Story by Eric Worrall –
![wind_turbine_bearings[1]](https://wattsupwiththat.files.wordpress.com/2014/08/wind_turbine_bearings1.jpg?quality=83)
A few years ago, I used to know a senior wind turbine engineer. One evening, over a few beers, he told me the dirty secret of his profession:
“The problem is the bearings. If we make the bearings bigger, the bearings last longer, but making the bearings larger increases friction, which kills turbine efficiency. But we can’t keep using the current bearings – replacing them is sending us broke. What we need is a quantum leap in bearing technology – bearing materials which are at least ten times tougher than current materials.”
At the time there was very little corroborating online material available to support this intriguing comment – but evidence seems to be accumulating that bearings are a serious problem for the wind industry.
Siemens citing bearing failures as part of the reason for a substantial fall in profit;
http://www.offshorewind.biz/2014/05/07/siemens-energy-division-profit-down-54-pct/
In the announcement of the opening of a new Siemens research facility;
http://www.greenoptimistic.com/2013/03/19/siemens-wind-turbine-research/
“… The Brande test center would evaluate the main parts of their wind turbines such as main bearings …”
http://www.geartechnology.com/newsletter/0112/drives.htm (an attempt to make direct drive turbines, to reduce bearing wear)
“… More accurately, it is typically the bearings within the gearbox that fail, in turn gumming up the gearbox, but that’s a story for another time. …”
http://en.wikipedia.org/wiki/Burbo_Bank_Offshore_Wind_Farm
“… During summer 2010 Siemens decided to change the blade bearings on all 25 turbines as a pre-emptive measure after corrosion was found in blade bearings found on other sites. …”
Of course, there is the occasional video of catastrophic turbine failure;
Suggestions the industry is trying to conceal the scale of the turbine fire problem;
All of which creates an interesting question – just how much of our money is the government prepared to waste, to keep their wind dream afloat? If the costs are far greater than the industry admits, how long is the wind industry going to carry that additional hidden cost, before they try to push the costs onto taxpayers, or abandon wind technology altogether?
http://www.dailymail.co.uk/news/article-2116877/Is-future-Britains-wind-rush.html
From the original post:”Suggestions the industry is trying to conceal the scale of the turbine fire problem” (citation omitted)
The article cited says there are 120 wind turbine fires annually out of 200,000 turbines worldwide. One fire per every 1,666 turbines. If the expected life of a turbine is 10 years, that means a 0.6% chance that sometime in its life it will catch fire. That does not seem to be a rate that is of cataclysmic importance to the industry.
Every time one of these articles comes out, the opponents all decry every technical problem as being cataclysmic and impossible to overcome. Extra bearing maintenance is just another technical problem. All equipment has to be maintained. Maintenance is part of the cost of the project, known in advance. In the scale of investment in these projects, maintenance is not a large fraction of the initial present worth of the project. An increase in maintenance cost will not be of great importance.
All the technical problems can be overcome. They are overcome every day. It’s unfortunate that subsides skew the evaluation of the economic evaluation but it remains that wind power is a technically viable energy source.
Technically viable, but not economically viable. Elementry!
BJHanson says “I mean, the current uptick in renewable energy production is just market forces at work. The public wants renewables, and the market is in a place where it obviously pays.”
In my state the local power company is REQUIRED to provide some percentage of “green” power. To meet this they recently purchased a couple broken down wind farms that were all put up with subsidies. Now I have to pay for your cause, instead of YOU paying for your own cause. Right out of the liberal playbook, nothing to with science, finance, or good ideas. Please use your own money for your own great ideas, thanks.
Life cycle costs rule – bearings are critical
Extremely high durability bearings HAVE been developed. – by Pratt & Whitney – for a $> 1 billion RD&D investment.
The Billion-Dollar Bet On Jet Tech That’s Making Flying More Efficient
Wind turbine companies need to persuade Pratt to license its ultra reliable bearing technology.
