supply essential data on perceived impacts of noise.
- Inclusion of full-scale wind farm shutdowns under typical power generating conditions within the monitoring period.
- Using all available tools to detect noise from all sources in the area, including general wind-induced noise, other ambient sources (eg farm machinery, internal appliances, household activities), and the wind farm itself on a comparative basis, including amplification of audio records to facilitate analysis.
- Providing as much information to the community as practical during the study period.
As the project aimed to investigate concerns expressed by residents, monitoring sites were selected according to where those where residents had identified an impact. This approach was chosen—rather than attempting to compare ‘affected’ and ‘non-affected’ sites—to maximise the focus on specific descriptions of noise around the wind farm, and to optimise the use of relatively limited resources.
Furthermore, to ensure that information on the noise environment reflected as far as practical the experience of residents, noise measurements were undertaken concurrently inside and outside each of the residences selected for noise monitoring (except the East site). Weather data was also gathered at each site to facilitate analysis of the noise measurement data, as were diary records supplied by residents outlining times they were affected by the wind farm noise.
The scope of the study was expanded to explore potential for noise impact in the infrasound frequency range (down to 0.25Hz as defined in international standard ISO 7196 ) and the extended low frequency band, down to 12.5Hz.
The study was never intended to be a comprehensive survey of the noise environment around the Waterloo Wind Farm, or a health study.
The aim of the study was to investigate whether a physical, scientific basis could be shown for descriptions of noise by residents near the Waterloo Wind Farm, so the focus of available resources was specifically directed to answering that question, rather than attempting to characterise the broad noise environment of the area.
For similar reasons, a consideration of health impacts was not part of the analysis. However, community members were entirely free to provide information through the diary returns on the effects they felt during the study period, and any other factors that they considered important; and many have done so. Proper evaluation of these health-based descriptions falls under the purview of health authorities, and the EPA will refer the information to relevant authorities as soon as practical.