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Behind the windfarm scenes

Readers may remember Gordon Hughes' report about the lifetimes of real-world industrial wind turbines and the finding that this is much shorter than assumed in government cost projections. The reasons for the short lifetimes centre on wear and tear on the turbine blades and on the gearboxes.

In that vein, you may be interested in this recording from a forum for windfarm operators in which some of these problems are discussed in fairly plain terms. Having listened, you realise that the factors affecting performance are legion, including not only wear and tear, but dirt build-up on the blades, icing. These factors can severely impact upon performance, and because they tend to unbalance the blades they then increase wear and tear on the mechanical parts of the turbine. But icing is even more serious, as the last speaker on the recording notes:

The icing issue in Northern Europe is huge...there was a [wind] park in Northern Sweden...and it iced up for 21 are talking about a complete the maths...everything else becomes insignificant...there will be huge PR are looking at if we will invest in wind farms or wind energy ever again.

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Reader Comments (71)

Well there's a surprise!

Nov 26, 2013 at 9:11 AM | Unregistered Commentergeronimo

RWE axes Bristol Channel wind farm project - “It was made on purely technical grounds and reflects the many complex challenges of constructing offshore wind farms,”

Nov 26, 2013 at 9:25 AM | Unregistered CommenterTinyCO2

I noticed the MSM were very quiet in the reporting of the two maintenance engineers who died recently when the wind turbine they were working on in Holland caught fire. The escape route was cut off by the fire and one fell, or jumped, to his death, and the other was found burned to death inside the turbine.

Nov 26, 2013 at 9:25 AM | Unregistered CommenterBruce

Designing turbine blades is a challenge in its own right, given all the competing needs and thus compromises made: aerodynamic efficiency, strength, weight, weight distribution, stiffness etc. Manufacturing the blades is a very complex process. Operating the blades under rapidly varying stresses and loadings in a variety of atmospheric and corrosive conditions is bound to lead to rapid degradation of their performance and physical condition. Couple this with the varying loads on the shaft, gearbox (if it has one) and generator and you have real problems of wear and tear. Then try and carry out maintenance 100m up in the air and miles offshore and you have an impossible situation.

Contrast the situation with a turbo-generator in a proper power station, where the flow of the working fluid is carefully controlled. For maintenance, there are overhead cranes and laydown areas. A turbine can be removed, replaced by a refurbished one, rebalanced and back in operation good as new in a matter of days.

No sane engineer would contemplate wind as a means of generating massive amounts of electricity - wind turbines are the result of political decisons based on a complete lack of technical knowledge.

Nov 26, 2013 at 9:25 AM | Registered CommenterPhillip Bratby

They are planning / hoping to build 70-Plus 600-foot-tall turbines around us, here on the shores of Lake Erie, Niagara Peninsula. There are already scores of them up an hour west of us....

Our area is subject to high winds at least a dozen times a year, each bout running 2-3 days, sometimes up to 100k. And while those turbines are not in our face yet (6 of them will be within 2000 meters), we are experiencing a very messy winter, and sure to have more of those in the future. So we will get tons of Ugly standing around doing nothing- aside from the ecologic, economic and health damage.

We're in a lawsuit to stop them, but...

Nov 26, 2013 at 9:25 AM | Unregistered CommenterOtter

We need build turbines where the weather is mild and the winds gentle. Who's ever going to need energy when it's cold and stormy?

Nov 26, 2013 at 9:27 AM | Registered Commenteromnologos

A relative of a friend said that he feared he might drown trying to get onto offshore towers.

Nov 26, 2013 at 9:32 AM | Unregistered CommenterTinyCO2

Re: TinyCO2

> “It was made on purely technical grounds and reflects the many complex challenges of constructing offshore wind farms,”

The BBC version says the following:

But BBC South West political editor Martyn Oates said: "Sources have told us that this will not go ahead because of problems in financing it.

"Just last week, [green energy group] Regen SW said that the government's recent announcement that it is going to cut back on green levies to support renewable energy was already undermining investment in the region and putting jobs at risk.

Followed by a section from FoE about "Anti-green ideology". No bias or slant there at all.

Nov 26, 2013 at 9:38 AM | Unregistered CommenterTerryS

There is a pub near where I live called The White Elephant.

Nov 26, 2013 at 9:41 AM | Unregistered Commentermichael hart

Freezing cold here this week with no wind, how do I get power?

