In South Australia wind farm approvals are processed through the planning system, where planning approval requires assessment and management of noise impacts. The EPA provides advice (not direction) to planning authorities in accordance with the EPA Wind Farms Environmental Noise Guidelines 2009 (the Guidelines).
The Guidelines were revised in 2009 following extensive consultation with community and industry groups, using the best information available. The Guidelines are among the strictest in the world and were predicated strongly on health advice from the National Health and Medical Research Council (NHMRC) and the Department for Health and Ageing.
Once approved, wind farms are not licensed by the EPA, but the EPA does retain regulatory power through the General Environmental Duty in Section 25 of the Environment Protection Act 1993. Every wind farm in SA has had a noise impact assessment undertaken at pre- and post-construction phases by independent acoustic consultants. Repeated short-term conventional measurements at receptor locations near SA wind farms have failed to show any signals that would not meet current criteria in the Guidelines. However, claims of serious health impacts persist in SA, nationally and internationally.
The Guidelines were utilised for the assessment of Waterloo Wind Farm, which was commissioned in 2011. Post-construction noise monitoring has confirmed compliance of the wind farm with conditions from the development approval (from the Clare and Gilbert Valleys Council).
In December 2012, EPA officers met with residents from Waterloo to discuss their concerns regarding the wind farm. Concerns included a rumbling noise and a variable pulsing noise that was dependent on wind direction. The residents spoke of various symptoms such as headaches, sleep disturbance and exhaustion, flu-like symptoms and tinnitus.
In January 2013, the Chief Executive of the EPA, Dr Campbell Gemmell and Operations Director of Science, Assessment and Planning, Mr Peter Dolan, visited the Central Local Government Region of SA to meet with a delegation of Mayors regarding wind farms in the area. They also met with members of the Waterloo and Districts Concerned Citizens Group on the matter.
What did the study set out to achieve?
Following the meeting with residents in December 2012, the EPA decided to undertake an independent study investigate the concerns of the community regarding noise from the Waterloo Wind Farm. In particular, the EPA sought answers to four primary questions, maintaining a particular focus on infrasound and low frequency noise:
- 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 South Australian Wind Farm Environmental Noise Guidelines need to be reviewed?
The EPA’s Waterloo Wind Farm Noise Study had two components; a noise and weather monitoring component, and a community diary component:
From April to June 2013, the EPA undertook noise and weather monitoring at 6 locations at distances of 1.3 to 7.6 km and a range of directions from the Waterloo Wind Farm (see map):
- At 2 locations, indoor and outdoor monitoring was undertaken for noise in both the infrasound (0.25Hz to 20Hz) and audio (20Hz to 20kHz) frequency ranges.
- At 3 locations, indoor and outdoor monitoring was undertaken for noise in the audio frequency range (~12Hz to 20kHz)
- At 1 further location, outdoor monitoring was undertaken for noise in the audio frequency range (~12Hz to 20kHz).
During the study, the EPA received weekly noise diaries from residents who volunteered to participate in the study.
The owner and operator of the Waterloo Wind Farm, Energy Australia, also provided operational and meteorological information to the EPA, as well as organising, on request, six shutdowns of the wind farm under conditions when power would normally be generated.
The project design was based on a set of broad principles, including:
- 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 investigation.
- Simultaneous acoustic and weather measurements, with concurrent noise measurements inside and outside the houses.
- A broad-based community noise diary program to supply essential data on perceived characteristics of noise.
- Full-scale wind farm shutdowns under typical power generating conditions.
- Detection and characterisation of noise from all sources that may contribute to the noise environment.
- Provision of as much information to the community as practical during the study period.
As the project aimed to investigate concerns expressed by residents, monitoring locations were selected according to where residents had identified concerns. This approach was chosen—rather than attempting to compare ‘affected’ and ‘non-affected’ locations—to maximise the focus on specific descriptions of noise around the wind farm, while optimising the utility of relatively limited resources.
The diaries were essential in focusing analyses on particular events; and EPA is grateful for the willing participation of the community in providing this information. In fact at times, diary returns assisted EPA to understand some specific noise characters that were otherwise very difficult to detect,
What the study did not do …
The study was never intended to be either a comprehensive survey of the noise environment around the Waterloo Wind Farm, nor a health study.
The focus of available resources was specifically directed to whether a scientific basis could be found for descriptions of noise events by community members, rather than attempting to characterise the broad noise environment of the area.
Given this, a consideration of health effects 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 more within the purview of health authorities, and EPA intends to refer the information to relevant authorities as soon as practical.
Noise and meteorological monitoring were continued over two months from mid-April to mid-June 2013. Noise diaries from the respondents living in the general Waterloo area were utilised for analysis of noise events. These were cross referenced to acoustical data, weather parameters and audio records.
What were the findings of the study?
- Noise events that could be attributed to the wind farm were periodically audible at four locations, but at very low levels, which did not dominate the noise environment; however, no attributable events were found at the two remaining houses.
- Where detectable, noise levels from the wind farm were found to comply with criteria in the EPA Wind Farm Environmental Noise Guidelines.
- Wind farm operation was shown to contribute to the low frequency content of noise under some operating and environmental conditions, resulting in an increase in relevant low frequency noise descriptors
- In those houses where infrasound was monitored, a ’blade pass frequency‘ component was found at levels significantly below the accepted perception threshold of 85dB(G).
- Background noise resulting from local winds and other noise sources, was shown to contribute to increases in low frequency noise that were comparable with, or higher than contributions from the wind farm.
- A ‘rumbling’ effect was found using diary records to focus the analysis, which could only be heard with amplification of audio records.
- In many cases, the EPA was unable to attribute events described in noise diaries to the turbines; and at times reported events coincided with shutdowns of the plant.
- Some degree of modulation was detected, which may have been perceivable at times by residents.
- The rumbling and other low frequency characters found in this study would not generally be audible to a typical listener, but it is possible that sensitive people living within this very quiet area may hear them. This could cause annoyance to some people if exposed to the noise for prolonged time periods.
What are the implications of the study findings?
The Waterloo Wind Farm meets relevant South Australian and international standards, and is compliant with the South Australian wind farms noise guidelines.
On the basis of the physical results of this study, the EPA considers that noise from the wind farm may be audible to sensitive listeners at times, particularly under ‘downwind’ conditions. However, the EPA does not consider that there is sufficient evidence from the physical measurements of noise, to warrant a review of the Wind Farm Guidelines.
The EPA relies on advice from health authorities in setting guidance for noise and other forms of environmental emissions, and notes that there is a review underway by the National Health and Medical Research Council into the possible health effects of wind farms.
If information becomes available to indicate that further review of the Wind Farm Guidelines may be needed, the EPA will of course consider that evidence in conjunction with relevant health authorities.