| |||
| |||
|
Introduction
What sounds do wind turbines make?
The sounds that I have heard have been:When close:
- A 'swish, swish' as the turbine blades pass by;
- A quieter sound from the gearbox (if one is present, not all turbines have a gearbox);
- The sound of cooling fans in the electrical equipment at the base of the turbine if there is a particularly low wind or no wind.
- A quiet 'whirring' sound when machinery in the turbine nacelle turns the turbine head to face the changing direction of the wind.
- A very quiet 'roar' or continual 'swoosh' from the combined sounds of a number of turbines. This will probably only be audible at all in low to moderate winds; if there is a high wind the sound of the wind in nearby vegetation will most likely drown-out the turbines sounds. Noise from any road traffic closer than the turbines will also drown-out turbine sounds.
How loud is a wind turbine?
If you are on a country road, there is a light breeze and there are wind turbines two kilometres away, you will probably be just able to hear them. If there is a car traveling on the road within one or two kilometres you probably won't hear the turbines because of the noise from the car; cars make more noise than wind turbines. If there is a strong breeze then you probably won't hear the turbines from a kilometre or more because of the noise the wind is making in nearby trees or shrubs. When I visited a wind farm during a strong gale I could not hear the turbines until I came within a couple of hundred metres.Wind turbines are not loud in the sense that pneumatic drills and jet engines are loud. Sound levels from turbines are typically no more than about 55 dB (A) when measured at a distance of about 100 m.
Sound levels always decline with distance; the rate of decline (with some exceptions) follows the inverse-square-law – twice the distance a quarter the sound, three times the distance a ninth the sound, etc.
The level of background noise at distances of a kilometre or more from wind turbines makes measuring the effect of sound from wind turbines on people at such distances complicated.
A few wind turbine opponents have claimed noise problems at distances as great as 5km or even more. Attenuation combined with the inverse-square-law show such claims to be quite ridiculous.
From my own experience I cannot imagine how the sound from a wind turbine could keep anyone awake at night and a report by Health Canada (the government department that is involved in health in Canada) indicates that loss of sleep due to wind turbine noise is a negligible problem. A strong antipathy to wind turbines is linked with annoyance from the sound.
In a paper titled Wind Turbine Noise, Infrasound and Noise Perception by Anthony L. Rogers, Ph.D., Renewable Energy Research Laboratory University of Massachusetts at Amherst USA, 2006/01/18, Rogers stated that as a rule of thumb, three times blade tip height from a turbine to a residence gives acceptable noise levels. I believe that this rule is used in Denmark, where there seem to be relatively few complaints about turbine noise and claims of health problems from turbines are practically unknown.
The Guardian carried an interesting article by Calla Wahlquist on 2015/06/26 about the local people's views on the 111-turbine Collgar Wind Farm in the Western Australian Wheatbelt. Two of the local farmers said that, while the nearest turbine was only a kilometre away, they could not hear it from inside the house and only occasionally from outside.
Also see, on this page,
Turbine sound compared to distant thunder.
Wikipedia states the following:
"Modern large turbines have low sound levels at ground level. For example, in December 2006, a Texas jury denied a noise pollution suit against FPL Energy, after the company demonstrated that noise readings were not excessive. The highest reading was 44 decibels, which was characterised as about the same level as a 10 mile/hour (16 km/hr) wind."The sound level perceived at distance from a turbine can depend on thermal layering in the air. A temperature inversion (a layer of cold air at low altitude, as often occurs at night) can cause sound to curve down toward the earth, resulting in the sound levels at a distance being higher than they would otherwise be.
|
Noise reduction: serrated trailing edges
Wind turbine manufacturers are continually researching methods of minimising should levels.A number of wind turbine researchers and manufacturers have found that serrated or combed trailing edges on wind turbine blades significantly lowers the sound level.
Greensolver, 2017/08/31, provided a useful discussion of serrations and their impact on turbine noise. It tells how serrated trailing edges on wind turbines not only reduce sound levels, they also change the quality of the sound; increasing higher frequencies relatively to lower frequencies. As mentioned elsewhere on this page, higher frequency sounds are more quickly attenuated with distance.
