So much for Endurance…
From Louise Gray at The Telegraph:
Wind turbine collapses in high wind
A controversial 115ft wind turbine has collapsed after being hit by heavy winds.
The £250,000 tower, which stood as tall as a ten storey building, was hit by gale force gusts of 50mph.
The structure then collapsed at a farm in Bradworth, Devon, leaving a “mangled wreck”.
Margaret Coles, Chairwoman of Bradworthy District Council, said hail storms and strong winds have hit the area and the turbine, installed just three years ago, simply could not withstand the wind.
“The bolts on the base could not withstand the wind and as we are a very windy part of the country they [the energy company] have egg on their face,” she said. “There are concerns about safety.”
The Bradworthy Parish Council, who opposed the turbine, expressed concern that there was “nothing exceptional” in the speed of the winds.
Installed by renewable energy company Dulas it was supposed to have a life expectancy of 25 years.
Full story here: http://www.telegraph.co.uk/earth/energy/windpower/9837026/Wind-turbine-collapses-in-high-wind.html
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Of course, Ms. Gray calls a 50 mph wind a “high wind”, but that sort of wind isn’t an unusual event for the area. Besides, the specs for the Endurance E-3120 wind turbine say:
Given its, ahem, endurance, one wonders if the council will allow it to be reconstructed. I’m thinking no.
Looks like the blade control lost it and the blades spun up until the the turbine caught fire. Lots of pictures here.
http://www.dailymail.co.uk/news/article-2270029/UK-weather-Heavy-floods-wreak-havoc-gale-force-winds-sends-115ft-turbine-ground.html
‘It’s an ill wind that blows nobody good.” anon
Atlantic city NJ has 5 or 6 turbines running their sewage treatment plant for the city. Not sure how they did after hurricane Sandy hit the area with 100 mph winds.
Is that when the s**t hit the fan?
Boeing Dreamliners are all grounded due to battery problems.
I suggest that the UK Health & Safety Executive declare all wind turbines be locked down until the cause of these two failures (Holsworthy and Bishop Aukland) have been thoroughly investigated – this exercise to be repeated every time there is a wind turbine failure…
Lets see what effect THAT has on the willingness of landowners/developers to jump on what is basically a subsidy bandwagon…
Alan Bates says:
January 30, 2013 at 2:20 pm
The Scale was primarily founded on marine conditions. I suspect that gusts are likely to be less of a problem than on land (but others may know better …).
No, gusts are a problem at sea too. Steady wind fills your sails and drives you along, but too strong and you get tilted over so the sail spills the wind and you go slower – reduce sail area to go faster. Gusts may be a different direction to the main wind, and can shred your sails (actually a bit of a safety feature – the alternative is worse), or knock you down – hopefully you come back up – possibly a little shaken.
Steady winds of 40 knots are not too bad in themselves, it’s just that they make all those speed humps appear in the sea.
feet2thefire says:
January 30, 2013 at 11:14 pm
We don’t know it was a design problem. The structure at its base has nuts under as well as above the base plate. The entire structure rests on the bottom nuts, that is how it is leveled. If those nuts were not all tightened the same, a few over tightened nuts could have to support the structure. With the varying loads on those nuts, the threads would strip and cascade to the next. Though the overall design a was adequate, a faulty installation can cause the failure.
There are not enough details. At this time, with the facts available, the most we can say is that we don’t know.
BLACK PEARL says:
January 30, 2013 at 8:31 am
Imagine the cost of decommissioning the ones out at sea.
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the sea buries the dead.
BrianJay says:
January 30, 2013 at 9:09 am
Now hang on a minute. Didn’t the Titanic have sub standard (slag corrupted) rivets just over 100 years ago. I wonder whether this will sink the entire programme.
=============
The Titanic had an expansion gap mid-hull that ended at a sharp point. This lead to a stress fracture than cause the hull to break in two under the weight of water in the hull. This has been covered up in the official reports. The design flaw was later corrected in her sister ship without any announcement, to replace the sharp end with a circular cut out. This remains the standard engineering solution to prevent stress fractures radiating out from cuts in metal to this day.
Engineering designs often overlook dynamic loads because of the complexity in calculations, and instead rely on static loads with a safety factor. At the correct wind speed is should be expected that a free standing tower will begin to oscillate at its natural frequency, which can eventually bring down the structure, no matter how strong the materials.
Successful designs avoid the problem by making sure that the natural frequency of the structure lies outside that which can occur naturally. Ignore this rule and large buildings collapse during earthquakes and bridges collapse when troops march on them. Not because the structure is weak, but rather because of the loads imposed by harmonic oscillation.