Nov 26, 2013 at 9:42 AM | Unregistered CommenterDoug Elliot


the two reasons are probably both true. If someone offers enough money then many things are viable. Clearly some insane things are less expensive than others.

Nov 26, 2013 at 9:51 AM | Unregistered CommenterTinyCO2

and well in Norway wind farm are designed with the hypothesis that ice will be likely to happen quite often.

what if and exceptional cold spell occured in a place where wind turbines where built without ice taken into account for cost issues?

such as for the electrical lines in france for instance it can be devastating.

Nov 26, 2013 at 9:56 AM | Unregistered Commenterlemiere

I suppose the technological sophistication of a wind turbine is about comparable to that of a bicycle.
You can buy a bike for forty quid, but if you want to win the Tour de France it’s going to cost you more like four thousand.

And you wouldn’t pull out of the Tour de France just because it’s a hundred times more expensive than pedalling to the shops, would you?

There you are then.

Nov 26, 2013 at 10:05 AM | Registered Commentergeoffchambers

Surely thanks to STOR when turbines stop generating and freeze up we can thaw them with electricity from Diesel generators ? Or failing that plant a dozen of those green-bating patio heaters underneath each one...

Nov 26, 2013 at 10:16 AM | Unregistered CommenterMorph

Phillip Bratby -

No sane engineer would contemplate wind as a means of generating massive amounts of electricity - wind turbines are the result of political decisons based on a complete lack of technical knowledge.

Spot on. My father (40 years in NOSHEB/SSE) usually laughed when people suggested wind as a way to make large scale electricity. But then supermarket managers took over (just as they did in the banking profession) and now we are all paying for their stupidity.

Nov 26, 2013 at 10:19 AM | Registered Commenterlapogus

there will be huge PR problems...

Here we go again. Who needs reality?

Nov 26, 2013 at 10:23 AM | Unregistered CommenterAllan M

You might expect that, at an early stage of development, all sorts of problems will gradually be found. And as the technology matures, these problems will be addressed.

On the other hand, initial wind farms will be sited in the best locations, and later ones will have to put up with worse conditions, such as more variable wind.

Because of the politics, it is impossible to make a balanced technical judgement on the cost benefits of wind farms. And so sensible proposals are unable to be made, and sensible warnings will go unheeded....

Nov 26, 2013 at 10:29 AM | Unregistered CommenterDodgy Geezer

I understand that one of the problems with these “daffymills” (h/t Fenbeagle – and, thence, Wordsworth) is ice throw. On a daffymill with 20 metre blades, the blade tips are travelling a little over 4.5 mph per rpm; I suspect (though have never measured) that these Uglies rotate at speeds greater than 1 rpm; assuming it is in the region of 10 rpm, then the tips are whizzing around at more than 45 mph. How large are the ice chunks thrown off these blades, how far would they go, and what damage could they do? All interesting questions that I have no doubt the politicos have not considered, and probably will never consider.

Nov 26, 2013 at 10:29 AM | Unregistered CommenterRadical Rodent

Radical Rodent

It's been reported on here:

Nov 26, 2013 at 10:36 AM | Unregistered CommenterJack Cowper

Radical Rodent. The speed of large turbines is usually about 20rpm, and thus the blade tips on large turbines are travelling at over 200mph. The ice usually forms when the blades are stationary, and may fly off when the turbine restarts, although a control system should stop the blades moving until they are in balance. It has been known for ice chunks to travel well over a 100metres. Death could be the result.

Nov 26, 2013 at 10:38 AM | Registered CommenterPhillip Bratby

Jack Cowper posted this at the foot of the recent Sound of the wind thread:

which highlighted the problem when a turbine was badly situated in a residential area near Truro - was this ice throw a one-off?

I suppose icing and ice-throw will be rare in Cornwall, but will be quite common in the intermediate and high level sites in the Highlands. Most windmills are in remote locations, but there are now quite a few close to existing forest tracks and paths where there is legal public access. SSE is very Health & Safety concious, and I noticed they have put general warming signs for the public at the usual entrance points to their Griffin windfarm in Highland Perthshire.

Nov 26, 2013 at 10:40 AM | Registered Commenterlapogus

I was under the impression that wind turbines actually draw energy off the national grid when it gets too cold to stop the gearboxes freezing up.