I have noticed that the serrated trailing edges were used on the Siemens turbines installed at
Snowtown Stage 2 wind farm in South Australia's Mid North.
|
|
|
Turbines and motor vehicles; the paradox
The number of passenger motor vehicles in the world was estimated to reach a billion in 2010; it has increased since. The number of utility-scale wind turbines in 2018 was about 325,000 (calculated from 651 GW of total wind power – Wikipedia – and an average of 2 MW per turbine).So there are about 3000 times as many motor vehicles as wind turbines. As mentioned below cars are noisier than wind turbines; if there is a car travelling on a road closer to you than a turbine you probably will not hear the turbine for the vehicle noise. (And, of course, trucks are much noisier than cars.)
|
The noise from wind turbines is minimised by the manufacturers. The noise from many motor vehicles is intentionally increased by modifications to their exhaust systems.
Yet society seems to accept motor vehicle noise while many wind power opponents loudly complain about the noise from wind turbines.
It makes no sense.
|
|
|
Infrasound: low frequency noise
Infrasound is sound of such a low frequency as to normally be inaudible to humans. There have been claims that infrasound (not just from wind turbines) has caused health problems, but this seems to be controversial. (I have written more on infrasound on my page about wind power and health.)The South Australian Environmental Protection Agency (EPA) produced a report titled "Infrasound levels near windfarms and in other environments" in January 2013. Extracts from the Executive Summary:
- "Infrasound levels at houses adjacent to wind farms ... are no higher than those at houses located a considerable distance from wind farms."
- "... there did not appear to be any noticeable contribution from the wind farm to the G-weighted infrasound level ..."
The Association of Australian Acoustical Consultants produced a Position Statement on Wind Farms (available from their downloads page). Among other things it stated that "investigations conclude that infrasound levels adjacent to wind farms are below the threshold of perception and below currently accepted limits set for infrasound".
|
An Australian Senate Committee, looking into alleged health effects from wind turbines, concluded the following in November 2012:
"The committee concludes that, while it is possible that the human body may detect infrasound in several ways, there is no evidence to suggest that inaudible infrasound (either from wind turbines or other sources) is creating health problems. In contrast, there is an established literature confirming the existence of psychogenic, or nocebo, effects in general, and at least one study suggesting they may be responsible for symptoms in some wind turbine cases."
| ||||
|
|
|
Geoff Leventhall on infrasound
Infrasound from Wind Turbines – Fact, Fiction or Deception; Geoff Leventhall. Published in Canadian Acoustics, Vol. 34 No.2 (2006). I can't do justice to this paper here, but will include a couple of points.In the abstract Leventhal wrote: "The perception of infrasound occcurs at levels higher than the levels produced by wind turbines and there is now agreement amongst acousticians that infrasound from wind turbines is not a problem."
Leventhal said that older down-wind turbines (those in which the blades are on the down-wind side of the tower) did sometimes cause vibrations in lightweight buildings nearby, but that "Modern up-wind turbines produce pulses which also analyse as infrasound, but at low levels, typically 50 to 70dB, well below the hearing threshold. Infrasound can be neglected in the assessment of the noise of modern wind turbines".
Peter Seligman on infrasound
Professor Peter Seligman is a biomedical and acoustic engineer who directed the development of seven generations of sound processor for the Cochlear Implant. In a personal communication which was a revision of his submission to the Senate inquiry into the 'Social and economic impact of rural wind farms' (No. 353) he stated that:"... the hearing and vestibular systems are subjected to very high levels of body generated noise. These include, walking, breathing, heartbeat, chewing and head movement. Body noises generated in this way were a problem in the Cochlear Ltd project to develop a fully implantable cochlear implant. In this case the microphone was implanted subcutaneously behind the ear. The level of infrasound picked up from the body by this microphone was a major problem and far exceeded all sound from external sources. In fact turning the head or chewing were some ten times louder than the external sounds we were trying to pick up.
So it is being held that levels that cannot be measured and cannot be heard, are problematic. In contrast, everybody is subjected to far higher internally self-generated natural infrasound levels which clearly, are not a problem. Typically, walking subjects the body to accelerations of about 1 g, at a frequency of about 2 steps per second, ie. 2 Hz. Translated into sound pressure, this acceleration is subjecting the body to infrasound at about 196 dB."