It should be noted that force goes up as the square of the wind speed. Basically the structure failed at 1/4 of its rated strength.
A survival speed of 116 mph sound more like the survival speed with blades turning. A steel tower should be able to survive much higher wind speeds than this with the blades feathered. Trees do it all the time.
Sailboats routinely survive much worse with freestanding masts so long as the sails are down and they can be subject to much higher dynamic loads due to wave action.
ferd berple says:
> A steel tower should be able to survive much higher wind speeds than this with the blades feathered. Trees do it all the time.
Trees do it by losing branches on the windward side due to structural instability. Their crown’s shape eventually matches the flow velocity profile in their immediate environment. An of course, the result is a much reduced interaction with the wind, which is contrary to the aim of a wind turbine.
These pictures are not great, but they illustrate the idea:
http://www.flickr.com/photos/selkovjr/2295316640/
http://www.flickr.com/photos/selkovjr/4187609431/
richardscourtney says:
January 31, 2013 at 1:57 am
Not my report. A legal filing by Mid-American Holdings with the SEC. It is consistent with what plant operators and engineers of Mid-American Energy plants have told me, but an SEC filing is more authoritative than Someguyinabar. I prefer documented supportable facts as much as possible. My reply was “long winded” only because I did you the courtesy of supplying the quotes rather than making you look them up.
Get real. We know why Mid-American and Pacificorp are investing heavily in windpower. Wind power has benefits as well as costs. They are milking the $0.022 per kilowatt hour subsidy for all it’s worth and getting a 12% annual return in the process, without a fuel cost. You would find the return on investment to be used by the rate makers in the SEC filing, if you’d bother to look. By my very rough figuring the subsidy is more than the 12% return, so the ratepayers are getting part of the effect of the subsidy (my guess about half of the subsidy.) At the end of ten years the power company has a paid off asset producing electricity with no fuel costs.
They also get green energy credits, which they need and which, in excess of their needs, is a commodity they can sell.
In counting their total capacity, Mid-American uses a figure for windpower that is closer to 10% of nameplate. They also say they keep at least 7% of capacity greater than projected needs. (those percentages are of different things, so they are not comparable.) The “back up” is a number of plants modulating from say 80% of capacity to 75%, not the modulating of a single plant from 100% capacity to idle. That is a big difference in the change of efficiency.
The system has to be modulated for lots of reasons. Windpower is just one, but there is nothing unusual about reacting to its variability that isn’t already done for other reasons.
Excess is needed in the system for more than just windpower. Coal plants have mechanical problems as well and need backup. Remember when many coal plants in Texas couldn’t operate because of cold weather? A coal plant can have to be run at 80 percent capacity for months because taking it out of service for the days needed to do the repairs is too big a disruption of the system. In your line of thinking, that makes coal worthless.
Chris4692:
I am surprised that you are so frank in your post at January 31, 2013 at 9:05 am.
I had pointed out that windpower displaces conventional generating plant that have to part load when the wind is in the right range for windpower to operate. I then asked
You have replied
OK. So you admit the windfarms are subsidy farms.
As you say this makes sense for the power company, but it is a rip-off of the electricity consumers and of the tax-payers whose money provides the “$0.022 per kilowatt hour subsidy”.
As you say, this rip-off is so great that the power company gets “a 12% annual return” and can still pay off the capital cost of a windfarm in “ten years”.
Wow! And that scam is legal! In fact it is enabled by legal mandate!
This emphasises my question as to why the windpower – with its costs – exists and is used. Or, to rephrase that, why the law decrees consumers and tax-payers should be ripped off by the subsidy farms.
Your only excuse for this rip-off is a falsehood.
Nobody gets “electricity with no fuel costs”. As I explained, the throttled-back conventional plant operate at reduced efficiency so INCREASE their fuel and emissions to provide space on the grid for the windpower. That is an increased fuel cost.
Richard
Cripes! A Windmill exploded, killed 11 people and spewed toxic liquid into the Gulf of Mexico for three months! These things are a menace!!
richardscourtney says:
January 31, 2013 at 9:43 am
You are surprised that someone wants to evaluate all technologies impartially with out putting a thumb on the scale one way or the other?
There are advantages and disadvantages to windpower. The advantages that you do not want to acknowledge have to be counted as well as the disadvantages and the current regulatory environment. If the subsidy went away, there would still be windpower at some reduced level. The cost structure would adjust, site leases would not be as generous, the prices of construction would adjust down, the costs of equipment would reduce. At the moment, however, there is a subsidy. I would prefer there not be, but there is.