I think the problem is going to be cost, not that Pratt won’t license the technology. Pratt probably farmed out bearing development to a subcontractor here in CT, more than likely, New Balance or whatever they are calling themselves now. I interviewed there a long time ago and they were doing amazing things with carbide coated balls then.
Total Cost of Ownership is a key component of calculating the true business case (Net Present Value) of any initiative. The other trick is identifying “incremental” value over current options (fossil fuels) because they are the default option in this case. Most people fail at one or more of those three concepts (TCO, NPV, identifying “incremental” from “absolute”).
The only benefit of government subsidized renewables with negative business cases is that it does spur the development of these technologies such that problems with TCO such as the one identified in this article can perhaps be overcome in shorter timeframe. That being said, one could argue that subsidies undermine the incentive to solve some problems as well by propping the technologies up artificially.
Turns out that energy ignorance is apparently epidemic amongst U.S. Senate Democrats – years ago Max Baucus (who, unbelievably, was chairman of the Senate Energy committee) claimed that wind turbines would put OPEC out of business, not realizing that, even back then, virtually no electricity was being produced using oil based fuels. The other day, Chuck Schumer gave the same reason as one of the benefits of wind power.
Hawaii would seem the perfect spot for wind turbines, not only because of the tradewinds, but because Hawaii has to import the oil and coal to run her power plants and the costs produces the highest rates in the United States, at 38 cents per kilowatthour, three times the national average, and more than twice as much as the next most expensive U.S. electric rates.
When my wife and I did a vacation on the Big Island a few years ago, we were struck by the large number of rusting, abandoned wind farms we saw while driving around the island. I guess the subsidies gave out.
@ur momisugly BJ Hanssen (@ur momisuglyBJHanssen)
Upi ask a reasonable question:
“Why not support the development of renewables?”
Here are some perspectives to answer this question.
– “Renewable energy” is a misnomer, all energy costs a lot. There ain’t no such thing as a free lunch (TANSTAAFL).
– Wind and solar have become rent seeking, if not moral hazard, based industries.
– If wind is to be viable, it must be developed privately. government subsidy distorts the r&d cycle, as we see, and leaves it vulnerable to government financial changes. Think of Spain sumping solar.
– The wind industry in particular has been deceptive in its claims of safety, enviro impact (birds, etc. ), stated capacity vs. actual output, financials and economics.
These windmills are used to mark the position of subsidy farms their investors have no interest in the provision of energy, only in harvesting subsidies which currently provide an unrivaled government guaranteed return on investment, any energy output is just a byproduct of the subsidy farming. As soon as the subsidies start to reduce or the government guarantees go the way of all such guarantees, the investors will move their money to another area where there are guaranteed returns on investment. With no money invested the life-cycle costs become unsustainable, the company running the subsidy farm declares bankruptcy and the dead and corroding windmills will remain as towering monuments to political stupidity.
“Maybe instead of a single overhung bearing, they need to go to a double-bearing — a bearing on both sides of the rotor-hub.”
That would nearly double the friction, reducing efficiency greatly.
Chris4692 technically viable maybe but at what cost? Economically viable certainly not especially when you consider that coal, gas and nuclear can function 24/7. Of course wind and solar could function without backup if you are prepared to accept that as in Germany during winter 2012/13 when for three months I believe all of their wind and solar failed to generate just one MW of electricity, exactly how do essential services function under that regime? Take just one example exactly how do you run a hospital 24/7 on an interruptible supply of electricity without fossil fuel backup and if you have access to fossil fuel why have wind turbines when all they do is add to the cost, why run two systems in tandem, exactly what is the purpose, tell me why when as in the case of Germany their Co2 continues to rise simply because of the excessive ramping necessary to ensure the viability of wind and solar. Effectively German home owners are paying an excessive price for electricity just to promote the myth that being green is viable when without backup from 16,000 Czechoslovakian and thousands of German brown coal miners German industry the pillar of its thriving economy would die the same day. Why would you want to overcome the technical idiocies of wind turbines presumably to protect the jobs of Siemens workers at the cost of Czech workers I presume.