"During the winter, temperatures often fall below freezing where wind turbines are set up. When the oil in the gearbox freezes, it is hard to get the system running again after it has been motionless for some time. Therefore, heaters are often used to warm up the oil in the gearbox.

In addition, rotor blades are also heated to prevent them from icing over or being damaged by condensed water.

Finally, anemometers and weather vanes also have to be heated in cold regions to prevent them from malfunctioning and damaging the turbine."

Maybe we are using cheaper ones, still seems odd to me that they actually use power in the cold.

Nov 26, 2013 at 10:44 AM | Unregistered CommenterMike

In centuries to come anthropologists will uncover symmetric arrays of wind farm stumps all across northern Europe. These will be interpreted as some ancient religious symbols rather like those on Easter Island. They will make no other logical sense at all !

Nov 26, 2013 at 10:46 AM | Unregistered CommenterClive Best


The first incident I read about happend in Peterborough. A quick google search lead me to this:

Nov 26, 2013 at 10:47 AM | Unregistered CommenterJack Cowper

Why not just build a few hundred extra windmills to solely provide power to a warming system for the windmills that provide all the power?

This would work sure it will.....

Oh god, I've given them ideas now haven't I?

Nov 26, 2013 at 10:55 AM | Unregistered Commenterjones

The solution to the ice-throw issue is probably not as straight-forward as simply not starting the turbine if it has ice on the blades.
The aviation industry learnt the hard way that ice will form on aircraft propellers in flight so how will turbines cope with that? (I happened to hear an interview with a wartime meteorologist who mentioned ice hitting the fuselage of a Halifax). I guess it is a pressure/temperature effect caused by the blade passing through cold, moist air.
Heating such a large surface would drain a lot of the output - you'd end up with a giant fan heater! Oh no, more warming!

Nov 26, 2013 at 10:58 AM | Registered Commentermikeh

Or a couple of nuke plants perhaps?

Nov 26, 2013 at 11:01 AM | Unregistered Commenterjones

Re Accidents


(over 1400 now)


Nov 26, 2013 at 11:09 AM | Unregistered CommenterGRUMPY gRANDDAD

Phillip Bratby at 9:25 AM

I totally agree and:

"No sane engineer would contemplate wind as a means of generating massive amounts of electricity"

As an engineer who has grown more and more cynical, and I would like to think realistic over the decades, I really must agree with you. Taking any bit of modern equipment, putting it on a very tall pole and placing the lot on a remote hillside for years is a great way of assuring failure. Much better to have our generating capacity sitting under a nice roof with all the maintenance people and fitters in close attendance.

Nov 26, 2013 at 11:11 AM | Unregistered CommenterBlack Dog

What worries me is how the stresses on the blade due to ice are going to be caclulated .The blades on aircraft engines are relatively short . What would happen if their different masses of ice at different distances from the centre on different blades?

At heights of 100m, if the central column is damaged or there is fire how are people going to be safely evacuated?
If there are extremely windy periods after prolonged cold periods where temperatures are below -5C, the combination of thermal expansion and shear stresses could cause problems.

Nov 26, 2013 at 11:21 AM | Unregistered CommenterCharlie

@ Clive Best

Easter Island is probably the best exemplar we have of a public policy failure on the scale of the CAGW fiasco. AIUI the inhabitants used up all the timber on the island making rollers to move the carved heads from one place to another. When the crops failed one year they had no timber left to build boats and thus couldn't leave.

So they deliberately destroyed a key element of their economy with no forethought and no useful goal; they were simply trying to manage the sky.

Makes you think.

Nov 26, 2013 at 11:21 AM | Unregistered CommenterJustice4Rinka

Politicians are to be blamed if they wilfully refuse to consider expert counter-evidence when it is readily available.

'It must make sense - everyone's doing it.' Did you check to see the sense of it? Or did you simply regard the policy as bold, progressive and affording a regular flow of sound-bite and photo-shoot opportunities?

The policy certainly hasn't produced a regular flow of affordable electricity.

Nov 26, 2013 at 11:22 AM | Unregistered CommenterBob Layson

Here is a study on ice throw from a 50m (height) turbine with heated blades located in Switzerland. They found it could throw ice fragments in any season and they could weigh up to 1.8kg.

The formula they came up with for throwing distance is D*H*1.5 where D = rotor diameter and H = hub height.

