Response to South Australian Environment Protection Authority Draft for consultation, Wind farm environmental noise guidelines 2019
The Australian Wind Alliance is a community advocacy group for wind energy with members across the country, who are a mix of farmers, wind workers, local businesses and community members. We advocate for greater uptake of wind energy to deliver economic benefits to regional Australia and clean up Australia’s energy supply. We represent a community voice of support for wind which is distinct from that of industry.
The Australian Wind Alliance welcomes the opportunity to respond to the EPA’s draft wind farm noise guidelines.
We acknowledge the need for periodic review of the guidelines. Updated World Health Organisation guidelines and the need to keep up with current development practices, such as staged wind farm developments, warrant regular revisions to ensure the guidelines remain appropriate to balance the need for new wind farms and the benefits they bring for local communities with protection of amenity for nearby residents.
Wind’s strong record in South Australia
We note that since the last review of the guidelines in 2013, up to twenty wind farms have operated continuously in South Australia, with a very low level of complaints about noise. The National Wind Farm Commissioner commenced complaint handling in 2016 and publishes detailed data on those complaints in his Annual Reports. In the 2017 report, he notes one complaint for a South Australian wind farm for the year, without specifying whether or not it was for noise. In the 2018 report, there is not a single complaint for a South Australian wind farm, in regard to noise or any other matter. We can take two things from this: firstly, that South Australian wind farms are successfully operating within the framework set down in the existing guidelines and secondly, that this framework is adequately protecting the amenity of residents living around them.
The AWA has many members throughout the country who host wind farms on their properties and live short distances, sometimes only a few hundred metres, away from multiple turbines. Their experience supports this record and can be summed up by saying that while they can hear the turbines outside and sometimes even inside their homes, the noise they can hear doesn’t trouble them.
While there has been significant public correspondence in relation to the proposed Crystal Brook Energy Park, especially in regard to noise, the concerns expressed in much of this correspondence are not warranted when you look at the successful record of South Australian wind farms. As the draft guidelines state: “noise criteria recommended in the guidelines are among the strictest in the world.“ (p4). This should give the Authority pause when considering introducing new provisions or strengthening existing provisions in a framework that has already demonstrating itself as effective and robust.
2.6 Note on infrasound and low frequency noise
We welcome the Authority’s clear guidance on low frequency noise and infrasound outlined in section 2.6 and expanded on in section 4.7. The EPA’s 2013 study comparing infrasound from wind farms with infrasound found in other environments demonstrated clearly that while wind turbines generated low frequency noise it was at levels that were common in many other safe living and working environments and did not pose any danger to human health. This clarification in the guidelines will be important as long as some pockets of public discussion continue to posit the unproven idea that infrasound from wind farms can be a danger to human health.
4.6 Tonality, 4.7 Annoying Characteristics
The guidelines specify a 5dB(A) penalty where tonality is shown to be a characteristic of wind farms noise and is audible at a relevant receiver, taking into account the influence of the background.
Similarly Section 4.7, stipulates that “annoying characteristics that are not fundamental to a typical well-maintained wind farm must be rectified.”
These are both reasonable measures that ensure wind farm machinery is kept in proper working order to minimise output of tonal and other noise and as such we support their continued presence in the guidelines.
Flinders University paper on Amplitude Modulation (AM)
We note, however, a recently published paper by Hansen et al, “Prevalence of wind farm amplitude modulation at long-range residential locations”, which posits high levels of ‘tonal amplitude modulation’ around a single wind farm. While the Authority may be urged to alter these guidelines to respond to the paper, we would argue that it contains a number of shortcomings that raise serious questions about its reliability and should not be considered in the Authority’s review of these guidelines.
The paper takes a method developed by the Institute of Acoustics in the UK (IOA) to detect and classify AM and modifies it. The modifications described by the paper effectively “lower the bar” on the classification of AM, resulting in seven times the number of noise samples being classified as AM.
Of the samples classified as AM in the paper, 18% do not contain AM in comparison with 1% for the standard IOA method. The modifications have resulted in it being an unreliable method of detecting AM.
The methodology in the paper has not been devised based on listening tests, which would have enabled the audibility and severity of the AM to be tested against the methodology. Rather the effectiveness of the methodology is assessed against a pattern on a graph. It is not clear how this pattern relates to audibility or severity of the AM, particularly given that the levels of noise in many of the samples are either just audible or below the threshold of perception to humans. Notwithstanding the lack of listening tests, the paper uses emotive language such as “reliably detect the most annoying features of AM when AM is present”, when it is not known if a particular AM scenario is annoying or indeed audible.
The paper’s reliance on a theoretical model rather than listening tests is pertinent to this review as sections 4.6 - 4.8 of the guidelines all stipulate audibility at the receiver, which has not been demonstrated by the paper.
The paper is a study of one particular turbine model at one wind farm, which began construction in 2008. The technology of current turbine models has changed since this wind farm was constructed and therefore the findings of the paper cannot be applied in a blanket nature to other wind farms or to proposed wind farms.
Finally, the paper shows that with the wind farm not operating (0% power) an average modulation depth of approximately 7.0 is recorded. With the wind farm operating, a marginal increase in the average modulation depth to 7.8 is recorded. This result either demonstrates that the modulation associated with the turbines is not significant or that the methodology cannot be relied upon.
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