Andrew said on August 26, 2014 at 7:05 am
“If we were being asked to fund ONE pilot windmill so they can experiment with bearings, I’d grumble and say “why doesn’t GE fund their pilot plant.” But I MIGHT acknowledge a potential public interest in funding research.”
And this is precisely the point that the greens do not want to admit: most green technologies are not yet proven to the point that life-cycle costs are known. Yet they want to place unproven technologies into mass production anyway.
I will once again restate to obvious (to anyone who has a rudimentary education and an open mind). If the present value of the energy generated (less the present value of all costs, including maintenance, transmission, buffering and backup) is less than the present value of all future energy derived, then any such project amounts to a destruction of wealth.
Without vastly increasing the price of energy, almost all solar and wind projects fall under this category. Given that fact, perhaps prototypes and testing may be justified, but wholesale production amounts to nothing less than the steady institutionalized deconstruction of a society that took generations of hard work and sacrifice to build.
This story fits well with the nuclear industry cost overruns with rate payers as the patsies and long-term waste handling costs of nuclear with and without the Yucca Mountain disposal site. Have they checked the O-rings?
@ur momisugly Chris4692 –
Picture the wailing and gnashing of teeth that would result from one out of every 1,666 cars on the road catching fire in its lifetime. We’d have every news outlet and opportunist politician calling for their immediate destruction.
@David L. Hagen
Well, sure, if the wind towers get the monitoring and maintenance cycle of a jet. When you look at the operating hours TBO & to mandatory retirement vs the Windmill required life cycle, and the additions to an already absurd cost benefit ratio for wind. it, pardon the expression, won’t fly.
Jets – High technology – high cost – high value – intensive use – profitable.
Windmills ? – ? – ? – ? – ?
When stuff only works when you abandon common business practice & common sense, then only politicians and zealots will support it.
Like so many proposed magin machines, everything will work perfectly if it can be made of unobtanium.
Having designed a heck of a lot of things with bearings in them over several decades I feel for the guys trying to solve this one. Just to help place the problem in context, here are few general problems with bearings:
They have far less resistance to impact/loading when they are not turning. This is not the lubrication problem mentioned above, that is additional. A gust of wind, especially on part of the blade, is a terrible thing to cope with even when turning.
The shafts are being twisted sideways and the comments about wind shear and inversions of direction are relevant (because the diameter is so large relative to the centre height). If the main shaft has a constantly higher torque ‘back’ at the top compared with the bottom, it bends the main shaft down in the centre enough to stress the bearings ‘sideways’, even though the average load is apparently within limits. Everything bends. A huge stationary gas turbine main shaft will bend permanently if it left sitting still for more than a month.
Usually the wind is speediest higher off the ground. The blades reach the top one by one and have maximum torque at that point (only) so the power delivered is far from smooth. It is three-jerks-per-turn with the peak torque applied when the tip is at the top. This is very similar to the problem faced by Darius Rotor designers. The torque applied to the main shaft goes from zero to massive to zero in 90 degrees, followed by a second burst, both from one blade (assuming there are two) while the other coasts. Then the other blade does the same things as it rotates into the wind. The stresses on the root of the blade are huge and early ‘egg beaters’ flew to pieces, broken at the root of the blade. The Canadian NRC tried diagonal bracing as can be seen in the 4 MW versions from the 70’s in Miquelon. My point is that gear-up boxes and bearings hate being pulsed. The pattern of wear shows up in the outer race as sort-of-dents (waves) which then start hammering the balls or rollers to death. Given the number of blades, the gear ratios and the bearing dimensions, you can calculate how many dents there will be in the circumference of the bearing.
The lower blade passes the tower and there is always a disturbance in The Force when it does because the tower disrupts airflow. This adds a beat frequency to the main shaft. It happens when the effect at the top is not taking place. Egad, it is a mess.
I think the axial fracturing is plain overloading while running. It creates a loose bar through the centre of the rollers.
These things are just too big for the materials available. Small mills work fine for decades. Basically they are saying that if they put in bearings big enough to work properly, they absorb too much energy. How much energy is ‘absorbed’ by each failure? The technology is being rolled out before it has been perfected and it is going to kill the industry. I happen to like wind generators – they have a place, like islands – but this is stupid.
