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View Full Version : Wind farms - why are so many turbines always stopped?


Tastes of Chocolate
07-28-2008, 12:01 PM
Does anyone know why the high rate of non-spinning turbines on Upper Midwest wind farms?

Where are a couple of wind farms that have been built recently in northern Iowa and Southern Minnesota. Each of them is about 50-75 turbines. Every time we drive by, there are several of the turbines that aren't spinning. If 3 out of 50 aren't working at any given time, that's a noticable percentage of your potential energy not being produced. I've driven past 2 of these farms every other week, for the last 2 months. I can't find a pattern to which of the turbines are stopped, and yesterday one was slowing to a stop as we drove by.

Any ideas on what's happening?

friedo
07-28-2008, 12:14 PM
A. Routine maintenance
B. The other nearby turbines are using up too much wind, causing a wind deficit, or dniw, which causes an immense vacuum to slowly spread to adjacent turbines causing them to slow and eventually stop.

Harmonious Discord
07-28-2008, 12:14 PM
Perhaps it's diagnostics telling them to shutdown until repaired.

Sailboat
07-28-2008, 12:20 PM
You are seeing the handiwork of the infamous vigilante, Don Quixote de la Mancha!

Sailboat

FoieGrasIsEvil
07-28-2008, 12:27 PM
A. Routine maintenance
B. The other nearby turbines are using up too much wind, causing a wind deficit, or dniw, which causes an immense vacuum to slowly spread to adjacent turbines causing them to slow and eventually stop.
This is interesting, I'd never heard of that. Don't they attempt to compensate for that by spacing these turbines far enough apart so that doesn't occur?

gotpasswords
07-28-2008, 12:40 PM
Around here, the usual reason is that the turbines have failed mechanically and they're too expensive to repair. So, they stand there motionless, waiting for someone to replace the machinery with modern equipment.

Along the Altamont Pass, there are clusters of what were experimental designs - evidently there were a few duds, and there are simply no spare parts as the windmills were one-off creations.

Another reason for non-running windmills is maintenance - if you want to generate 100 megawatts, and you know that it takes ten windmills to do this, do you plant ten windmills, then loose generating capacity when they need to be cycled out for maintenance, or do you plant twelve, so you can have ten percent of your generating capacity offline, but still produce 100% of your target power while any given two windmills are being worked on?

gotpasswords
07-28-2008, 12:42 PM
This is interesting, I'd never heard of that. Don't they attempt to compensate for that by spacing these turbines far enough apart so that doesn't occur?
Don't stand too close to the windmills, or the whoosh will knock you over. :D

USCDiver
07-28-2008, 12:42 PM
This is interesting, I'd never heard of that. Don't they attempt to compensate for that by spacing these turbines far enough apart so that doesn't occur?


!hsooow

JeffB
07-28-2008, 12:51 PM
I don't know if this applies to the Upper Midwest, but there was a story on NPR this morning about the fact that in Texas, wind turbines (e.g. around Abilene) are generating more electricity than the power lines (to Dallas-Fort Worth) can transmit. When the lines are at full capacity, the turbines shut down.

beowulff
07-28-2008, 01:02 PM
I don't know if this applies to the Upper Midwest, but there was a story on NPR this morning about the fact that in Texas, wind turbines (e.g. around Abilene) are generating more electricity than the power lines (to Dallas-Fort Worth) can transmit. When the lines are at full capacity, the turbines shut down.
I drove through this wind farm a few weeks ago. The wind was blowing steadily and pretty hard, and most of the turbines were turning. Here's a photo:
http://www.flickr.com/photos/11822576@N08/2626024807/sizes/l/

Santo Rugger
07-28-2008, 01:24 PM
I drove through this wind farm a few weeks ago. The wind was blowing steadily and pretty hard, and most of the turbines were turning. Here's a photo:
http://www.flickr.com/photos/11822576@N08/2626024807/sizes/l/Umm, none of the turbines in that picture are spinning. :dubious:


:smack:

garygnu
07-28-2008, 01:26 PM
I drove through this wind farm a few weeks ago. The wind was blowing steadily and pretty hard, and most of the turbines were turning. Here's a photo:
http://www.flickr.com/photos/11822576@N08/2626024807/sizes/l/
But the turbines in that picture aren't turning...

beowulff
07-28-2008, 01:59 PM
But the turbines in that picture aren't turning...
Obviously, you aren't drinking enough. :p

Max Torque
07-28-2008, 02:24 PM
I've been told by folks who've been involved in the design and construction of some of those large windmills that they really don't take advantage of winds above 30 MPH or so (or was it 25? been a while, can't recall exactly), and that they can in fact be damaged by wind that exceeds their useful limit. After that, I supposed that shut-down windmills had either been damaged, or were purposely shut down to avoid being damaged.

