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Identifiable decline

Readers will no doubt recall the study by Gordon Hughes, which suggested that wind farms are wearing out much more quickly than previously thought. This was the subject of a bit of to and fro at BH the other day, when Prof David Mackay, the chief scientist at DECC, appeared in the comments to dispute the findings. There were some further developments at around the same time, which I have been meaning to post since before Christmas.

At around the same time he appeared in the comments at BH, Prof Mackay published a more detailed rebuttal of Hughes at his own blog, which he said showed that Hughes' results were spurious. Hughes' model has parameters for the age-related performance of the wind farm, one for the windiness of the place in which it is located, and another to relate its performance to other windfarms. Mackay's case is that Hughes' model is non-identifiable, which means that the fit to the data is arbitrary: Hughes could, according to Mackay, explain the data say with a fast decline in performance and an increase or windiness, but could also do it with a slow decline in performance and a decrease in windiness. This point was disputed by Hughes.

The following day the Renewable Energy Foundation published some background, explaining that the two sides had in fact been discussing the issue since the original Hughes paper appeared in 2012. Hughes had apparently met with Mackay and had at that time apparently persuaded him that the model was in fact identifiable. Mackay had then shifted position somewhat, claiming only that the decline in performance was overstated (he suggested 2% per annum compared to Hughes' 5%). However, by May Mackay had apparently reverted to his earlier position, namely that Hughes' model was non-identifiable.

The REF's summary of the story to date ended with this strikingly robust statement:

Professor Mackay has made considerable efforts, first to persuade us to withdraw Professor Hughes’ paper, and now publicly, and on dubious grounds, to discredit work which is obviously original and draws attention to a previously undiscussed phenomenon, the decline in load factor over time, that was not acknowledged, for example, in the Department of Energy and Climate Change’s own levelised cost estimates for wind power. This is extraordinary behaviour for a Chief Scientific Advisor to government. Rather than shooting the messenger, Professor Mackay might more fruitfully be advising government on how best to ensure that consumer gets better value for their subsidy, and that we present a more economically compelling example of the low carbon economy to the developing world. 

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Reader Comments (59)

Caught between the science and politics - a government advisor will always choose the politics.

After all it is the public that picks up the bill when things go badly wrong!

This reminds me of the temperature pause -
pause what pause?
there is no pause!
the warming is still there but natural variability is hidding the rise!
yes there is a pause but tthe temperature will rise rapidly soon!
the pause doesn't meaning anything if the period is less than 17 years!
It is still warming in the deep ocean we just can't see it!
we need 30-50 years to determine whether the pause is real!
blah blah

Jan 15, 2014 at 11:48 AM | Unregistered CommenterCharmingQuark


"Professor Mackay has made considerable efforts, first to persuade us to withdraw Professor Hughes’ paper, and now publicly, and on dubious grounds, to discredit work..................................."

Now I wonder where he got that idea from?

But putting sarcasm aside - a) Well done the REF and b) Ouch! Prof Mackay has just GOT to be smarting from that justly deserved put down - and WHAT a put down it is!!

"Professor Mackay might more fruitfully be advising government on how best to ensure that consumer gets better value........................."

Wise words there indeed.

Will the rest of the charlatans heed them tho?

Jan 15, 2014 at 11:54 AM | Unregistered CommenterDoug UK

There is no decline there. Go read the story of the 1st Viscount Cherwell,_1st_Viscount_Cherwell

Like with IT projects, politicians are at an absolute loss regarding science, and consistently get advice from a peculiar set of chosen people.

Jan 15, 2014 at 11:57 AM | Registered Commenteromnologos

Get that right up you, Mackay!

Jan 15, 2014 at 12:04 PM | Unregistered CommenterBig Malky

Of course, in the real world, it is the operators who would be taking the risk of loss of shorter life and loss of efficiency (or getting the benefit of longer life).

It is only in the twilight world of government and subsidies that a "Mackay" would have any relevance at all.

It is simple - let the market decide.

Meanwhile, it seems that our our wind power is amongst the dearest in the world, according to a DECC report carefully hidden away.

Jan 15, 2014 at 12:15 PM | Unregistered CommenterPaul Homewood

Would it save everyone a lot of time if I blamed carbon dioxide and global warming for any potential increase in wind-turbine failure rates?

More seriously, I would have thought that mechanical/electrical engineers would be used to doing these types of analyses in their sleep. But how does either side get full access to the required data? Much of the information is probably proprietary to the manufacturer/maintenance servicer/grid operator, no?

Jan 15, 2014 at 12:24 PM | Unregistered Commentermichaelhart

Not more models! Surely, whether these things wear out and need fixing or replacing is an empirical question.

Don't any scientists do real data anymore?