Research on infrasound by Associate Professor Con Doolan; 2013/02/06Associate Professor Con Doolan gave a presentation to a meeting of wind farm opponents, the Waterloo Concerned Citizens Group. The meeting was not advertised to the general public. (Professor Doolan had earlier told me by email that he would keep me informed on the progress of his research. He has given me nothing and did not inform me about the meeting.)For a scientist, attached to a major Australian university (Uni. of Adelaide), who one would hope was independent, unbiased and objective, to release his findings only to a group that is on one side of the controversy over wind farm noise, before publishing, and not giving supporters of wind power a chance to attend is questionable ethical behaviour. I have emailed Professor Doolan on this point (2013/02/06). It seems that Professor Doolan did not make any very specific statements about the noise levels from the wind farm. He is reported as saying: "further research would need to be undertaken to determine whether or not the noise experienced by residents was a result of the wind turbines, and to do this researchers would need the cooperation of the wind farm operator, Energy Australia." Professor Doolan said that Energy Australia (EA) had declined to cooperate with his research. I put this to Steve Brown of EA and was told that the reasons for this were that "EA had problems with Doolan's methodology" and the cooperation that Doolan was wanting involved economic loss of production to the wind farm. As of 2013/03/31 I had not received a response from Professor Doolan. |
|
|
Complaints against wind farms
Some people, often those who have had nothing to do with wind farms but have heard that a wind farm is proposed nearby, complain about wind turbine noise, in fact a wind turbine makes far less noise than a car.
The
Wind Farm Commissioner, running an office set up specifically to look into complaints about wind farms, has only
received a total of about 163 complaints from the whole of Australia, on all matters, not just noise, in two and a half years (October 2015 to May 2018); further, some 145 of the complaints have been resolved.
Annoying sounds
| ||
|
Wind turbine sounds might affect some people in the same way as does a neighbour's 'music'. Some sounds are more annoying than others and different people can react very differently to the same sounds. The perception and the attitude of the hearer are important. There is evidence that wind turbine noise annoys some people sufficiently to disturb their sleep, with consequent health effects. This may occur at distances of a kilometre or more, while others can sleep peacefully right under wind turbines.
Some sounds can be restful; most people would say that the sound of surf is pleasant. It seems that a sound that varies in a random way might be more easily tolerated than one that varies systematically; even traffic noise, though unpleasant, is tolerated by most people.
Restful sounds
The 'swoosh, swoosh, swoosh' of wind turbines is similar to the sound of surf. I find it pleasant and restful."Noise absolutely horrible"
Mr Bill Quinn, who appealed against one of the South Australian Hallett wind farms was quoted in the Flinders News (Port Pirie, 2011/11/23) as saying that "The noise coming from Hallett #2 [wind farm] was absolutely horrible." He lives three kilometres from the wind farm, but his mother lives two kilometres from some of the turbines. Mr Quinn said "Some nights [his mother] has to turn the ceiling fan on to drown out the noise".If the wind turbine noise could be drowned out by a ceiling fan, which in my experience are very quiet, it could not have been loud.
Erroneous readings
I have heard it claimed that sound levels of up to 100 dB have been measured 3 km from wind turbines. Such readings can only be explained as being due to someone not familiar with sound meters allowing the wind to blow over the microphone.
|
Room nodes
I have received an email from Keith Taylor (2012/06/13) regarding 'nodes' or points where sound peaks within a room. Keith pointed out that sounds coming from outside a room can be amplified, to a limited extent, within the room by the natural resonances due to the acoustical properties of the room. He suggested that sound levels can be particularly high at certain points within a room (therefore, if one is annoyed by turbine noises, these would be places where one should not have one's bed, for example).On 2013/07/19 I received an email from John Simpson, who, among other things, has been involved in technical sound recording for major movies. John wrote the following:
"I work in sound as a profession, and the comment by one person [Keith Taylor, above] on room nodes is very correct. I work in a sound proof room, even with 3 levels of sound proofing I will still hear a truck low end rumble from over 1.5 km away inside the room. Yet if I go outside the room it's hardly audible. This is because the sound proofing cuts out all frequencies above 100HZ it [is] very hard and expensive to get rid of lower frequencies. So all I hear in there is 100HZ and below making it very easy to hear these low freq sounds. Also you do get spots in a room where the freq is more predominant, so I can believe that a normally quite home that's over a KM away could have spots in the house where 100hz and below will seem quite loud, and [a] position change of just 1 meter in some rooms can go from no sound to quiet loud, especially as the surrounds in these places are normally quiet, as there is little other noise to drown out the turbine noise.