To the extent that the subsidy exceeds the return on investment, rate payers will benefit. Electric rates are adjusted to maintain the ROI, so the excess does not necessarily go entirely to the benefit of the utility.
Utilities have to have some reserve. Mid-American and Pacificorp maintain 7 percent excess. Which means that if the system is operating at 93 percent of capacity, it is in trouble. With the normal variations in demand, the facilities will never be operating at 100 percent of capacity. They will never have the luxury of operating the system at at capacity, they will always have to adjust, whether there is windpower or not. You want to put a thumb on the scale against windpower and attribute every inefficiency against it, when variability and adjusting to that variability are the nature of the business.
What’s the problem?
It says it has a cut off speed of 56 mph.
The winds exceeded 56 mph and the automatic cutoff kicked in, i.e. it fell over. No fancy electronics to fail.
/sarc
………the visual aesthetics of junkyard (Pat)
Yeah, dozens and dozens of spinning junkyards, lifted to the horizon. For our viewing pleasure. Spinning turbine fields are mainly massive flag plants, a symbol of successful political expansion. Poor performance is secondary and will be overlooked.
Don’t ever think that pro-agressives care one whit about feng shui; power is their game, and I don’t mean electrical power. Wind turbine fields are the Empire State Building of the growing collectivist expansion. The grotesque and shoddy, step by step, displace the elegant and functional.
Chris4692:
At January 31, 2013 at 12:11 pm you say to me
I am not at all surprised that anyone would want “to evaluate all technologies impartially with out putting a thumb on the scale one way or the other”. Indeed, I have done that. Please see Section 14 of an Annual Prestigious Lecture I had the honour of being asked to provide which can be read at
http://www.mininginstitute.org.uk/papers/courtney.html
In that lecture you will see that I also evaluate the “advantages and disadvantages to windpower”. Please note that I know of its advantages in small niche markets and I know its severe problems as a supplyer to an electricity grid. It is not that I “do not want to acknowledge” its advantages for supplying to an electricity grid: I cannot acknowledge what I have failed to find.
I know of no advantages from using windpower as an input to an electricity grid. And I know it has severe disadvantages.
You claim to know of advantages from using windpower as an input to an electricity grid. Please say what they are.
I do not consider the rip-off that I condemned in previous post is an advantage.
Richard
If I recall correctly no tender from any British firm for mast construction could be accepted on the introduction of television in Ireland some 50+ years ago, as none were prepared to design to the maximum wind speed specified. The contract went to Norway, where such winds were accepted as a valid design requirement.
Peter O’Neill said this about the Brits failing to win a contract for a TV mast construction:
> The contract went to Norway, where such winds were accepted as a valid design requirement.
Strange, if true. Was this marvel also built by Norway?
http://www.flickr.com/photos/selkovjr/6137217220/in/photostream
This design was supposed to withstand a nuclear blast in its vicinity (and it is also 50 to 60 years old). Not that it has ever been tested in a nuclear blast, but given how paranoid the customer was these days, would they not be serious enough about doing it right?
Juice: Cripes! Green energy so raised the cost of fuel in cash-strapped Greece that it is reported the forests are being clear cut and the wood smoke is so bad that air quality is approaching that of London in the 1950s (i.e. TOXIC).
ferd berple said, “A survival speed of 116 mph sound more like the survival speed with blades turning. A steel tower should be able to survive much higher wind speeds than this with the blades feathered. Trees do it all the time.”
Close. The survival speed assumes that the blades are feathered. The control system changes the blade angle based on power requirements and wind speed. Above some speed the blades will be feathered — turned edge into the wind — to reduce the force acting on the blades and therefore on the structure. The maximum wind survival number depends on the control system working and the blades feathering.
As for the bolts “failing” at the base of the tower … any structure like this will have a weakest link and if well designed that link will be the one that results in the least damage to the structure and the surrounding area. Having a blade fly off is bad because no one can predict where it will land and who it will kill. One blade off will also unbalance the turbine and cause the whole structure to fail in unpredictable ways. If the bolts are the weakest link, the structure will fall over and remain within an area that is clear of people and expensive stuff.
Richard111 said, “Looks like the blade control lost it and the blades spun up until the the turbine caught fire.”
I don’t see any evidence of fire in the linked pictures. There is some rust on one of the blades from the metal attach fixture. Other pictures show one or more tarps covering part of the wreckage. No charred remains.
climatereason says:
January 30, 2013 at 8:23 am
Anyone know the depth of concrete required per 10metre height of turbine?