Jan 15, 2014 at 12:24 PM | Unregistered CommenterMax Roberts

And rthe position with regard to off-shore windfarms will be even worse, as anyone who has experience in the maritime, shipping, off-shore industries will know. Both the harshness of the maritime environment, and the difficulties that that environment presents to effecting maintenance has been under-estimated.

All very reckless. And to make matters worse, windfarms do not even achieve the goal of reducing CO2 emissions because of the need for backup from fossil fuel power generation. What a fiasco!!

Jan 15, 2014 at 12:26 PM | Unregistered Commenterrichard verney

"whether these things wear out"

Of course not! It's just a flesh wound...

Jan 15, 2014 at 12:58 PM | Unregistered CommenterJames P

I spent 35 years in mostly heavy engineering and for mechanical moving parts the engineers would set a design criterium for the life, being it years or hours of work or whatever criterium would apply and they would test critical parts to make sure they complied. I am 99.99% sure that the manufacturers of wind turbines have such design criteria for all installed parts and maintain records of failure in order to improve on the working life of the parts. Enough wind turbines have been working in quantity made by large suppliers such as Vestas in Denmark and Siemens Germany for them to gather sufficient performance information to confirm or invalidate Professor Hughes' findings. The fact that they have not, would indicate that the actual world more closely mirror Professor Hughes' findings than the position of Professor Mackay. Unfortunately we cannot launch a FOI request against foreign suppliers but I wonder if DECC are "hiding" this kind of information. If not, why have they not demanded this kind of information from the major suppliers. That would also have enabled Professor Mackay to provide a more fact based contribution.

Jan 15, 2014 at 12:59 PM | Unregistered CommenterJohn Peter

Charming Quark

It is not a pause, it is a stop
It can only be a pause if you know the temperature is going to continue rising and nobody knows that.

Jan 15, 2014 at 1:05 PM | Unregistered CommenterRoger Tolson

So, we have an academic applying pressure to have a paper withdrawn. In 2012.

But, weren't we assured that such practices when they appeared in the Climategate emails were untypical and abhorrent to all academics moveonnothingtoseehere?

Jan 15, 2014 at 1:09 PM | Unregistered CommenterNW

McKay and his dept. often make heroic, unjustifiable assumptions. Witness the concept of negawatts via cost savings that studiously ignore installation costs of the new equipment required for them. Or his assumption that heating your home via a heat pump (in Winter fer gawds sake) returns a dubious 130% (after ignoring installation costs again) which would be better than just burning the gas at 90% efficiency. This latter fantasy was contradicted by the National grid in their report about biogas from sewage (available on their website) yet it forms the basis of one of his many dogmata. Excuse me but if, a) your assumptions are patently absurd and b) you deliberately exclude setup costs then it IS all hot air.

Jan 15, 2014 at 1:13 PM | Unregistered CommenterJamesG

Sooo atypical, although sanctioned at the highest level yet again. Burn those books...

Jan 15, 2014 at 1:16 PM | Registered Commenterflaxdoctor

Jan 15, 2014 at 1:05 PM Roger Tolson


"Pause" implies knowledge that warming will recommence - just a guess despite 'climate science' claims to knowledge of what the climate will do in the future: What Happened to Global Warming? Scientists Say Just Wait a Bit

Use of the word 'pause' is AGW believer spin.

Let's call it what it is. stop/cessation/halt - take your pick.

Jan 15, 2014 at 1:18 PM | Registered CommenterMartin A

All the components will have a design life and details would have been passed on to DECC. The windmills will also have a warrantee, so can we have our money back please?

Jan 15, 2014 at 1:19 PM | Registered Commentermangochutney

John Peter Wrote

"I spent 35 years in mostly heavy engineering and for mechanical moving parts the engineers would set a design criterium for the life, being it years or hours of work or whatever criterium would apply and they would test critical parts to make sure they complied. I am 99.99% sure that the manufacturers of wind turbines have such design criteria for all installed parts and maintain records of failure in order to improve on the working life of the parts."

I too am sure that the engineers would have such design criteria however I am less sure they maintain records of failure. They probably have records for failures in the warranty period but beyond that I doubt anybody but the operator logs it. The real problem seems to be that wind turbine blades are large and relatively fragile and even minor damage from hail or bird strike can disrupt the dynamic balance and/or aerodynamic efficiency. We are dealing with lightweight composite airfoils up to 80 m long here. This can lead to vibration which in turn may rapidly cause bearing failures.

Jan 15, 2014 at 1:19 PM | Unregistered CommenterKeith W

You always read the instantaneous output. Never the use. So you read that output from wind was 8% of production. Yes, maybe it was for an hour or a day. How much of it was used? How much of a reduction did that make in conventional output or fuel consumption?

The problem is, we are making it when it is not needed and sometimes when it is positively harmful to the network, and then claiming this is a wonderful thing.

