You being a man of science: Joshi on perception and wind farm sound

Published by Etwas Luft. View the original article.  

By Ketan Joshi,  Research and Communications Officer at Infigen Energy. These views are his own. 

On the night of May 28th, Greens MLC Mark Parnell pitched a tent directly underneath a wind turbine at Waterloo Wind Farm, and had a relatively peaceful night’s rest. Prior to his camping experience, Parnell was interviewed on ABC’s Breakfast Reloaded by Matthew Abraham and David Bevan:

Host: Mark Parnell, you being a man of science, why would you say that camping within 100 metres of the pole is going to give you an experience that people who live a kilometre away will experience?

The assertion that sound energy from a wind turbine will somehow be greater at a distance of one kilometre away and inside a house, compared to 100 metres away and inside a tent, is a good example of the homeopathic logic that characterises discourse around wind energy.

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The “Inverse Square Law”: As you move further away from a sound source, the noise level decreases by the square of the distance. Things get quieter as you move away from them, not louder.

Parnell tries (several times) during the interview to point out that Waterloo is comprised of more than one wind turbine, and consequently, he would have been at varying distances from several machines during his stay. His efforts were in vain. The hosts then interview a man named Bob, living 10 kilometres away from Waterloo Wind Farm:

Bob: I’ve been opposed to these things from way back. Anything of this scale, from an ecological point of view, is just wrong.

Bob tries diverting the topic away from noise and towards birds, and the host patiently tries to steer him back:

Host: If I could just ask you about the noise, what can you hear right now?

Bob: Well, it’s like an agitator sound. It appears….well it does appear like it is just in my head, because my partner can’t hear it but at times she can hear it, and I can’t…it’s a perplexing thing, because you get two people in a house and they hear it completely differently, we describe it differently…

The interview is hastily cut short, but not before Bob has inadvertently highlighted an important fact about perception – subjectivity plays a significant role in how we perceive sound.

Research has shown that attitudes towards wind farms is a reliable predictor of how one will react to them – in this case, Bob states explicitly that he’s always been ‘opposed to these things’, and then goes on to describe the tenuous sensation he attributes to the wind farm.

This effect is not bound by distance. The host also interviews Mary Morris, a motivated opponent of wind energy, living 17 kilometres from Waterloo. He brings up recent research, work he characterises as suggesting ‘wind turbine syndrome’ is ‘all in the mind’:

Mary Morris: It’s definitely not in the mind, and especially when you’ve got children who are affected, as I have, in the vicinity of the turbines when your child gets a headache and an earache and when you go away it stops, my child isn’t making that up.

17 kilometres is a fair distance. To put this in perspective, this is the same as living in Parramatta and being affected by traffic noise (which is significantly louder than a wind turbine – Edit: to clarify, at a distance of 350m) in the Sydney CBD, or arriving at Melbourne airport and being irritated by construction work in the Melbourne CBD. Even in a quiet environment, with little background noise, wind farm infrasound and low-frequency noise is extremely unlikely to be detectable at that distance.

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Wind farm noise modelling gives us a fairly accurate picture of acoustic emissions, but attitudinal factors can cause a wildly disparate community response

The radio piece seemed to summarise one enormously important point about wind energy – the sensation of hearing must always be interpreted by the machinery of perception inside our brain. We have to consider the role of attitude, anxiety and belief in the perception of sound, in conjunction with measurements and analysis. These factors might give us a better understanding of why perception seems to vary so wildly from measurements, engineering and science.

After the protestations of another parliamentary committee member, three MLCs and a Nine journalist stayed a night in an ‘abandoned’ house, a few kilometres from the wind farm. The outcome:

“Neighbours insist the sound and vibrating fury of the turbines seeps into your synapses, causing headaches and palpitations and destroying the sanctity of your nightly repose.  Personally, I couldn’t hear a thing above the snoring resonating from the rooms around me”

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