Harmonious Discord
07-28-2008, 02:24 PM
That's the design around Fond du Lac Wisconsin. The individual blades are longer than the silos are tall on farms. I think from what I read it's a turbine by Vestas.

Wisconsin wind farm projects. (http://www.renewwisconsin.org/windfarm/windwisconsin.html)
Specifics about the turbines south of Fond du Lac. (http://www.airventure.org/2008/news/080619_turbines.html)

An email to one of the energy companies would likely get a response from them.

UncleRojelio
07-28-2008, 02:43 PM
I don't know if this applies to the Upper Midwest, but there was a story on NPR this morning about the fact that in Texas, wind turbines (e.g. around Abilene) are generating more electricity than the power lines (to Dallas-Fort Worth) can transmit. When the lines are at full capacity, the turbines shut down.
We are working on fixin' the problem (http://www.npr.org/templates/story/story.php?storyId=92638565). All it takes is more money.

pravnik
07-28-2008, 03:19 PM
I don't know if this applies to the Upper Midwest, but there was a story on NPR this morning about the fact that in Texas, wind turbines (e.g. around Abilene) are generating more electricity than the power lines (to Dallas-Fort Worth) can transmit. When the lines are at full capacity, the turbines shut down.That story was just ending when my alarm radio clicked on this morining. Very odd to hear our little burg mentioned in the news for any reason. Prairie Home Companion's coming to town, too! Yeehaw!

Tastes of Chocolate
07-28-2008, 03:28 PM
Several people have mentioned maintenance. Is there anyone who works in the field? It just seems odd (and uneconomical) that 5-10% of possible power generation is being lost at any given time, because of lack of maintanence on generators that have been installed in the last 3 years.

As for wind speed - wouldn't that apply to all the generators, and not just a couple of them? These are farms of 50 identical windmills.

essell
07-28-2008, 03:43 PM
Several people have mentioned maintenance. Is there anyone who works in the field? It just seems odd (and uneconomical) that 5-10% of possible power generation is being lost at any given time, because of lack of maintanence on generators that have been installed in the last 3 yearsI know there are some power stations that are only turned on at peak times or when otherwise needed.

Wind power isn't free from running costs. The farms will need services like a car. Either dependant on time or 'mileage'.

IANAWFE, but I can see them shutting them down to save wear and tear when they're not needed.

FoieGrasIsEvil
07-28-2008, 03:48 PM
Don't stand too close to the windmills, or the whoosh will knock you over. :D
:smack:
Goddammit!
In this age of developing alternative sources of energy, and me knowing little about wind power, for instance, here I stand all green and ready to soak in knowledge and I get a whopper of a whoosh...by a fucking windmill topic, no less!
Gah to the lot of ya!
:)

Flander
07-28-2008, 03:49 PM
This is interesting, I'd never heard of that. Don't they attempt to compensate for that by spacing these turbines far enough apart so that doesn't occur?





WINDMILLS DO NOT WORK THAT WAY!!!!

FoieGrasIsEvil
07-28-2008, 03:53 PM
I am wondering how much maintenance a windmill/turbine would really need. I suspect that there would be regular lubrication intervals, worn bearings of some sort...I am pretty fuzzy on generators powered by something other than petrol fuels, but aren't there other wearable parts that would need replacing over time? Gears? Driveshafts? Seals?

It would seem that a windmill as a power generation device should be pretty maintenance free and a simple device, really. If it's only asked to do one thing, over and over, and it has an upper limit as to how fast they are allowed to turn due to the likelihood of damage, how often can the intervals be?

You would think that these things could run for a really long time with very little maintenance.

MarcusF
07-28-2008, 04:31 PM
Originally posted by FoieGrisisEvil:
It would seem that a windmill as a power generation device should be pretty maintenance free and a simple device, really. If it's only asked to do one thing, over and over, and it has an upper limit as to how fast they are allowed to turn due to the likelihood of damage, how often can the intervals be?That might be true if the wind blew at a constant velocity from a fixed direction! As it is the they have to speed up, slow down, feather the blades and change the direstion they face and - inevitably - they suffer from fatigue problems as the blades flex, etc, etc.

Tastes of Chocolate
07-28-2008, 04:36 PM
IANAWFE, but I can see them shutting them down to save wear and tear when they're not needed.

I'd wondered about this, but it was a July afternoon in Iowa. It was over 90 degrees, and a very high dew point. Just about every building in the area had to be running their A/C.