I believe this can be fixed for rooms in the home, there are various methods using active noise cancellation that may work. It would be interesting to experiment with this to see how much it can help."
This factor seems to have received little attention in the discussions around wind turbine noise and annoyance. I suspect it deserves more.
Turbine screech
At Cape Bridgewater and Hepburn there has been a problem with a 'screech' produced by a particular series of REpower wind turbine.Pacific Hydro (Cape Bridgewater) and Hepburn Wind have been working with REpower to try and get the problem fixed. It seems that the noise comes from the yaw system of the turbine; that is the machinery that turns the whole head of the turbine into the wind. The sound only occurs when the turbine is yawing. It is most noticeable when the wind is very light; less than 3 metres per second.
A wind power opponent has made a video clip of the sound on UTube. Note that while the sound as recorded in the video would be annoying, it is only a little above the level of background sounds.
The house involved is about 650m from a turbine. There are few houses in Australia that close to wind turbines. High pitched sounds such as this are attenuated quickly with increasing distance.
I find it interesting that while there have been many complaints from wind power opponents about how much noise wind turbines make, this is the only recording that I have come across of a sound that could be truly annoying.
|
|
Some noise levels compared
| Source/Activity | Indicative noise level dB (A) |
|---|---|
| Threshold of hearing | |
| Rural night-time background | |
| Quite bedroom | |
| Wind farm at 350m | |
| Busy road at 5km | |
| Car at 65km/hr at 100m | |
| Busy general office | |
| Conversation | |
| Truck at 50km/hr at 100m | |
| Inside a typical shopping center or restauant * |
|
| Inside modern car at around 90km/hr * | |
| Passenger cabin of jet aircraft * | |
| City traffic | |
| Pneumatic drill at 7m | |
| Jet aircraft at 250m | |
| Threshold of pain | |
Noise, or vibration, sources other than wind turbines
It is not unusual for people to be annoyed by noise or other vibrations and blame wind turbines, when some other source is the true cause.Much publicity is given to claimed noise problems from wind farms, while far less is given to noise from industrial sources such as mining, earth moving operations and low-flying aircraft and people can jump to unjustified conclusions when annoyed by an unfamiliar noise.
|
|
|
My own experience, research and opinion on wind turbine noise
|
Turbines are audible from distances as great as 2 km only in ideal conditions; when there is very little wind where the listener is, but sufficient wind where the turbines are on a ridge-top to power them. If there is a car on a road within about 2 km you will not hear the turbines because of the noise from the car.
I have visited many wind farms in Australia; all of those that were in SA and Victoria up to April 2009, and several in WA. No matter what the strength of the wind, one has no trouble conducting a normal conversation immediately beneath a modern utility scale wind turbine (for example, greater than 1 megawatt). The sound can vary from minute to minute, depending on the direction of the wind in particular; it seems that a greater level of noise can result from turbulence when air flows over a turbine blade at some angle other than the optimal.
|
|
I have camped overnight beneath the turbines of
Starfish Hill
(1.5 MW turbines),
Clements
Gap (2.1 MW turbines),
Waterloo
(3 MW turbines) and
North Brown Hill
(2.1 MW turbines) wind farms and had no problem at all getting
a good
night's sleep; I found the sound of the turbines, if anything, to be
relaxing.
(Also see
A good night's sleep at Waterloo in the section
'People driven from their homes by wind turbines?')
I recognise that this is
subjective
and that the experience of others may be different.
A caravan park within 850m of a wind farm
|
Another visit, April 2019
Denece, our dog and I stayed another three nights at the Toora Tourist Park in 2019, this time in a tent-trailer. Again we noticed the sound of the turbines at times, but did not find it at all annoying.Wiki Camps is an iPhone app that allows people to post comments on the camping grounds at which they stay. In all of the 106 comments posted about the Toora Tourist Park on Wiki Camps, from November 2012 to March 2019, there was not one complaint about turbine noise. There was one complaint about noisy cows, two about road noise, one about noisy drunks, one about fishermen chatting into the early morning, and one mention of a turbine being 'audible but not a problem'. There were many other complaints about matters not relating to noise or the wind turbines.