Nov 26, 2013 at 11:23 AM | Unregistered CommenterTerryS

Geoff Chambers...............a competitive TDF race bike is a lot more than £4k mate.......more like £8k+. You could walk into a bikeshop yourself and get an off the peg bike for over £6k easy enough........yes that's right...for a pushbike. A time trial bike on the TDF would set you back maybe £12+.............

Anyway......back to windmills...

Nov 26, 2013 at 11:28 AM | Unregistered Commentermikef2

Bottomline : If there were no subsidies then the risk would be up to the investors who believe in it.
- when there are subsidies it ends up being a mess

Nov 26, 2013 at 11:48 AM | Registered Commenterstewgreen

radical, aren't blades heated so I've wouldn't build up on them (much like an aircrafts wings leading edges are heated)?



Nov 26, 2013 at 12:21 PM | Unregistered CommenterMailman

There is a supreme irony in windmills icing up...

Nov 26, 2013 at 12:26 PM | Unregistered CommenterJimmy Haigh

Nov 26, 2013 at 10:58 AM | mikeh
I remember flying Bristol-Edinburgh in a twin-prop in the early 90s, and the captain telling the passengers as we were over the Lake District that any thumps on the fuselage were caused by ice shed from the propellers.

Nov 26, 2013 at 12:28 PM | Unregistered CommenterDaveS

As I seriously looked at setting up a wind turbine maintenance company in Scotland and even went to visit an independent maintenance company called DMP in Denmark, none of this is a surprise.

The bigger surprise is that people get so focussed on aerodynamic efficiency when by far the biggest impact of efficiency is the downtime due to failing parts.

And it was because people in the UK obsessed with aerodynamic efficiency and not real performance in terms of overall reliability that we wasted some £50million on wind research for almost no net benefit.

Nov 26, 2013 at 12:39 PM | Registered CommenterMikeHaseler

And I've just remembered that one of my first jobs (University Holidays) was making blades - or at least making the collar around the base of the blade. it was a two person job, but I got in trouble doing a blade when the "trained" person went to the toilet.

Nov 26, 2013 at 12:43 PM | Registered CommenterMikeHaseler

Reliability is only a problem if the turbines need to work to make the operators money.

Many turbines will not be connected to the grid for 5 or more years but under the 'connect & manage' scheme operators will still be paid for fictitious output:

Nov 26, 2013 at 12:44 PM | Unregistered CommenterRobWansbeck

Re: mailman

The study I pointed to above was from a turbine with heated blades.

Icing is an important issue when operating wind turbines in elevated or arctic areas as it can cause significant production losses and represent a safety risk [1]. In 2004, a 600 kW Enercon E-40 wind turbine with integrated blade heating was installed on Gütsch mountain, central Switzerland, at 2'300 m asl. Coincidentally, a fully equipped test station of the Swiss meteorological network SwissMetNet was installed about 200 m away from the wind turbine in 2003 (Fig. 1).

Nov 26, 2013 at 12:55 PM | Unregistered CommenterTerryS

There were some very good reasons why wind energy was scrapped some several hundred years ago. It just took some medievelly minded idiots to try to bring it back 200 years later.

What goes around comes around !!

Nov 26, 2013 at 1:02 PM | Unregistered CommenterStephen Richards

The study I pointed to above was from a turbine with heated blades.

So where does the power come from to heat the blames ? Oooh I know, FOSSIL FUEL !

Nov 26, 2013 at 1:05 PM | Unregistered CommenterStephen Richards


"ice fragments"

Unfortunately, when you're out walking the dog and one skewers you through the heart, the evidence will just melt away!

Nov 26, 2013 at 1:13 PM | Registered Commenterjamesp

Having flown a microlight for many years I can attest to the importance of correct balance where propellers are concerned. Granted, mine was much smaller, and turned at considerably higher speeds, but even a small nick (such as would be caused by a stone being picked up from a runway), makes a hell of a difference. Those of us with 2 blade wooden props are also told to ensure they are left in the horizontal position when hangared, as this stops moisture from collecting in the lower blade. But even composite materials will absorb moisture. I did all my own maintenance, and could make comparisons with others who were less fastidious - simple matters like the life of rubber engine & exhaust mounts was a good indicator.

