Large Windmill collapse in NH

peakbagger

I guess it doesnt just happen to the small turbines

http://www.syracuse.com/news/index.ssf/2009/12/officials_hope_to_learn_why_wi.html

Editted it to reflect the correct state!

icarus

Re: Large Windmill collapse in NH

OOPS! Can you spell Liability/errors/omissions?

Tony

AntronX

Re: Large Windmill collapse in NH

Looks like it fell due to weak foundation. I wonder who was cutting corners here, contractor or client?

Edit: They also had blade problems in the past: http://www.youtube.com/watch?v=Eku6hJ-V8Ks&feature=related

Solar Guppy

Re: Large Windmill collapse in NH

Looks like the foundation split between pours? the base in that picture shows a good chunk of concrete but nothing like what would be needed to hold that tower. Also there should be rebar within the base pour so it points to either a bad design or someone didn't build the concrete base properly

GreenPowerManiac

Re: Large Windmill collapse in NH

No doubt that they'll be checking the other turbines for the same foundation issues.

Quality by design. It did what it was designed to do. How's that for an investment ?

russ

Re: Large Windmill collapse in NH

The foundation design would be based on uplift - what little concrete İ saw in the photo was a joke.

Somebody is in deep stuff - can't imagine the remainder of the foundations being done different.

Wonder what the designers last job was - or next job will be.

john p

Re: Large Windmill collapse in NH

from the photo there appears to be a length(depth) of concrete only about 6 to 7 ft.?? surely there must be more than that and that piece has just broken away from another piece below that? If the total concrete is only what is in the picture it amazing all the wind generators have not fallen over before now??
and if it has broken away so cleanly how? no reo bar in big quantity? im not an expert in structual engineering but to me the diameter of the concrete base should have been a lot larger?
lucky it was not a high rise building with people in in.
does anyone know if there are any other photos of that disaster to see more clearly what the problem was?

AntronX

Re: Large Windmill collapse in NH

Found this unrelated picture online. Looks like even proper foundation can fall.

GreenPowerManiac

Re: Large Windmill collapse in NH

That picture looks like it didn't have any anchor other than the concrete. How deep does it need to be ? Something must have hit it. The leverage alone would make it easy to knock over from the top.

john p

Re: Large Windmill collapse in NH

Found this unrelated picture online. Looks like even proper foundation can fall. but it does not look to me like a proper foundation just a fairly large thick base but not much depth when you consider the wind forces on the generator at mabe 100 to 200 ft up???
IN both cases there appears to be no reo used to help hold the concrete together below the top mounting pad?? to me there should be reinforcing bar going well into a very deep concrete post below ground.. but im no construction engineer so dont really know its just my observation

russ

Re: Large Windmill collapse in NH

Here is a photo of one foundation. Every site & situation will be different.

http://www.windturbinesfoundation.com/

Looks a bit more like what İ would expect.

Unless the foundation is sitting on bedrock İ would expect to see piles or other to further tie the foundation to the earth.

BB.

Re: Large Windmill collapse in NH

russ wrote: »

Unless the foundation is sitting on bedrock İ would expect to see piles or other to further tie the foundation to the earth.

Amen to that...

I would find it hard to believe that a simple poured footing and no pilings would even work when installed in an irrigated field (probably flood plain deposits with no underlying rock). Obviously this one did not.

-Bill

boB

Re: Large Windmill collapse in NH

Did any of you read the comments following that article ? There sure are
a lot of people that don't like renewable energy !

boB

Dapdan

Re: Large Windmill collapse in NH

Hey all,

as a civil engineer i can tell you guys having design a base for a de-methalisation tower at a natural gas plant the most critical design requirement for over turning moments. The diameter of the base is the provides the restoring moment that act against the overturning moment that is created by the wind pressure acting on the blades times the height of structure. These overturning moments basically determines the size of the base. From what I see in the picture sometime has gone wrong in the determination of that force and hence the sizing of the base. Chances are it is not the contractors fault (only if he is also the structural engineer) because they are guided by structural drawing provided by the structural engineer. Who ever the engineer is he is going to need a new vocation, good luck to him and his indemnity insurance. Also more than likely all the other are just like that one except if the foundations were design/built by others.

