A substantial degree of technical incompetence – or intended to mislead the community

26th February 2013

From Steven E. Cooper, The Acoustic Group

PEER   REVIEW   COMMENTS

SOUTH  AUSTRALIAN  EPA  AND  RESONATE  ACOUSTICS

“INFRASOUND  LEVELS  NEAR  WINDFARMS  AND  IN  OTHER  ENVIRONMENTS”

Issued by the South Australian EPA, dated January 2013

Various wind developers and industry lobby groups both in Australia and around the world have been claiming that the recent report issued by the South Australian EPA and Resonate Acoustics is a scientifically valid document, that has confirmed infrasound associated with wind turbines is a non-event and persons raising such issues are simply scaremongering. A cursory examination of the document as set out below suggests a substantial degree of incompetence or alternatively, that it is a document intended to mislead the community.

The primary function of the document purports to indicate that the use of the dB(G) parameter is appropriate for accurate and complete measurement of infrasound. After selective testing of a number of sites, there is a claim that both rural and residential areas experienced dB(G) levels higher than that associated with wind turbines.

As wind farms are normally placed in rural areas, and similarly so are scattered individual turbines, then there is a fundamental problem with utilising noise criteria issued for suburban environments where such environments do not experience wind farm noise and vibration, and such environments are significantly different to the much quieter background soundscape experienced in rural areas.

The authors claim in Section 2.1 that the dB(G) parameter covers the majority of the infrasound frequency associated with wind turbines, and then immediately provides a graph of the G-Weighting filter obtained from the ISO Standard 7196.

Immediately following the first paragraph of Section 2.1 a Figure is provided showing the weighting characteristics of the G-filter, and follows the procedure in the ISO Standard of referencing the attenuation with respect to a level of 0 dB at 10 Hz. The filter shows that there is amplification above the region of 10 Hz to 25 Hz, with a maximum of +9dB at 20 Hz.

Between 1 Hz and 20 Hz the filter drops off at 12 dB per octave whilst below 1 Hz and above 20Hz the filter drops off at 24 dB per octave.

graph 1-page-001

At 6.3 Hz, being a typical lower limit of some sound level meters that can provide 1/3 octave band results, the dB(G) filter has a value of 8 dB below the reference level at 10 Hz. Similarly at a frequency of 1 Hz (that is typically near the blade pass frequency of modern day turbines) the filter exhibits a level of 43 dB below the 10 Hz 0 dB reference level.

Using dB level expressed in a Linear (Un-weighted) format, the frequency spectrum from modern day wind turbines is predominantly elevated in the 0.7 to 6 Hz region.   It is therefore apparent to those appropriately trained in acoustics that the dB(G) value does not cover the majority of the infrasound region generated by turbines.

For example, later in the report (Figure 29) there is a 1/3 octave band spectrum chart limited to the frequency range of 0.25 Hz to 20 Hz that is reproduced below.

Figure 29-page-001

Examination of the above chart clearly indicates a significant degree of energy in the lower portion of the infrasound band.   When it is superimposed with the dB(G) curve (Figure 2), it shows the claim as to the relevance of the dB(G) for infrasound noise from turbines to be incorrect.

The report goes to great lengths to discuss measurements conducted at various locations in office buildings and suburban environments, with suggestions of likely noise levels influencing the infrasound results that appear to be somewhat vague and non-specific. Persons experienced in conducting measurements in such environments will be well aware of the influence of air conditioning controlling the background levels (especially infrasound being associated with airflow).   Despite acknowledging one building having air conditioning, with the increase in levels that follows, the time period of office environment, the concept of air conditioning determining the environment at a number of locations appears to have been conveniently overlooked by the authors of the report.

Similarly in terms of infrasound in houses the report is not specific as to the source of the internal noise, or the influence of external noise or weather conditions at the time.

The report provides measurements for a dwelling in proximity to a wind farm and a second dwelling in proximity to another wind farm where it is purported that there were on/off tests (being a shutdown).

The report indicates wind that existed during a shutdown to give rise to various dB(G) levels but fails to indicate the direction of the wind. For the operation of the wind farm, the report fails to identify the relationship of the turbines to the receiver location for such wind variations, the relationship of the extent of the wind farm to the receiver locations, or the operating output of the turbines.