I read somewhere that it was laid to a depth half the height of the turbine, but how true that was I don’t know.
tonyb
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I can not tell you anything about wind turbines but I have planted several fence posts and built several pole buildings. (I build them because the commercial outfits do not plant the posts deep enough) The rule of thumb is one third of the pole goes into the ground. So for a 6 foot fence you plant 3 feet.That is for good soil conditions on flat ground so it is the minimum. If you put torque on the post, like adding a gate you need a second post for a brace.
I think you are going to see more and more of these windmills come crashing down as they age and the metal weakens over time.
@Bill Yarber
” My guess is the failure analysis will say the installation contractor used defective or below spec anchor bolts. The “specified” bolts would not have failed at 30% of maximum load.
REPLY: Unless of course the bolts are supplied by the company. – Anthony ”
Usually the way this happens is that the installer sub-contracts installations, which are then sub-contracted to simple labourers…
” Hey, Jack – you forgot to put the bag of bolts in the van – they’re left back at the factory!”
” Never mind – they were about 1″ wide – we can pick some up at the nearest garden fence store – save us a drive…”
Brittle fracture of the steel plates and rivets was the failure mechanism of the Titanic. At low temperatures some steel are quite brittle and fail dramatically due to impact loads especially if there is a stress concentration present such as a hole or crack. Engineers today are aware of this and specify materials that retain ductility at lower temperatures if the structure is exposed to low temperatures. Since the wind turbine structure failed at loads 1/5 of the design loads, one becomes suspicious that factors such as brittle fracture are present. I’m not saying that brittle fracture was the cause here but it’s difficult to explain how a failure would occur at 1/5 th the design load. Remember that the load is proportional to the square of the wind Velocity.
Below is a description of the Titanic material failure
http://www.writing.eng.vt.edu/uer/bassett.html
“The failure of the hull steel resulted from brittle fractures caused by the high sulphur content of the steel, the low temperature water on the night of the disaster, and the high impact loading of the collision with the iceberg. When the Titanic hit the iceberg, the hull plates split open and continued cracking as the water flooded the ship. Low water temperatures and high impact loading also caused the brittle failure of the rivets used to fasten the hull plates to the ship’s main structure.”
“The first hint that brittle fracture of the hull steel contributed to the Titanic disaster came following the recovery of a piece of the hull steel from the Titanic wreck. After cleaning the piece of steel, the scientists noted the condition of the edges. Jagged and sharp, the edges of the piece of steel appeared almost shattered, like broken china. Also, the metal showed no evidence bending or deformation. Typical high-quality ship steel is more ductile and deforms rather than breaks [Gannon, 1995].
Similar behavior was found in the damaged hull steel of the Titanic’s sister ship, Olympic, after a collision while leaving harbor on September 20, 1911. A 36-foot high opening was torn into the starboard side of the Olympic’s hull ….”
Dennis Ray Wingo says:
January 30, 2013 at 10:50 pm
Your back of the envelope calculation is sligthly confusing as you used foundation data for a much bigger unit tha 50 kwh , so let’s recalculate a bit, the foundation data in the example is from an article that gives peak power ( nameplate ?) capacity of 273 Mw from 149 turbines ( taking up 10000 acres of land , what a waste , but that is side issue here ) or a little over 1.8 Mw average peak power per single turbine, so it is equivalent to somwhere around 400-450 Kw constant power equivalent , delivering ~4000 Mwh/yr or 4million KWh/year. Using your figure of 0.909 kg/Kwh Co2 savings gives 3636 tons/year so it will take a little over 10 years of problem free running to offset the Co2 generated while making the concrete used in the foundation. Now we should probaly also add to the Co2 bill the amount for 230 tons of steel used in the tower body plus maybe another 20 to 30 tons of same in the bolts and concrete reinforcing in the foundation , plus the 20-30 tons of composite materials in the propellers and the hubcasing and so on . I have no data over how much that would sum up to , but a first wild guess would be that it woulda add at least 2 – 3 years to the Co2 breakeven point. So it would first be after running for 12 – 13 years that an installation like this would have a chance to claim any Co2 savings. And if history is anything to go by, at that time it would most likely have detoriated to generating only about 65-70% of the energy it does when in it’s first year of life , it’s accumulated maintainance and running cost would probably have reached the same amount or more as the orginal installation price, and who knows maybe the subsidy period would be running out within a year of two. In other word it migth have become “unsustainable” , and the might preparing to pull the plug and walk away, leaving the cleaning up of his now usless junk to future generation ( the grandhildren of the green’s ).
“What were the greens thinking” you ask. I sure do not know, but I suspect tha tey prefer not to think at all.