Cheers...
Damani

niel

Re: Large Windmill collapse in NH

boB wrote: »

Did any of you read the comments following that article ? There sure are
a lot of people that don't like renewable energy !

boB

what i think they're against is the hype and the con artists that have jumped into a go green movement that originally was a good goal before corruption set in as it was originally a back to nature type thing. re has been around long before certain elements corrupted it along with the government in selective grants both corporate and individual and let's not forget how government has taxed it in some way(not all allow its taxation). don't get me wrong here as grants to offset real re projects i don't mind to a point, but let's face it when i see a figure in the billions earmarked and little has trickled to any real results, one gets upset. sounds like a certain economic plan from the past. i'd rather see a million solar roofs, but what we see is a government bureaucracy that pockets the money on its way to distribution and then by requirements of law are whittled to a pittance of real help. i hear how they 'ran out of money' or 'the budget wasn't big enough for more results'. and we blame corrupt get rich schemes from some dealers/installers, but they're small potatoes compared to what government is doing to it and some efforts may not be realized or realized enough because government is dictating what areas of re get anything if at all.
the real cost/watt would be an astronomical figure from a governmental point of view. i could go on, but i'll curb my rant for now as it blossomed:roll:.
anyhow, it all started as a good thing.

edit to add,
yes, one can do it without the government and many have, including myself as no help was available to me back then. i also didn't ask my local municipality if i can charge my batteries with solar. i wouldn't be surprised if government made you buy a license for this stuff under the guise of only knowledgeable people should be around it. according to the government most of us aren't qualified to put in a system ourselves and they took that part to ensure only certain people can install systems rather than only qualified people. it's dumb as it is supposed to be inspected anyway isn't it? so why does it matter if only joe schmo who got certified installs it?
again i'm going on, but sometimes we need to just pull back and look at things.

peakbagger

Re: Large Windmill collapse in NH

I expect that there will be some interesting disucssions over liability. Typically industrial wind farms are built by special purpose legal enitities backed by investment firms that sell off the project to another entity soon after the project is completed. Once the sale is made, the original entity that developed the project is shut down, so there are no assets to attach if there are problems. If this farm is like a lot of other windfarms, the land is owned by someone else (like a local farmer). Therefore while the legal battles are fought, there is some unfortunate individual stuck with owning land where there are windmills ready to topple anytime the conditions are right.

Solar Guppy

Re: Large Windmill collapse in NH

Gotta love the USA and LLC's , we the corporation, for the corporation ....

russ

Re: Large Windmill collapse in NH

Between lawyers and MBA's we are totally screwed. Both specialize in how to make the most money while doing nothing worthwhile!

jacobs

Re: Large Windmill collapse in NH

In light of the low winds they were supposedly experiencing that night, and their previous blade problems, I doubt the problem was with the foundation but probably with a blade failure. Once you throw a blade, the resulting vibrations are phenomenal.....Don't ask me how I know!!!

jacobs

Re: Large Windmill collapse in NH

boB wrote: »

Did any of you read the comments following that article ? There sure are
a lot of people that don't like renewable energy !

boB

I do enjoy wind power and it's a good hobby but the problem is most people don't believe in "global warming" and neither do I. One of my morning chores is breaking and the removal of the ice from our 800 gallon stock tank. My mountain of ice is higher than it ever has been before and winter just arrived! I wonder what it'll be like in another 2 months?

john p

Re: Large Windmill collapse in NH

Jacobs.I doubt the problem was with the foundation But the photos seem to indicate there is NOreo bar protuding from the base ? Surely just a relatively small bass for such a tall structure that has a lot of energy pushing on the top side needs a lot more depth of base supporrt??

jacobs

Re: Large Windmill collapse in NH

john p wrote: »

Jacobs.I doubt the problem was with the foundation But the photos seem to indicate there is NOreo bar protuding from the base ? Surely just a relatively small bass for such a tall structure that has a lot of energy pushing on the top side needs a lot more depth of base supporrt??