The dB(G) levels are presented in terms of L90, Leq and Lmax that appear to not quite cover the reported range of the levels shown on the dB(G) graphs, and therefore this leads to some confusion in seeking to verify the interpretation or conclusions concerning dB(G) that are provided by the authors.

A significant criticism in relation to the 1/3 octave band measurements, is that whilst conducting a 10 minute Leq assessment, the authors chose to utilise a time response of 10 second averaging, rather than fast response as required by their own documentation for compliance testing. Reliance on the 10 second average appears to be related to the low frequencies of concern without identifying the reduction in measured levels that would follow, when compared to the assessment procedure in their guideline. Clearly the use of a long averaging time reduces the impact of the fluctuations or modulation associated with the emission of low frequency in infrasound noise from turbines. This is important, because it provides a lower measured level that occurs and as such reduces the level that would be identifies as the peaks the ear “hears” rather than the “averages”.

It is also noted that the report does not address low frequency noise which one assumes would also have been obtained during such testing.  Low frequency noise has recently been shown by Professor Con Doolan to be directly associated with specific symptoms under the label of “annoyance” and the severity of those symptoms correlated precisely with the “dose” or SPL of sound energy present in those frequencies at the time.

Similarly in relation to 1/3 octave band material, levels are provided from 0.25 Hz to 20 Hz (purporting to have been obtained during a shutdown) indicate variations with wind strengths and  wind direction and there are a number of substantial holes in the data provided.

In all cases, the operational settings of the wind farms are not presented to indicate the power output of the wind farm, nor is the number of turbines on the wind farm that were operating prior to the shutdown and after the shutdown disclosed. Residents in South Australia are aware of the EPA and wind farm consultants undertaking “compliance tests” whilst the closest turbines are feathered or even stopped.

The report makes reference to measurements over a number of weeks and comparison of the average levels of the material provided, but the material as to weeks of testing is not provided, and this leads one to question the conclusions.

The report purports to identify that the natural environment for a house near a wind farm exhibits spectral peaks associated with the blade pass frequency and the first few harmonics even when the turbine is not operating, which seems to defy the laws of physics and measurements that have been conducted at various residential properties by consultants both in Australia and the United States. The fact that the authors of the report are claiming that there are noticeable spectral peaks at the typical blade pass frequency and multiple harmonics, even when the wind farm is shutdown, questions the validity of the report It may the case that not all turbines were shutdown as suggested in the report and that there may well have been turbines within 10km of the measurement site still operating, whose acoustic emissions were affecting these measurements.

Measurements of ambient noise in rural areas in the absence of turbines do not experience the spectral peaks at the blade pass frequency and multiple harmonics as suggested in the report. It may the case that not all turbines were shutdown as suggested in the report and that there may well have been turbines within 10km of the measurement site still operating.

It appears that the locations used for monitoring where the authors concluded that wind farm infrasound was less than for other locations, may be sites where complaints have been made in relation to the wind turbine noise that have still not been addressed by the South Australian EPA. Other locations in the area have been ignored despite the community having identified there have been hundreds of complaints to the EPA.

As both the EPA representative and the authors attributed to Resonate Acoustics are aware of the communities’ concerns and issues pertaining to modulation, tonality, audibility, sleep disturbance and adverse health impacts, then the conclusions of the report based on inaccurate technical information leads one to question the objectives of the study. It would appear that Resonate Acoustics are regularly employed by the wind industry. Documentation from the community questions both the independence and the conduct of the nominated EPA officer with respect to dealings with the community in relation to other wind farms.

Without the appropriate material as to various operating scenarios of wind farms, wind direction, wind speed, power output of the wind farm and identification of the nature of all turbines so operating, and without any independent verification of the testing and the results (as per the Wisconsin Shirley wind project Cooperative study involving Messrs Hessler, Walker, Rand and Dr Schomer) then little weight can be placed upon the conclusions or the validity of the report as to the facts of infrasound from large industrial wind turbines and their impact on health. On the contrary the contents of the report support the concerns raised by the community as to the conduct of both organisations (the EPA and acousticians who work as consultants to the wind industry) and clearly demonstrates the need for independent monitoring and observations to occur in the forthcoming Waterloo study involving the community and requires both outside and inside measurements.

I consider that as a minimum, the proposed EPA study at Waterloo in South Australia should incorporate full spectrum measurements similar to that provided in the Wisconsin study with both 1/3 octave and narrowband analysis incorporating simultaneous inside and outside measurements and incorporating on/off testing of the wind farm.

