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  (Source: rochesterturning.com)
One more complaint about the wind power industry falls to the...well, wind

Wind power usage is growing at a steady rate.  In the U.S., Texas plans to unleash a massive amount of capacity by connecting remote areas with turbines to their main power gridIn China, wind power is growing so fast the targets have to be constantly be revised upwards.

However, for all its potential, wind power has some key criticisms.  One major problem is the noise.  When wind turbines are placed in populated areas the noise they make when displacing air can be unpleasant.  It can range from a whistle to a clatter.  As a result, turbines in populated areas are forced to artificially limit their speeds to lower noise.  This however results in lower power output.

Now researchers at the Fraunhofer-Gesellschaft Institute have developed technology to effectively cancel this noise, allowing full-speed operation.  To accomplish this, they first identified the significant sources of noise -- the rotor blades and the cogwheels in the gear box.  They then examined how these sources transmit vibrations into the central tower, causing it to produce a whining pitch that is considered very unpleasant.

André Illgen, a research associate at the Fraunhofer Institute for Machine Tools and Forming Technology IWU in Dresden, explains, "People find these monotone sounds particularly unpleasant, rather like the whining of a mosquito."

As the wind speed varies, the pitch of the noise varies as well.  This makes cheaper passive dampening systems ineffective.  Current active dampening solutions work better, but they are typically expensive and require rebuilding of the gearbox, as well.

Researchers with IWU worked with a number of other teams -- including researchers from Schirmer GmbH, ESM Energie- and Schwingungstechnik Mitsch GmbH and the Dr. Ziegler engineering office -- to develop a better active dampening solution. The researchers first attached sensors to the gearbox which measured vibrations from the gears and rotors.  This information is passed to a control system.

After processing the control system sends a signal to piezoelectrics on the gearbox's bearings that connect it to the pylon.  The piezoelectrics transform electric control signals into precise mechanical vibration.  The control unit uses this vibration to counteract the resonance in the system, by "pushing" in the exact opposite direction.  The researchers describe this as creating an "anti-sound".

While this kind of sound dampening technology is common in other fields, the key aspect of the research was the adaptation of it to the windmill form factor.  The new tech is mountable and should be relatively inexpensive.

Researchers already have tested a working scale model.  They plan to soon begin full field tests.  Assuming they continue in their early success, one of the major complaints about wind power may soon be on its way to being removed.  The speed may still need to be limited to protect the turbines in heavier winds, but overall this will raise their operational speed and output.



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RE: Dilute sources of energy
By masher2 (blog) on 8/13/2008 2:35:53 PM , Rating: 2
They may look like fiberglass, but they're probably coated steel tubes. I've never seen a fiberglass tower on a commercial wind turbine. Here's a list of every windfarm currently in operation in Pennsylvania. All are from manufacturers who use steel tube towers:

http://www.awea.org/projects/projects.aspx?s=Penns...

According to a recent study, wind power uses 5 times the concrete and 10 times the steel per MW-hour generated as does nuclear power. This is the primary reason wind power has both a greater cost and larger environmental footprint.


RE: Dilute sources of energy
By Motamid on 8/13/2008 9:21:55 PM , Rating: 2
I would be interested in seeing the details of that study. Wind I agree is definitely more costly per MW-hour than nuclear when it comes to price. However I don't think that building requirements alone accurately reflect the environmental footprint they leave. A nuclear plant requires a constant intake of uranium to operate.

Taking this into consideration the environmental cost of nuclear power also includes that from the mining, refining, transportation, recycling, and later storage of the nuclear material. Particularly the mining of uranium and storage of the nuclear waste seem to have a rather large environmental footprint for it to be overlooked.

Nuclear is efficient, cheap, and relatively friendly to the environment, but it isn't a miracle cure. I'm all for expanding nuclear to be a major source of our electrical generation, however it shouldn't be the only clean source of energy that we pursue.


RE: Dilute sources of energy
By EricMartello on 8/14/2008 12:06:49 AM , Rating: 2
Nuclear power is probably the best overall choice, but it does have one major issue - water requirements. One plant requires huge amounts of water on a daily basis for normal operation, and once the water is cycled thru the plant, it becomes contaminated with radiation.


RE: Dilute sources of energy
By TomZ on 8/14/2008 8:03:03 AM , Rating: 2
quote:
once the water is cycled thru the plant, it becomes contaminated with radiation.

Uh, no - it doesn't get contaminated with radiation - it just gets hot, that's all.

And while you're right that it does require a lot of water, it doesn't really require that much more than a fossil fuel plan of similar output.

http://www.aph.gov.au/library/pubs/rn/2006-07/07rn...


RE: Dilute sources of energy
By monkeyman1140 on 8/18/2008 10:12:26 AM , Rating: 2
One thing that is never discussed in the nuclear power generation debate is an obvious one. There is a limited amount of uranium in the earth's crust, and its getting harder to find all the time. The amount of processing required to turn ore into fuel is costly, and spent fuel cannot be used again cheaply. Reprocessing it generates even more radioactive waste. Right now there are hundreds of storage facilities all over the planet holding spent fuel. If the water pool ever drains in one of the facilities then an ecological disaster would result.


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