I have mentioned elsewhere about how dishonest the more vocal wind farm opponents are, so if you should look at the Wiki Camps entry for Toora Tourist Park after April 2019 don't be surprised to see complaints about noise from the wind farm – I would not be at all surprised if some of the opponents placed bogus postings in response to this observation.
Someone who lives near a wind farm
Anita Butcher lives in Mount Bryan 3km from the Hallett Hill Wind Farm and was a competitor for Youth of the Year in early 2013. As a part of the selection process for Youth of the Year competitors gave a speech on a subject of their own choice. Ms Butcher chose wind farms. She said: "I can honestly say that I have hardly heard a noise coming from the wind turbines."
|
|
More on my first-hand experience with wind turbine sound
I have also slept in an unoccupied house about 500m from the wind turbines at Leonards Hill. On these occasions I could not hear the turbines indoors at all.
|
I have taken sound level readings at Clements Gap Wind Farm (2.1 MW turbines) on several occasions; I recorded a maximum of 54 or 55 dB(A) at a distance of around 100 m from a turbine and the same immediately beneath a turbine. The sound levels at distances of 300-500 m were in the 40s, and at one or two kilometres, while the turbines were audible, my meter did not register a reading (it has a minimum of 40 dB). On all these occasions the breeze varied between light and strong (only once, when there was such a strong wind that some of the turbines had cut out, did I measure sound levels greater than 55 dB 100m from a turbine, on this occasion the sound level varied between 60 and 80 dB).
On a visit to Wattle Point Wind Farm, where 55 (1.65 MW) turbines are arranged in a grid with several public roads passing between the turbines, I recorded a maximum of 47 dB(A) among the turbines. I also noted that a car traveling at an estimated 60 km/hr 400 m from me was much noisier than the turbines that surrounded me.
The Hallett Hill Wind Farm (2.1 MW turbines) has been involved in controversy, some of which involved alleged noise problems. On a visit in May 2011, while all the turbines were turning, my sound meter did not register a reading (it starts at 40 dB) at any of five points on the public roads that go closest to the turbines. The turbines were inaudible to me at the township of Mount Bryan, at a distance of 3.8 km from the nearest turbines.
My impression is that the sound of turbines at 1000m would be less, less constant, and much less annoying than traffic noise anywhere in a large city. I'd prefer the sound of wind turbines at 1000m to the noise of a neighbour's kid riding a trail bike, or a quad bike being used to spray a neighbouring vineyard, or bird scaring guns in neighbouring vineyards; all sounds that I hear periodically and are small annoyances.
I am inclined to think that in a country like Australia, with no shortage of good sites for wind farming, no wind turbine should be built within one kilometre of a home without the informed consent of the owner. To build turbines less than one kilometre from a home would be to risk making the lives of the people in that home less pleasant. On the other hand, a distance of 2km, as has been adopted in NSW and Victoria, is quite unnecessary and would only be enforced by a government that is ignorant of the facts or biased against renewable energy. Ideally, the distance between turbines and houses should be set according to sound levels.
Claims of ill-health due to turbines are highly questionable and it is very
difficult to see why wind turbine noise should be any different from other
environmental noise such as that due to traffic or even wind in trees or
wires.
I've never been invited to a home to listen to turbine noise
I have been writing these pages since February 2004. Since Ms Sarah Laurie started her campaign trying to convince people that wind turbines cause illness in 2010 there have been quite a few people complaining of excessive noise from wind turbines in my region, Mid-North South Australia. (Around this time more than 40% of Australia's wind power was in SA and well over half of SA's wind power was in this region.) Curiously, no one has ever invited me to visit their house and hear the noise for myself.Some years ago Ms Sarah Laurie arranged with a person who lives about 3km from turbines and complained of excessive noise to 'phone me when the noise was particularly loud so that I could go and hear it. The telephone call never came.