Having an engineering background and having played with wind for the last 30 years, I'll admit visibly to me the foundation appears to possibly have a problem. Remember, this is an old installation and it has withstood much higher winds than were occurring when it failed and the previous problems they've experienced with these machines.

poleikleng

Fenner wind turbine collapse, aerial image

http://www.windaction.org/pictures/24818

Fenner wind turbine collapse, aerial image

Solar Guppy

Re: Large Windmill collapse in NH

Its the same picture already posted, the third post in this thread

russ

Re: Large Windmill collapse in NH

Glad people can see that the foundation looks rather skimpy - whether that was the original problem or not. Nice that it was in the middle of a field where dangers to others were minimal.

Having an engineering and construction background as being in charge of major projects around the world for 30 years - if one of my civil people was involved in a mess like that he should be running for the gate before İ get there!

jacobs

Re: Large Windmill collapse in NH

Per the media:

"The turbine, which weighed close to 190 tons, toppled over in a cornfield at about 4 a.m. Sunday, shutting down the wind farm’s 19 other turbines. No one was injured.

The collapse on Buyea Road in Fenner followed a power outage recorded at about 3:30 a.m., Enel North America spokesman Hank Sennott said. The cause remains under investigation by the company."

This isn't the first time there's been a wind turbine failure followed by a power outage.

WisJim

Re: Large Windmill collapse in NH

jacobs wrote: »

This isn't the first time there's been a wind turbine failure followed by a power outage.

But, per the quote of the news media, the power outage was first. 3:30am power outage, 4am tower collapse.

jacobs

Re: Large Windmill collapse in NH

Oops, the old brain did not communicate with the fingers. I meant.......
This isn't the first time there's been a wind turbine failure following a power outage.

westbranch

Re: Large Windmill collapse in NH

If I have it right , filling in the blanks a bit, from all the input

failure of the turbine blade starts, rotational forces are lost slowly?,

turbine generation goes down, (dont know how the output is regulated),

then blade fails completely, vibrations shake the living bjzz's out of the tower,

tower collapses...

make some sense to me, but hell I am only a Forester

From the various pics posted there appears to be something poking out of the ground around the base (200% magnification) could be rebar as there appears to be a pattern but the base is no bigger than the bottom of the tower???

and there also looks like there is just a 'hole' that the tower dropped into...???

the pic with the octagonal base didn't go too far into the ground either...

btw I don't want it on my front lawn either...

cheers..
Eric

russ

Re: Large Windmill collapse in NH

Never saw a big turbine coast down to idle from operating but the things rotate rather slowly.

For what one companies wind turbine foundation (designed for a particular soil condition İ hope) looks like please see - http://www.windturbinesfoundation.com/

BB.

Re: Large Windmill collapse in NH

My 2 cents worth of guessing... AC Mains get interrupted (in the dirtiest way possible--possibly with surges/arcs/lighting induced mess--I have seen may of the "fail over" type UPS inverters (transfer switch then turn on) not work correctly and cause a computer/controller reboot in about 1/10 power failures--my guess, because of the dirty way AC mains fail--I was never able to cause these types of failures in a lab setting with typical commercial test/qualification gear).

Electronics (possibly UPS backup) fail or get in a "weird" state and are unable to control the mechanicals. Blades fail to feather. Turbine begins to over-speed (no load, free run). Brake either fails to apply or slips/overheats as blades/wind provide torque. Eventually the brake fails, turbine over-speeds (more/faster?). Blades or windings begin to fail--setup harmonics in the blades/tower. Then it is a race about which fails first--blade, hub, harmonic caused blade crash into tower, stresses exceed strength of weakest component (concrete has very little tensile strength--unless it is of pre-stressed construction--which I did not seem to notice in any of the foundation pictures), or base failure due to liquefaction (water+earth+vibration cause soil to loose cohesion and footing is now in quick sand).

I guess if the nacelle started to turn/rotate out of control while the blades were rotating at high speed, you could get all sorts of blade/hub torque too..

From this famous Turbine destruction video taken in Demark (a rare occurance there), it apparently took a 5x rated RPM for the blade to self destruct (appeared to fail mid-blade--then a "good blade" took out the tower.

This failure (video) was the result of a brake failure and 2x over speed (looks like blade again clipped tower and took it down)...

Of course, there are many failure modes out there--the above was my guess as to why they may fail after an unrelated power outage.

-Bill