I am wondering how much maintenance a windmill/turbine would really need. I suspect that there would be regular lubrication intervals, worn bearings of some sort...I am pretty fuzzy on generators powered by something other than petrol fuels, but aren't there other wearable parts that would need replacing over time? Gears? Driveshafts? Seals?

That's what I was trying to ask in the first place. Maybe I just worded it badly. Does it really make sense that 5-10% of your windmills would be down, at any given time, due to maintenence?

friedo
07-28-2008, 05:10 PM
FWIW, there was an episode of Dirty Jobs in which Mike works with a wind turbine maintenance crew. They had to climb way the hell up inside the turbine nacelle to lube up a bunch of parts, replace some wiring, and be on the lookout for deadly deadly snakes.

KneadToKnow
07-28-2008, 05:19 PM
Why did it have to be snakes?

FoieGrasIsEvil
07-28-2008, 06:08 PM
That might be true if the wind blew at a constant velocity from a fixed direction! As it is the they have to speed up, slow down, feather the blades and change the direstion they face and - inevitably - they suffer from fatigue problems as the blades flex, etc, etc.
Now we're getting somewhere. I wondered how they altered the angle of the fan blades to collect energy from wind's ever-shifting direction.

I suppose that is why there are certain target areas that are better than others for wind farms (that sounds weird!) where the wind generally blows in the same direction most of the time, like when I lived in Hawaii...the tradewinds always blew in the same direction 3/4 of the year, and when it changed direction, it generally meant rainy weather was afoot.

But certainly if we have mastered the high rpm's of prop airplanes, we can keep wind turbines and their fan blades running with little maintenance. Although that may be an apples/oranges comparison due to the sheer size of the blades on wind turbines.

beowulff
07-28-2008, 06:24 PM
Now we're getting somewhere. I wondered how they altered the angle of the fan blades to collect energy from wind's ever-shifting direction.

I suppose that is why there are certain target areas that are better than others for wind farms (that sounds weird!) where the wind generally blows in the same direction most of the time, like when I lived in Hawaii...the tradewinds always blew in the same direction 3/4 of the year, and when it changed direction, it generally meant rainy weather was afoot.

But certainly if we have mastered the high rpm's of prop airplanes, we can keep wind turbines and their fan blades running with little maintenance. Although that may be an apples/oranges comparison due to the sheer size of the blades on wind turbines.
Usually, the angle of the blades is only changed to control rotational speed. Generally, the entire nacelle rotates to face the wind. Still, there are a lot of complex, heavy-duty linkages to wear out.

gotpasswords
07-28-2008, 06:33 PM
It took some digging, but it looks like a typical wind turbine is taken down for scheduled maintenance twice a year, and the maintenance generally takes 12-18 hours. As a result, you can expect each unit to be down for 2-4 days per year.

The entire wind farm will be taken offline twice a year for about 12 hours to perform maintenance on the electrical substation.

Unless you have a large staff, you probably can't manage to do turbine maintanance and substation maintenance at the same time, so collectively, each turbine will be offline five days a week, or about 1.5% of the time. And that's assuming you have a good maintenance crew that can get things done quickly.

Wind turbines cost in the area of $1.3 - 1.7 million per megawatt of generating capacity to install. Expect to pay 1.5 - 2% of this cost per year per turbine for maintenance. In other words, a new 2 MW wind turbine will cost roughly $3 million to install, and you'll spend $60,000 a year to maintain it. If something actually breaks, costs and downtime will naturally go up.

Sources:
http://pepei.pennnet.com/display_article/293559/6/ARTCL/none/none/1/Wind-Turbines:-Designing-With-Maintenance-in-Mind/
http://www.windpower.org/en/tour/econ/oandm.htm

GoodGrief
07-28-2008, 06:54 PM
I'd wondered about this, but it was a July afternoon in Iowa. It was over 90 degrees, and a very high dew point. Just about every building in the area had to be running their A/C.


I live in NW Iowa where these things are going up like crazy right now. I'm guessing you were on Highway 9 between Spirit Lake and Sibley? The closest one to us at the moment is about a mile away. My understanding is the electricity generated by the ones in our area does not benefit the locals, but is sent to Florida - at least by the ones owned by Florida Power and Light, which is quite a few.