Some people who are opposed to the Waterloo Wind Farm have claimed that the noise in the very small township of Waterloo is so bad that several houses have been abandoned. I have visited Waterloo at least eight times, have got out of my car and listened. I have never yet heard the turbines (3km from the town) from the town, even though on several of those occasions the conditions were excellent, with no wind in the town, but a good breeze on the ridge and the turbines operating.
I find it difficult to conclude from this anything other than that the noise cannot really be as bad as these people claim it to be.
|
|
Some noise claims with which I have had personal involvement
These claims are so contrary to my personal experience with the sound levels from wind farms that I find it very difficult to understand how the people involved can be so badly mistaken. I accept that these people believe what they have said to be true, but I cannot understand it except to put it down to a gross form of self-deception. That humans can deceive themselves to this extent has been an eye-opener to me.
Can it be anything other than self-deception?Apart from the statements discussed below, I've come across a number of other claims about the wind turbine noise in situations that are quite unbelievable.On another page I have recorded statements made on a talk-back ABC radio program hosted by Matthew Abraham and David Bevan:
In the introduction to the book Wind Farm Noise: Measurement, Assessment and Control by Colin Hansen, Con Doolan and Kristy Hansen, is the statement that "the character and level of wind farm noise is a problem for a significant number of people, even those who reside at distances of 3 km or more from the nearest turbine." As I have mentioned elsewhere, wind turbines are very rarely audible from distances greater than 2.5 km. (I have no doubt that acoustic equipment can detect sound (and other vibrations) from wind turbines at distances greater than 3 km, just as seismometers can detect small earthquakes on the far side of the Earth.) On the other hand, when people can hear nearby turbines, there often seems to be little annoyance.I suspect that the Toora Tourist Park would be the closest camping/caravan park to a wind farm in Australia; it is only 850 metres from the nearest turbine.Wiki Camps is an iPhone app that allows people to post comments on the camping grounds at which they stay. In all of the 106 comments posted about the Toora Tourist Park on Wiki Camps, from November 2012 to March 2019, there was not one complaint about turbine noise. There was one complaint about noisy cows, two about road noise, one about noisy drunks, one about fishermen chatting into the early morning, and one mention of a turbine being 'audible but not a problem'. There were many other complaints about matters not relating to noise or the wind turbines. |
| ||
|
Pharmacist
George Papadopolous of Yass has claimed that 40 wind turbines "35km away at times has turned the quiet rural area of the northern hills of Yass into a rumbling mess." I have corresponded with George several times. He seems quite convinced that he is right, I accept that he probably believes what he says to be true, even though it does not stand up to any sort of reasonable examination.Farmer
A farmer who lives about three kilometres from the Hallett Hill Wind Farm complained about loud noise at times. Ms Sarah Laurie arranged with him to inform me when the sound was particularly loud so that I could go and hear it. The phone call never came.Mayor Peter Mattey, Goyder Council
Peter Mattey, Mayor of Goyder council gave a verbal submission to the Legislative Council Select Committee on Wind Farm Developments in South Australia at Clare Country Club on 2013/07/17. He said:"... but I had the misfortune to get a flat tyre one day about two and a half kilometres from out in front of one of these whole rows of turbines. When I got out to change the tyre I could hardly hear myself think. It was just horrendous."
While I've visited almost all the wind farms in South Australia and Victoria and a number in Western Australia I have never come across loud sound at any distance at all; not even right underneath wind turbines.
Following a number of attempts to contact him, by telephone, email, and post, Mayor Mattey 'phoned me on 2013/10/29. After discussing the matter with him I accept that he was speaking in good faith in as much as he believed what he said to be true. He gave me clear directions to the location of the road, but was less clear on the exact place he had the flat tyre. He said in his submission, "I was on a bit of high ground out in front of the turbines, not as high as they were, but on high ground." He did not know the name of the road, but from his description it was Parker Road.
My wife and I visited the place on 2013/11/03. We parked our car at South Latitude 33.4197°, East Longitude 138.7406°, which seemed likely to be about where Mayor Mattey had his flat tyre, and walked one and a half kilometres along the road toward the row of wind turbines on the Brown Hill Range, finishing at Latitude 33.4205°, Longitude 138.7249° at a point on the ridge on the line of the turbines. There was a moderate breeze and the wind turbines were operating.
