The Associate Director of Resonate Acoustics gave a presentation at Clean Energy Week 2013 last week, that I found pretty unnerving. If anti-wind lobby is right in their assertion that infrasound has an effect on human physiology at the low levels produced by wind turbines, then we're all going to have to consider some fairly drastic consequences.
|Click to embiggen|
Infrasound is sound below a frequency of twenty hertz. As you can see above, you can't hear it unless it's very, very loud. Human beings have been awash in low levels of infrasound for millions of years, and we still are. Resonate demonstrated this with some simple measurements:
|Something that may make robots slightly nervous.|
Yep, by simply walking around, you're exposing yourself to a higher amplitude of infrasound than you would if you were near inside a house near a wind farm (which, according to opponents of wind energy, is worse than sleeping directly underneath a turbine).
The average human walks around 56,327 kilometres in their lifetime. At an average walking speed of 4.51 km/h, we spend ~12,489 hours, during our lifetime, walking. Using an average of 2.3 km per day, yesterday, 22,320,000 Australians walked a cumulative ~51,256,468 kilometres. That's 1,279 trips around Earth.
Basically, it's a shitload of walking, all of which seems to occur without spawning the symptoms of 'Wind Turbine Syndrome'.
If that wasn't bad enough, the acousticians also placed their equipment in a car, and measured infrasound:
|Again, an issue not limited to humans.|
As you'd expect, the amplitude of infrasound you're exposed to whilst driving in a car is significantly higher than your exposure to infrasound near a wind farm. Interestingly, a car moving at 60 km/h with the rear windows down can actually produce audible infrasound, greater than 100 dB. The author of the presentation tells me that their work has been submitted for review.
So, next time you hear of anti-wind groups travelling to towns and attempting to create fear and uncertainty around renewable energy, based on the invisible threat of infrasound, think back to the last time you walked down the street. Did you experience any of the 216 symptoms attributed to exposure to low levels of infrasound? Probably not.