# Wind farms - why are so many turbines always stopped? **URL:** \ **Category:** Factual Questions\ **Created:** [July 28, 2008, 5:01pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932 "2008-07-28T17:01:47Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Flander](https://avatars.discourse-cdn.com/v4/letter/f/8c91f0/32.png) [@Flander](https://boards.straightdope.com/u/Flander)\ **Post date:** [July 28, 2008, 8:49pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/21 "2008-07-28T20:49:19Z")
[QUOTE=FoieGrasIsEvil] 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? [/QUOTE] [Morbo] _WINDMILLS DO NOT WORK THAT WAY!!!_ [/Morbo] ---
**Author:** ![FoieGrasIsEvil](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foiegrasisevil/32/16638_2.png) [@FoieGrasIsEvil](https://boards.straightdope.com/u/FoieGrasIsEvil)\ **Post date:** [July 28, 2008, 8:53pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/22 "2008-07-28T20:53:52Z")
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. ---
**Author:** ![MarcusF](https://avatars.discourse-cdn.com/v4/letter/m/67e7ee/32.png) [@MarcusF](https://boards.straightdope.com/u/MarcusF)\ **Post date:** [July 28, 2008, 9:31pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/23 "2008-07-28T21:31:43Z")
> [@](#): > > _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. ---
**Author:** ![Tastes\_of\_Chocolate](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tastes_of_chocolate/32/3232_2.png) [@Tastes\_of\_Chocolate](https://boards.straightdope.com/u/Tastes_of_Chocolate)\ **Post date:** [July 28, 2008, 9:36pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/24 "2008-07-28T21:36:30Z")
[QUOTE=essell] IANAWFE, but I can see them shutting them down to save wear and tear when they’re not needed. [/QUOTE] 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. > [@FoieGrasIsEvil](#): > > 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? ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [July 28, 2008, 10:10pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/25 "2008-07-28T22:10:49Z")
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. ---
**Author:** ![KneadToKnow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kneadtoknow/32/3999_2.png) [@KneadToKnow](https://boards.straightdope.com/u/KneadToKnow)\ **Post date:** [July 28, 2008, 10:19pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/26 "2008-07-28T22:19:46Z")
Why did it have to be snakes? ---
**Author:** ![FoieGrasIsEvil](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foiegrasisevil/32/16638_2.png) [@FoieGrasIsEvil](https://boards.straightdope.com/u/FoieGrasIsEvil)\ **Post date:** [July 28, 2008, 11:08pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/27 "2008-07-28T23:08:56Z")
[QUOTE=MarcusF] 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. [/QUOTE] 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. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 28, 2008, 11:24pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/28 "2008-07-28T23:24:38Z")
[QUOTE=FoieGrasIsEvil] 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. [/QUOTE] 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. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [July 28, 2008, 11:33pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/29 "2008-07-28T23:33:12Z")
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://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](http://www.windpower.org/en/tour/econ/oandm.htm) ---
**Author:** ![GoodGrief](https://avatars.discourse-cdn.com/v4/letter/g/2acd7d/32.png) [@GoodGrief](https://boards.straightdope.com/u/GoodGrief)\ **Post date:** [July 28, 2008, 11:54pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/30 "2008-07-28T23:54:35Z")
[QUOTE=Tastes of Chocolate] 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. [/QUOTE] 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. ---
**Author:** ![FoieGrasIsEvil](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foiegrasisevil/32/16638_2.png) [@FoieGrasIsEvil](https://boards.straightdope.com/u/FoieGrasIsEvil)\ **Post date:** [July 29, 2008, 2:29am UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/31 "2008-07-29T02:29:02Z")
[QUOTE=beowulff] 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. [/QUOTE] 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? ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [July 29, 2008, 2:37am UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/32 "2008-07-29T02:37:06Z")
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. ---
**Author:** ![ntcrawler](https://avatars.discourse-cdn.com/v4/letter/n/34f0e0/32.png) [@ntcrawler](https://boards.straightdope.com/u/ntcrawler)\ **Post date:** [July 29, 2008, 2:52am UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/33 "2008-07-29T02:52:59Z")
[QUOTE=beowulff] 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: [![Imgur](https://live.staticflickr.com/3264/2626024807_e076a8feac_b.jpg "Wind") ](https://www.flickr.com/photos/11822576@N08/2626024807/sizes/l/) [/QUOTE] 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 ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [July 29, 2008, 3:30am UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/34 "2008-07-29T03:30:58Z")
[QUOTE=ntcrawler] 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 [/QUOTE] Those are water pumps. They are still widely used. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [July 29, 2008, 3:31am UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/35 "2008-07-29T03:31:33Z")
> [@](#): > > each nacelle has its own wind direction and speed _censors_ on top So 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 farm The 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. ---
**Author:** ![Tully\_Mars](https://avatars.discourse-cdn.com/v4/letter/t/7ab992/32.png) [@Tully\_Mars](https://boards.straightdope.com/u/Tully_Mars)\ **Post date:** [July 29, 2008, 4:15pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/36 "2008-07-29T16:15:35Z")
[QUOTE=beowulff] 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: [![Imgur](https://live.staticflickr.com/3264/2626024807_e076a8feac_b.jpg "Wind") ](https://www.flickr.com/photos/11822576@N08/2626024807/sizes/l/) [/QUOTE] 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. ---
**Author:** ![Tastes\_of\_Chocolate](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tastes_of_chocolate/32/3232_2.png) [@Tastes\_of\_Chocolate](https://boards.straightdope.com/u/Tastes_of_Chocolate)\ **Post date:** [July 29, 2008, 4:18pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/37 "2008-07-29T16:18:05Z")
[QUOTE=GoodGrief] 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. [/QUOTE] 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. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [July 29, 2008, 4:42pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/38 "2008-07-29T16:42:43Z")
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. ---
**Author:** ![Unix\_Geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unix_geek/32/19368_2.png) [@Unix\_Geek](https://boards.straightdope.com/u/Unix_Geek)\ **Post date:** [July 29, 2008, 5:01pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/39 "2008-07-29T17:01:28Z")
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. ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [July 29, 2008, 5:22pm UTC](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932/40 "2008-07-29T17:22:35Z")
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. [Previous page](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932.md?page=1) [Next page](https://boards.straightdope.com/t/wind-farms-why-are-so-many-turbines-always-stopped/457932.md?page=3)