Here’s why you don’t renewables: The cost of decarbonizing with wind power is about $100 trillion for the world.
http://www.paulchefurka.ca/Decarbonizing.html
This problem cannot be a surprise as any engineer worth his salt could predict it.
Part of the bearing problem, is blade fatigue and failure. I noticed a small wind farm yesterday, with three partly bladeless turbines (birdstrikes, hail, general fatigue??). But if turbines are shedding bits of blade, that puts a huge stress on the bearing, until the thing can be feathered and braked to a halt.
Do turbines stop automatically, if they detect too much vibration, or does it have to be done manually? If the latter, then a great deal of mechanical damage will be done before the thing is brought to a halt.
Ralph
Question for BJ Hanssen :
What are these “oil company subsidies” you speak of? How can an industry that is hugely taxed, be also subsidized to a meaningful degree?
I tried searching the web for descriptions of these “subsidies” and all I found was lists of nonsense saying that oil companies are subsidized because?:
– They are allowed to use public roads
– They are taxed on net profit, rather than gross? They are allowed to deduct business expenses before paying taxes? every other business does that, you know.
– the “externalities” – but since everyone benefits from the use of fuels, WE are the cause of those “externalities”, not the oil company.
The amounts claimed to be subsidized are pretty ridiculous, “Oil co. subsidies” are an often used argument in favor of subsidized stupidity, it would seem like someone would publish a credible list?</b?
I’ve been hearing of ceramic bearings replacing steel in some applications – high end bicycle wheels for example. I wonder why this is not a problem in things like steam generators? Is it the weight of the blades on the wind turbin?
Chris 4692 says ..”but it remains that wind power is a technically viable energy source.” This I am sorry to say is not a very useful statement. Everything is technically viable at a cost unless there is an attempt to break the physical laws of nature which means it simply cannot be done. Viability is a function of context and in our world that includes economics.
@ur momisugly Jim G –
Any engineer worth his salt could indeed predict this.
The problem is that the engineer would get overruled by the manager who is only concerned with the subsidies padding the bottom line for long enough for him to grab the cash and get away.
Dave Ward mentioned the problems of vibration and this seems to be what is killing wind turbine bearings.
Not only are the aerodynamic stresses of changing wind speeds and directions large but its now becoming apparent that damage to the rotor leading edges in service cause not only a loss of efficiency but out of balance forces that can quickly become very damaging. In large turbines we are talking about long (100m) wings that are very lightweight and slender. All it takes is a small nick in the aerofoil to produce less lift in one blade. That can cause heavy vibrations in the bearing and lead to premature failure. Such nicks are hard to spot and treat being tens of metres off the ground.Icing can also cause such problems especially when the blades start shedding ice.
These vibrations are also often the source of the complaints of noise and disturbed sleep patterns from people near large turbine installations
Fact is, if the wind farm industry had to do a real EIS, they wouldn’t be allowed to build.
BJ Hanssen (@BJHanssen) August 26, 2014 at 3:54 am
Even if you are not an AGW believer, I don’t understand why you would be against developing renewables.
_________________________
Because they do not work, and their intermittency will bring any nation to its knees. You cannot run a 24/7 society in intermittent power, and there is no feasible storage system, without using fossil fuel backup on spinning reserve. See this analysis, written in 2004.
http://wattsupwiththat.com/2009/05/25/renewable-energy-–-our-downfall
If you want to destroy the economy of a nation, and thereby destroy the wealth and living standards of its people, then please do campaign for renewables. But if you have the slightest concern and regard for the future of your children, then I might suggest you look at nuclear fusion and/or nuclear LFTR.
Ralph
@ur momisugly Tilo –
The problem is the sheer size of the components involved. When you’re talking about a bicycle wheel bearing with a shaft diameter of maybe a centimeter, it’s a completely different animal than a wind turbine with a shaft maybe 200 times bigger. The production methods just don’t scale.