Wind Farm noise? 35-45 dB @ 350m, rural nightime background noise: 20-40 dB

[JohnWxy]

http://www.windri.org/survey/references/windenergynoise.pdf

Today, an operating wind farm at a distance of 750 to 1,000 feet is no noisier than a kitchen refrigerator or a moderately quiet room.

Source/Activity .................Indicative noise level dB (A)
Threshold of hearing ..........................0
Rural night-time background................ 20-40
Quiet bedroom................................... 35
Wind farm at 350m........................... 35-45
Car at 40mph at 100m........................ 55
Busy general office........................... 60
Truck at 30mph at 100m .................65
Pneumatic drill at 7m................. 95
Jet aircraft at 250m................. 105
Threshold of pain .................140


Source: The Scottish Office, Environment Department, Planning Advice Note, PAN 45, Annex A: Wind Power, A.27. Renewable Energy Technologies, August 1994. Cited in "Noise from Wind Turbines," British Wind Energy Association, http://www.britishwindenergy.co.uk/ref/noise.html .

[kristopher]

1. I clocked the spring frogs in my backyard at 87db last year.

It is the most godawful racket you've ever heard...

[NNadir]

3. Well one solution would be to grind all those frogs up. After that you can...

...write to all the people who complain about wind turbine noise in their backyard and tell them all about how stoooooopid they are for complaining, because the frogs you had to kill were louder.

Be sure to use a 240 ft grinder, like the ones we like to grind up whooping cranes with, since their calls are very loud. Say a frog grinder about this size:



Then tell them that another airhead "renewables will save us" advocate who, like you is unfamiliar with mathematics and the concept of logarithms (and consequently what a decibel is) says "shut your mouthes" you whiny people, wind power is going to save the world. I know because I read Mark Z. Jacobson's paper a brazillion times."

[Statistical]

2. Tell me you would want to live here?

http://www.youtube.com/watch?v=iyOImGHyJtQ&feature=related

[wtmusic]

4. The noise seems to be very dependent on the design

In some of the other youtube clips they're nearly silent.

The shadow flicker would drive me more than a little batty.

[Statistical]

5. I think long term the flicker effect is larger concern.

Reducing sound simply requires better engineering.
Also the sound energy is reduced at the square of the distance so tripling distance from turbine reduces the perceived sound energy by a factor of 9x.
Increasing setbacks, requiring more sound insulation, and better blade designs may be all that is required to resolve noise issue.

However if you have large moving object that blocks light and sun you will have flicker.
The flicker effect won't be reduced by distance. It is 100% up to the point where the shadow no longer falls on someones property.

Here is a video (about halfway through) showing flicker effect inside a house (1100 ft from turbine).
http://www.youtube.com/watch?v=MbIe0iUtelQ&feature=related

Computer models to simulate flicker effect based on GPS data and sat maps need to be developed and then instead of a static setback one needs to be developed that take into account the height of wind mill, path of sun, properties in the area, etc. Essentially something that will model the effect in the above video BEFORE wind turbines are built.

This is one major advantage of offshore wind (20 miles offshore). The flicker & noise fall upon nothing but waves.

[malakai2]

6. To add

Buildout on the northern plains is just getting underway, and in the locations where farms have been built, long stretches of road are subject to flicker at various points in the day. I've driven several of those stretches. Try it sometime, it will make you dizzy.

That is, dizzy while you are driving an automobile at 60 or 70 miles per hour.

[Ready4Change]

7. Trees create flicker. Never heard 'cut them down' as a solution.

Lots of trees lining the roads where I live. Each day, at certain sun angles, driving through their shadows creates a strobing effect that is very distracting.

Since this effect is horrendous enough that we shouldn't use windmills, hadn't we better start sawing down any tree that shade a highway too?

[Statistical]

8. Please watch the videos and then tell me the effect is the same as trees.

If tress spun around in a giant 800 ft circle with tip moving at 200 mph then yeah the flicker effect would be the same.

Given they don't (at least not on this planet) I think that is a reach at best.

[Ready4Change]

11. Just watched video.

When driving a car, the tree effect is far worse. It's like a fast strobe light bulb inside your eye. It is extremely distracting. I find it blinding unless I can angle the brim of my hat or move my eyes to get shade form the cars roof. Not easy, as this happens when the sun angle is quite low.

To be fair, it's only when driving, not in a house. Unlike trees, those windmills are casting shadows on his house and it's windows. The flash of those shadows is much slower, but I can still imagine it would be annoying.

OTOH, those windmills are like sundials. I'd like to know how much time per day, over the whole year, that his house is really effected. They wouldn't cast their shadows on his house, for example, at noon, nor at night or on cloudy days. (The video was shot either late in the day or early in the morning, with a low sun angle.) They also probably only hit the house at certain times of the year (since the position of the rising/setting sun changes with the season.) I honestly don't know if the windmills are so large that they flash his house most of the time, or if he filmed his video at 'just the right time.' Need more info.

[malakai2]

9. I can tell you've never driven through a turbine shadow

The way the blades sweep, the shadow cast by the tip moves rapidly over the road. As that portion of the shadow moves out beyond the roadbed, the shadow appears to slow down as the portion of the blade closer to the hub isn't moving as fast and therefore neither is that portion of the shadow. Then, as the shadow cast by the tip portion of the blade sweeps back over the road, it appears to accelerate as it sweeps across the roadbed. When the turbine rotation and car speed are properly synched, this occurs right in front of, or on, a car passing through the shadow cast. A few of these in series along the highway creates a goofy effect unlike any other shadow cast on roads. You see it in front of you, then it slows down and is in your peripheral vision for a second, and then it accelerates forward out in front of you and off the road to one side or the other. Then comes the next one, and then the next one. Where I live, that will soon be a very long chain of next ones.

Just so we're on the same page, you know how to tell the difference between a tree shadow and a turbine shadow, right? One is a massive shadow that moves a little bit from side to side, the other is a great big spinning thing that creates a strobe effect, yeah? Just so we're clear that they aren't, you know, apples and apples.

[Ready4Change]

12. I've driven in turbine shadows.

I commuted for a while in Wisconsin, along a highway that had 3 very large turbines on it's East side. I encountered the effect in the morning, as I drove south. But, if I recall correctly, the shadows on my side of the highway were traveling the opposite direction. There was a blink as the shadow passed, a long pause, then another blink.

No where NEAR as bad as the tree shadow strobe effect. Frankly, I thought they made my commute more interesting.

(on edit, they were along I-94, but whether they were North or South of Milwaukee I can't recall. Now that I think of it, might have been only 2 turbines, not 3. Cursed memory.)

[Ready4Change]

10. Just watched the vid.

I'm of two minds about it.

On one side, I can see if you moved into the country seeking total silence that the noise would get under your skin. I can also see that, at certain times of the year, and at certain times of the day during those yearly times, the blade shadows (ie: flicker) would be annoying. Despite what I'm about to write below, I can honestly understand that point of view.

On the other side, that noise is nothing compared to the barrage I have here in the suburbs. Commuters in the AM, under a major airports flight path, inconsiderate neighbors with dogs that seem to bark constantly, traffic helicopters covering the two major highways that bracket my community, on and on and on.

If I could trade my noise with that 'jet airplane' swoosh I'd do it in a heartbeat.

BTW, notice the video guys 'red shed' contained an airplane? Wonder if he has his own turf grass airfield? Wonder if the installation of the windmills has caused him issues beyond noise and flash?