I also had to consider the risk of anything being thrown off the prop and damaging the wing fabric. Neither my aircraft (or me!) were designed for flight in icing conditions, but I wouldn't like to think of the temporary out-of-balance forces when ice build up is being removed by heating elements on the blades. Loss of even a part of a blade, let alone an entire one, can result in the immediate departure of the remains, AND the engine it was installed on! I'm sure there have been instances where the same thing caused a turbine tower to snap and collapse (IIRC there was one in Germany a year or so back?)

Nov 26, 2013 at 1:55 PM | Unregistered CommenterDave

Black Dog - as another engineer (but ALWAYS cynical) I couldn't agree more (I am ex-Hinkley Point 'A')... After that I spent much of what is laughingly described as a 'career' trying to keep high-speed medicines lines running, in a nice warm factory with a team of fitters at my beck and call - and that was - to use modern management-speak - 'challenging'...!
Nope - to stick rotating machinery 100 feet in the air, several miles out in the North/Irish/You Name It Sea and expecting it to last twentyfive years is - well, just crazy....

Nov 26, 2013 at 2:12 PM | Unregistered CommenterSherlock1

@Philip Bratby (and others)

...No sane engineer would contemplate wind as a means of generating massive amounts of electricity - wind turbines are the result of political decisons based on a complete lack of technical knowledge....

Actually, lots of quite sane engineers would, and do, contemplate, design, and build wind turbines. On their own, they present a lot of interesting technical challenges, which naturally attract engineers. I am sure that, given time and money, all these challenges can be overcome - they are not impossible to solve in principle.

The problem comes when you decide to make up whole wind farms and join them to the Grid. Wind energy is not dispatchable - it can't be guaranteed. So you have to have 'back-up' generators, and cycle these in and out depending on the wind output.

This means that your back-up generation has to be 'cycle-able'. Cycle-able generation runs at about 50% of the fuel efficiency of 'un-cycle-able' generation (generation optimised for long-term operation at a fixed output). So there's an immediate loss there. Worse, the process of cycling wastes fuel like there's no tomorrow. These are problems in principle - they can't be avoided.

It can be shown quite easily that adding wind-farms to a grid produces a net overall advantage initially, which then shrinks, and actually becomes NEGATIVE at a fairly early point. Assuming best possible circumstances, wind power could contribute 30% of a Grid's electricity before this happens. In worst circumstances, wind power goes negative at around 5%. A practical working figure for a real Grid might be between 10%-20%. The UK penetration is around 8% at the moment.

Note that this does not mean that you can't operate a Grid with wind power contributing 30% or above power. What it means is that such an operation would be running every single resource or operating parameter at a loss. It would be using more fuel, costing more money and generating more CO2 than a comparable fossil-fuel installation.

There would only be two reasons that I can think of for undertaking such a futile activity:

1 - Society is in the grip of a powerful mania which overcomes logical thought. This is not an uncommon trait in humanity - the South Sea Bubble and the Darien Scheme are two examples which spring to mind
2 - The people who decide on and commission wind farms are personally making fortunes out of them, and suppress all dissent.

Of course, there is no reason why the two reasons cannot be combined...

Nov 26, 2013 at 2:29 PM | Unregistered CommenterDodgy Geezer

wind turbines are the result of political decisons based on a complete lack of technical knowledge

I was amused a few years ago to hear the Danes describing wind power as "political electricity".

I find the technical challenges in all this stuff very interesting and try to attend the annual "renewables" conference in Aberdeen when I can.
You used to get some good engineers working in this sector in the heady early days, still do, but most of the Aberdeen-based ones have drifted back to the oil industry due to disillusionment and better pay.

It's clear from talking to any of them that they have massive technical and financial problems which might never be overcome but the press keeps talking it up as if it's all free , ready to go with just a little push and we could switch tomorrow if we wanted to. No wonder the public thinks there must be a conspiracy working against the 'Green' alternatives.

The cynical view, both within and without the renewables engineering crowd, is that the most valuable skill is writing grant applications.

Nov 26, 2013 at 2:33 PM | Unregistered Commenterkellydown


Unfortunately, when you're out walking the dog and one skewers you through the heart, the evidence will just melt away!
Do you know the Roald Dahl story of the woman who clubbed her husband to death with a frozen leg of lamb and then cooked the weapon and invited the investigating officers to lunch?

Nov 26, 2013 at 3:23 PM | Registered CommenterMike Jackson

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