FoieGrasIsEvil
07-28-2008, 09:29 PM
Usually, the angle of the blades is only changed to control rotational speed. Generally, the entire nacelle rotates to face the wind. Still, there are a lot of complex, heavy-duty linkages to wear out.
OK. So if the nacelle rotates, that's a moving part that needs PM. I did not know that, although it makes perfect sense. Is there a remote control station whereby a human controller watches a windsock and decides to alter the direction the turbines are facing in accordance with the change in wind direction, or are they automated to do so?

friedo
07-28-2008, 09:37 PM
They're all automated AFAIK. I recall from the Dirty Jobs episode that each nacelle has its own wind direction and speed censors on top so it can adjust itself accordingly.

ntcrawler
07-28-2008, 09:52 PM
I drove through this wind farm a few weeks ago. The wind was blowing steadily and pretty hard, and most of the turbines were turning. Here's a photo:
http://www.flickr.com/photos/11822576@N08/2626024807/sizes/l/

What's that little old-style one used for? Don't mean to hijack the thread but you always see those in pictures of the stereotypical farm

beowulff
07-28-2008, 10:30 PM
What's that little old-style one used for? Don't mean to hijack the thread but you always see those in pictures of the stereotypical farm
Those are water pumps.
They are still widely used.

Chronos
07-28-2008, 10:31 PM
each nacelle has its own wind direction and speed censors on topSo they provide power, but they don't want anyone to know about it? ;)

What's that little old-style one used for? Don't mean to hijack the thread but you always see those in pictures of the stereotypical farmThe places which are good for wind power now were also good for wind power in the past. I'm guessing that that was one which was used for pumping water on a farm or what-not, and just never got taken down. Since it's there, it makes for a good picture.

Tully Mars
07-29-2008, 11:15 AM
I drove through this wind farm a few weeks ago. The wind was blowing steadily and pretty hard, and most of the turbines were turning. Here's a photo:
http://www.flickr.com/photos/11822576@N08/2626024807/sizes/l/
They must be steadily expanding that place. Almost every day, as I ride home from work, I see a convoy of trucks carrying blades for the turbines headed west. Those things must be at least 100 feet long. There seem to be two different sizes. There's a smaller size of which they can put two on a trailer. Those look to be only about 70-80 feet long. Then there's the larger size that they carry one-at-a-time. That's one long load on the highway.

Tastes of Chocolate
07-29-2008, 11:18 AM
I live in NW Iowa where these things are going up like crazy right now. I'm guessing you were on Highway 9 between Spirit Lake and Sibley? The closest one to us at the moment is about a mile away. My understanding is the electricity generated by the ones in our area does not benefit the locals, but is sent to Florida - at least by the ones owned by Florida Power and Light, which is quite a few.

The ones I see the most are the two wind farms close to Mason City. One just to the north and one just to the east.

Qadgop the Mercotan
07-29-2008, 11:42 AM
I too wonder why a percentage of them are generally not running, on any given day. I drive past over 80 of them twice a day, and it seems at least 2 or 3 windmills have their blades feathered and are idle. And it's generally a different 2 or 3 or more, from one day to the next.

I've not noted maintenance crews at the idle ones, either.

This is a new windmill farm, and these have all been up for over 6 months now.

Unix Geek
07-29-2008, 12:01 PM
Mike Rowe from Dirty Jobs has all the answers. Like how does a copperhead get into the top of a turbine. The Oklahoma Wind Farm Technician episode will replay on August 19th at 9:00PM Eastern on the Discovery Channel.

lieu
07-29-2008, 12:22 PM
I just called someone who both installs them and has a number of them on his ranch. He mentions three things that'll cause some to be shut in; the transmission line capacity, that a computer shuts them down immediately when something is amiss (breakdown) and that there's an appreciable amount of routine maintenance required. Collectively, it probably should be common to see 5 to 10% shut in at any given time.

Qadgop the Mercotan
07-29-2008, 12:46 PM
I just called someone who both installs them and has a number of them on his ranch.
Thanks, lieu! :cool:

Cardinal
07-29-2008, 12:51 PM
Mike Rowe from Dirty Jobs has all the answers. Like how does a copperhead get into the top of a turbine. And what is it eating up there? Are rodents making nests up there, only to have to run all the way down to get out and feed?

Qadgop the Mercotan
07-29-2008, 01:00 PM
Mike Rowe from Dirty Jobs has all the answers. Like how does a copperhead get into the top of a turbine. The Oklahoma Wind Farm Technician episode will replay on August 19th at 9:00PM Eastern on the Discovery Channel.
I saw that one. It only had some of the answers.

Tastes of Chocolate
07-29-2008, 03:18 PM
I just called someone who both installs them and has a number of them on his ranch. He mentions three things that'll cause some to be shut in; the transmission line capacity, that a computer shuts them down immediately when something is amiss (breakdown) and that there's an appreciable amount of routine maintenance required. Collectively, it probably should be common to see 5 to 10% shut in at any given time.

You're my hero of the day.

FoieGrasIsEvil
07-29-2008, 03:19 PM
Awesome.