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Wind Turbines 2

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Significant power transmission issues exist state side. Most of the US is on a grid with capacity issues during peak loads. Expect some of that "shovel ready" infrastructure moola headed toward power transmission. The Texas grid is independent of the other power grids with DC links that could prevent the spiral down during a northeastern brownout.

Although congress threw away 700 gigabuck toward the banks and is making plural gigabuck bad loans to the failing auto industry, most Norte Americanos consider hundreds of billions to be incomprehensible.
 
OK, got over to the wind farm in Casares, Malaga, Spain (N 36.409867° E 5.282712°) where there are 35 large (1 MW ? ea)wind turbines installed on a ridge before arriving at the town of Casares. These don't do much for the view IMO, either, but its better than smokestacks I suppose. I just know that before these sprouted, it was much prettier.

A short video is posted at,

I think the noise can be best described as "wind turbine snoring." There is a steady humm from the generator, a swish from the blades and seems to be an extra wheeze when a blade passes the column. I was able to get into the farm, as the gate was open and took the video right next to the column of the first one I reached. The wind was relatively light, probably 10 mph while I was taking the recordings. I was there on a day when the wind was 25-30 mph once before and the noise was considerably louder. Easily audiable from several hundreds of meters away and I believe it was much louder at that distance than the recording I took yesterday. I didn't notice the generator humm from a far distance, but standing below one it is audiable.

In any case, last time I had a hotel with thin walls, the guy next door kept me up all night and he wasn't this loud. Maybe I'm just too sensitive, as I'm pretty used to the usual peace and quite we have around here most of the time. Well, except for the cracks of the golfers teeing off from #2 and ... it is true that the summertime frogs get pretty roudy when they're partying hard down at the water trap all night. Have to check and see what's in that water.

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)
 
A good powerpoint file on the ERCOT wind turbine system upset of 24 Feb 07 is on the attached link. Loss of 1.5 GW in a 90 minute period due to uniform tripping at a 55 mph windpseed initiated the rapid, unpredicted loss of generation, and uncontrolled re-loading of the turbines led to later system disturbances.

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Hence the need for the 800 B above to create a robust grid. No doubt there will be some enterprizing company that will sprout up with 1024 huge mobile flywheels for lease.

Do they make noise?

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)
 
BigInch, those are the same Turbines we have here in Central Illinois.

You are right, they are just way too loud, you can barely hear yourself think.

Then a Cricket chirps and you about jump out of your shoes.

There may well be a problem with the grid bouncing, but to say they have a noise issue is a bit overboard.

Typically my house whistles louder in the wind than those turbines.
 
Like I say, maybe I just don't like the noise however many dBa it may or may not actually be registering and remember ... the wind was minimal when I made the recording. Actually I think the worst thing about them can be the shadow flicker effect.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)
 
BigInch,

All other issue involving wind aside, don't you think "I don't like that they cause the light to flicker on my drive home" is a pretty poor reason to oppose a technology?
 
Wrong. I don't oppose it. As most of us are aware of the advantages, I'm simply discussing some of the disadvantages of the technology. I will also admit that most of those negative aspects can be controlled for the most part with adequate setbacks that, if respected by utility companies, should make them relatively benign additions to the landscape for the most part. I agree they are better than nuclear power plants, belching smokestacks, biofuels made from edible plants, diesel power drilling rigs, heck, just about most anything, but nothing says I have to like everything about them, right?

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)
 
The flash factor is why some companys don't place there towers near peoples homes, or so I am told.

My bigest peves with wind power is it usually arrives when we don't need it, mainly at night. And you can't shedule it, so you have to follow it with a fossel unit, which adds wear and tear on the fossel unit to try to ramp up and down that much.

Now if you can store the wind power some how, and release it as it is needed, I don't have a problem.
 
Another and apparently unexpected problem with turbines - icing:
(NIMIBY's please note: this wind turbine in Norfolk is owned by a Cornish power generating company....)
Note also the comments on light flashing and noise.
I would suggest that even the most dedicated supporters of wind trubines would be concerned about the location of this one.

JMW
 
Strange that it would be ... unexpected, being outside in the cold, wind, rain, etc.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)
 
Found a vendor noise curve. Attch. Its not my imagination. This one begins at 100 dB



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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
 
100dB?
Great, that means that just as townies can move to the country and get church bells silenced and farmers hauled off to jail because their animals make too much noise and/or smell and they spread smelly stuff on fields that will be used to grow crops, we can hope to have wind turbines either turned off altogether or have restrictions imposed on when they can be used.

PS, in the chart, why not wind speed at the hub height, why 10m?


JMW
 
Lowest velocity in the blade disk diameter?

There are restrictions on where they can be used in most places already, but there are a few articles I've seen where the local residents say the restrictions have been ignored, or the area simply rezoned, by local town councils over some objections. If the existing restrictions were followed, it would have been doubtful that anybody would have complained about noise.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
 
It seems to me that there ought to be some standard procedure for determining the effective noise generated based on a variety of factors and derived from a study which should surely include some consideration of tower height, diameter and ground effects.

The wind turbine is not, close to, a point source but with sound generated across the swept region.
Measuring the sound at the hub is as reasonable as any other approach. We are not, one presumes, to believe that there is no noise at the hub, just that at the hub the noise generation may be less, as you say, due to the local velocity, but it may well be that along the hub axis is the most intense noise as all noise generating points of the swept plane are equidistant from that axis.

Making a local measurement close to the swept plane but radially displaced is not the most effective or representative method.

JMW
 
I think the highest reading would be in the region of the blade tip (it is the highest velocity of anywhwere on the blade). Also as it passes the tower column, there seems to be an increased whooshing sound when the blade becomes vertically aligned with the column. Perhaps the velocity of air spilling off the blade and then passing around the tower is slightly increased.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
 
Measuring noise at the blade tip may be problematic. Would it be more reasonable to measure at some distance where people might actually be. Say 100 foot from the base of a tower, at a heigth of say 6 feet.
 
I think they were probably trying to establish the maximum sound level, rather than what a person could typically hear standing under it; te idea being to be able to predict sound levels in any direction from the point of maximum energy. It would surely be easier to work with the accoustic radiation if you know the maximum value at a point, rather than take the measurement at 6ft, reverse it to 10 m altitude to obtain the max energy level, and then go out from that point in any direction. Hey, but I'm just guessing.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)
 
Note that that graph is a sound power level (SWL), not a sound pressure level. So you need to do some maths to determine what someone would hear at a given distance, and you don't have the directivity graph so you can't really do that. A person talking loudly has a SWL of around 90 dBA.

Cheers

Greg Locock

SIG:Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
 
Here's a sad sight:
However, we are assured this £1million wind turbine did not fold up because of UFOs but because of the far less interesting (to the public) mechanical failure.
STill, "Wind Turbine Struck by UFOs" made for interesting reading.

JMW
 
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