Where we parked the car we could hear the turbines; I would describe the sound level as a bit more than barely audible. As we approached the line of turbines the sound level increased until on the ridge I recorded around 60dB, a level at which the turbines were plainly audible, but far from unpleasantly loud. As would reasonably be expected, the sound had steadily increased as we approached the line of turbines.
We did not experience anything remotely like what Mayor Mattey had described. What he heard is a complete mystery to me. It could not have been the wind in nearby trees or shrubs, the area is completely devoid of vegetation other than grasses etcetera.
|
|
|
Study of wind turbine setbacks internationally
|
The 2km setbacks from homes favoured by the Liberal Party in South Australia and Victoria (and the 5km from towns legislated in Victoria) is obviously very much out of step with international norms. This is, however, in line with the Australian Liberal Party's favouring of coal ahead of renewables. Here again, the Liberals are very out of step with the rest of the world.
|
|
|
South Australian EPA research
The South Australian Environmental Protection Agency (EPA) produced a report titled "Infrasound levels near windfarms and in other environments" in January 2013. A significant conclusion of the research was given in the 'Summary of results':"This study concludes that the level of infrasound at houses near the wind turbines assessed is no greater than that experienced in other urban and rural environments, and that the contribution of wind turbines to the measured infrasound levels is insignificant in comparison with the background level of infrasound in the environment."While this research was not conducted at Waterloo, it is very relevant to the allegations that have been made about this wind farm.
Major EPA study at Waterloo
On 2013/11/26 the South Australian Environment Protection Agency (EPA) reported on a noise study they had done over a ten-week period from April to June in 2013. In this study the EPA arranged with a number of residents who lived near the wind farm to keep diaries in which they recorded their level of annoyance from the wind farm.Because of the significant controversy around the Waterloo Wind Farm I will copy the summary of the findings of the EPA study here:
- 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; however, in many cases, the EPA was unable to determine that described events could be attributed 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.
|
|
Health Canada's report
Wind turbines and sleep
Health Canada, November 2014; Wind Turbine Noise and Health Study: Summary of Results – health and quality of life were found to be unaffected by nearby wind turbines, some annoyance was found.With particular regard to the present subject, Health Canada reported that:
"The following were not found to be associated with WTN exposure:In other words, there was no link found between sleep disorders and actual levels of wind turbine noise.While some individuals reported some of the health conditions above, the prevalence was not found to change in relation to WTN levels.
- self-reported sleep (e.g., general disturbance, use of sleep medication, diagnosed sleep disorders);
- self-reported illnesses (e.g., dizziness, tinnitus, prevalence of frequent migraines and headaches) and chronic health conditions (e.g., heart disease, high blood pressure and diabetes); and
- self-reported perceived stress and quality of life.
Results of self-reported measures of sleep, that relate to aspects including, but not limited to general disturbance, use of sleep medication, diagnosed sleep disorders and scores on the PSQI [Pittsburgh Sleep Quality Index], did not support an association between sleep quality and WTN [wind turbine noise] levels."
|
|
|
Wind turbine noise compared to distant thunder
|
If the reader has ever heard thunder caused by a nearby lightning strike and has also heard the sound of a nearby wind turbine he or she will know that there is no real comparison. The sound from a nearby lightning stroke can be literally deafening, while one can carry on a conversation beneath an operating wind turbine without raising one's voice. Under How loud is a wind turbine?, on this page, there is a figure showing that the sound of a wind turbine from 100m away is about 50dB. A 50dB sound has 1/10,000,000 of the energy of a 120dB sound.
Yet, while thunder can only be heard from 16km under good conditions some people will claim that wind turbines can be heard from similar, or even greater, distances.
In my experience, one can hear turbines at 2 km, perhaps two and a half kilometres in ideal circumstances, but very rarely hear a wind turbine from as far as 3km away. Try it yourself.
|
|
|
Wind Farm sleep study, Flinders University
I was one of the participants in the Wind Farm sleep study conducted by the Flinders University. My involvement started about 2020/03/02, my wife and I were fully involved at the Sir Mark Oliphant Building of Flinders University every night from 2020/03/10 to 2020/03/17 and as of the time of writing (March 18th) we still have a commitment to maintain a 'sleep diary'.I have written a page about my involvement and observations on the sleep study.