In addition to the provision of all the noise data it is also imperative that in conducting a proper and independent test that all of the material in relation to the operating parameters of the wind farm, prevailing weather conditions etc. be available to the review team (also including representatives on behalf of the community) so as to ensure that study is fully independent and not contaminated such as in the case of the recent report issued by the South Australian EPA and Resonate Acoustics.

The Acoustic Group Pty Ltd

sig-page-001

Steven E. Cooper

About stopthesethings

We are a group of citizens concerned about the rapid spread of industrial wind power generation installations across Australia.

Comments

  1. Reblogged this on Quixotes Last Stand.

  2. Mr. Cooper is a man of integrity and he has the best equipment to monitor noise levels from industrial wind turbines. He has monitored a house around 7 km from a WT complex and it showed there was noise levels from the turbines. With the wind industry making loads of money the Government should stop RECs and see what happens then. This renewable energy from wind turbines is nothing short of a money grab not a reliable industry with ‘gag’ clauses for hosts threatened with legal action if they say anything negative. People are now starting to wake up to the industry and its dirty tricks. They do not prove that wind turbines don’t cause noise or health issues but shoot arrows at their opponents. People are supposed to be affected by the ‘nocebo’ effect yet studies have shown that people with sleeplessness from noise suffer all sorts of ailments. A study released today here in Australia says people require 7-8 hours a night. Try sleeping with whooshing and thumping. The EPA report shows the dirty tactics the wind industry uses to ocntinue to reap millions of dollars as MP Alby Shultz says will amount to 1/2 a billion per annum in his electorate alone. There are forms of renewable energy worth pursuing but wind relies o backup 24/7 from coal or gas. How can that be renewable energy? When you read about the materials used to build WTs and the tonnes and tonnes of concrete used to support them causing more CO2 emissions you cannot call them ‘green’ energy.

  3. My compliments to Steven for his willingness to identify issues here that question the honesty and integrity of evaluation and reporting by the EPA. Manipulation of environmental sampling is a strategy the EPA and expert consultants intent on not disclosing health risk to workers and the public have used many times in the past. It has allowed the system to pretend that all that can be done is being done. The other direction has been that the EPA denies resource capacity to engage an evaluation issue. The science behind many environmental risk issues is very complex, even for noise, as Steven points to. On this basis the EPA should be knocking continually at the door of the Department of Health. That doesn’t happen often, but when it does, sadly appropriate expertise is not available there either. Again we are told there is no resource to evaluate the biological, physiological associations of environmental intrusion. Get out of the way is a line that has come from the EPA from a number of levels within the organisation. This fails to provide any answers or reduction of further harm in our community for the future. Our suggestion is that we have national authorities, from within enHealth, now the National Public Health Protection Committee, to take up the questions from the report undertaken on the Health effects of noise, other than hearing loss, reported in 2004; http://www.health.gov.au/internet/main/publishing.nsf/content/33165540CB3C78CBCA256F1900042E72/$File/env_noise.pdf . We have had nothing but promises from Government since, and then in Dec 2012, an unannounced halt to such review, to close the public out and save costs. Our call is to the National Minister for Health, Hon Tanya Plibersek MP, to reconsider this decision. While not associated with noise from turbines, Access Economics evaluated the cost of hearing loss and reported in 2006, that it was $11.75Billion annually, with a further $11.3Billion associated with health issues. 37% of this harms was conservatively estimated to be from uncontrolled noise; http://www.accesseconomics.com.au/publicationsreports/getreport.php?report=71&id=81
    Just how much economic harm has to happen for our politicians to act to see proper evaluation and account of health risks associated with noise? How much longer will the handballing and arranged evaluation by consultants and the EPA continue before there is some political challenge?

Trackbacks

  1. […] at 500m” furphy; producing completely bogus wind turbine noise “studies” (see our post here); and running pitches that listening to wind turbine noise is just like listening to waves lapping […]

  2. […] find out soon enough – crack operators, Steve Cooper and Prof Colin Hansen had that same place bristling with their state-of-the-art kit, at the same […]

  3. […] acoustic consultants have not done and will never do.  The low-frequency testing done by AGL used the same method discredited by Steve Cooper a while […]

  4. […] recently released a scathing critique of a report by the South Australian EPA and a company called Resonate Acoustics on infrasound at Waterloo wind […]

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