Sara Garcia wrote a piece on the study for the ABC on 2018/01/25.
|
|
|
Links – Wind Turbine Noise
To be fully acceptable to scientists research generally has to be published in reputable peer-reviewed journals.- Council of Canadian Academies, April 2015; Understanding the Evidence: Wind Turbine Noise – Found evidence of a causal relationship between exposure to wind turbine noise and annoyance and possibly sleep disturbance. Insufficient evidence of any other link with health.
- Health Canada, November 2014;
Wind Turbine Noise and Health Study:
Summary of Results – health, sleep and quality of life were found
to be unaffected by nearby wind turbines, some annoyance was found.
(See note on this page.)
Professor Simon Chapman's summary of the findings in the Health Canada report. - The South Australian Environmental Protection Agency (EPA) produced a report titled "Infrasound levels near windfarms and in other environments" in January 2013. The investigation found no higher infrasound levels near wind farms than elsewhere.
- On 2013/11/26 the SA EPA reported on a noise study they had done over a ten-week period from April to June in 2013. In this study the EPA arranged with a number of residents who lived near the wind farm to keep diaries in which they recorded their level of annoyance from the wind farm. A summary of the EPA's findings can be read on the EPA site.
- The Victorian (Australia) Department of Health produced a study titled Wind farms, sound and health and concluded: "There is no evidence that sound which is at inaudible levels can have a physiological effect on the human body. This is the case for sound at any frequency, including infrasound."
- The Association of Australian Acoustical Consultants produced a Position Statement on Wind Farms (no longer available on the Net). Among other things it stated that "investigations conclude that infrasound levels adjacent to wind farms are below the threshold of perception and below currently accepted limits set for infrasound".
- The physics of sound: Uni. NSW has a fascinating site with lots of graphics and audio pieces on what sound is all about.
- Conference paper Outcome of systematic research on wind turbine noise in Japan by Hideki Tachibana, Professor Emeritus, University of Tokyo. Conclusions: "wind turbine noise is not a problem in the infrasound frequency region", but wind turbines in residential areas could produce enough audible noise as to be annoying, especially at night.
-
Effects of industrial wind turbine noise on sleep and health by Nissenbaum, Michael A.; Aramini, Jeffery J.; Hanning, Christopher D.; published in Noise and Health. The authors stated that study subjects living closer to wind turbines generally had poorer sleep than those living further away. (Also see the box on the right.)It should be said that there was a very large overlap in the responses of the participants in the Noise and Health study; many subjects living near wind farms had better sleep than many who lived further away. The study's statistical significance seems questionable. - Christopher Hanning, British Medical Journal, March 2012 (BMJ 2012;344:e1527). Hanning discussed turbine noise, sleep disturbance, and consequent health effects.
- Pedersen E, Waye KP, Perception and annoyance due to wind turbine noise–a dose-response relationship. Journal Acoustic Soc. Am. 2004. Science Watch rates Journal Acoustic Soc. Am. at an impact factor of 2.98 (2004-2008).
- "Responses of the ear to low frequency sounds, infrasound and wind turbines" Alec N. Salt, Timothy E. Hullar (Elsevier, Hearing Research (2010), doi: 10.1016/j.heares.2010.06.007). Elsevier claim an impact factor of 2.177 for the Hearing Research journal.
- Think Progress published an article titled Wind Turbines Are Quieter Than A Heart Beat, Acoustical Experts Find, 2013/09/24.
- An article on the European Wind Energy Association Blog, dated 2012/05/24 discusses a new study by the Bavarian Environment Agency in Germany. It concludes that wind farm infrasound is no health threat. It also mentions other studies that show the same thing.
- Prevalence of wind farm amplitude modulation at long-range residential locations; L. Hansen, Phuc Nguyen, Branko Zajamšek, Peter Catcheside, Colin H.Hansen (abstract, full text available online for Aus$91)
The Australian Wind Alliance' response to this study: Wind study full of holes
I believe that this study concerned Waterloo Wind Farm. My own experience with sound from this wind farm is very much at odds with the Hansen et.al. study.
Other links relating to wind power:
- Relating to wind power problems, alleged problems and objections;
- Relating to Wind power and health;
- General wind power links.