Jan 15, 2014 at 1:24 PM | Unregistered Commentermichel

As a retired mechanical engineer who spent what is laughingly described as a 'career' trying to keep production machinery going in a warm, cosy, indoor environment, I have always felt that wind turbines stuck out in the North and Irish Seas do not stand a cat-in-hell's chance of lasting 25 years.
The Danish experience with their 'fleet' is, as I understand it, that their offshore turbines last 7-12 years. Now, our 'fleet' is newer (by a few years) - but unless someone tells me that major strides have been made to materials and rotating seals, while still being cost-effective, than I'm prepared to accept that 'ours' might last a bit longer.
However - a few points. Firstly, several major players have recentlybacked away from what are potentially lucrative offshore farms, given the ridiculous subsidies and 'feed in' tariffs which still apply to such projects. Secondly, as I understand it, several offshore wind farms have been 'sold on' to (e.g.) pension funds - so the promises originally made by the developers probably now mean diddley squat.
Finally - I read an article in my 'trade' journal (Professional Engineering) a few months ago, reporting on reseach carried out by the Emeritus Professor of Physics at Harvard, no less (and others) - which stated that, over time, the 'windiness' around a large wind farm actually decreases - due to an extension of the function known as 'wind shadow'.
I'm sure such findingws would be poo-pooed by the likes of McKay because they don't fit the perceived wisdom. Well, as they say in Devon where I used to live: 'Us'll see, won' us...'

Jan 15, 2014 at 1:50 PM | Unregistered CommenterSherlock1

Completely Off Topic, but I just had to share.

A total hissy fit melt down from Corinne Le Quéré from the University of East Anglia (that "esteemed" institution) published on the Telegraph web site.

What an embarassment. Was there nobody there willing to save that woman from herself?

Jan 15, 2014 at 1:55 PM | Unregistered CommenterGeckko

Even if windmills were as reliable as Prof. MacKay and DECC would like to believe, they are still a hopeless way to try to generate electricity on a large scale. Their energy density is a joke, as MacKay explains this in his book Without Hot Air, page 32. This graphic from a BH post a few months back also so spells out the futility of wind, which (in Hanover) needs an area of 25km2 to generate 300MW.

Source page - Energy Impact

Jan 15, 2014 at 2:07 PM | Registered Commenterlapogus

Martin A: "stop/cessation/halt..." Peak?

Jan 15, 2014 at 2:25 PM | Unregistered CommenterHarry Passfield

I continue to use Gordon Hughes' results in evidence at public inquiries and the like. I looked at his work and that of MacKay (draft6, so still not final) and accepted that Hughes had correctly modelled the changing wind from year to year (huge variability). I note that wiond farm operators love to sell their wind farms on to gullible investors befotre they start to wear significantly (geraboxes and bearings are knackered after a few years). I suspect the increased wear of offshore turbines may be the reason developers are now pulling out - they are beginning to see the effect of wear. Fortunately it is not the electricity consumers who bear the cost of the wear and tear. In fact we are better off, the quicker they wear and produce less electricity.

It is all not surprising, when you consider a turbo-generator in a power station operating under carefully controlled conditions and subject to regular maintenance and compare it with a wind turbine operating under the most harsh and erratic conditions where maintenance is virtually impossible, that wind turbines have a very short and unproductive lifetime.

Jan 15, 2014 at 2:47 PM | Registered CommenterPhillip Bratby

From Geckko's link

"If Mr Thomas would like to improve upon his fictional writing, my university, the University of East Anglia, has an esteemed creative writing programme, though he’ll have to do better than this to win a place. "
Corinne Le Quéré is professor of climate change science and policy at the University of East Anglia

Yes Corinne the UEA has a creative wring programme it is called Climate "Science"

Jan 15, 2014 at 2:51 PM | Unregistered CommenterCharmingQuark

Once again, they, we're arguing the toss about the arrangement and alignment of deckchairs on the upper deck - as the big ship slowly disappears, sliding, foundered and sinking into the vast blue briny.

Jan 15, 2014 at 2:56 PM | Unregistered CommenterAthelstan.

The REF are to be commended for their response to Professor Mackay.

"Professor Mackay has made considerable efforts, first to persuade us to withdraw Professor Hughes’ paper, and now publicly, and on dubious grounds, to discredit work which is obviously original and draws attention to a previously undiscussed phenomenon"
Mackay obviously tried to persuade the REF privately.
Same stable as Phil Jones if you ask me.

Jan 15, 2014 at 3:05 PM | Unregistered Commenterpesadia

Peak? Jan 15, 2014 at 2:25 PM Harry Passfield

No I don't think so - like 'pause' that too would imply knowledge of what lies in the future.

Jan 15, 2014 at 3:09 PM | Registered CommenterMartin A

Pause? Peak? Climate and pause added together?

We have had the following evolution - CAGW => global warming => climate change => climate disruption => climate weirding => climate extremes

perhaps the next manifestation will be climate menopause

I think we should ask the esteemed creative writng department of the UEA! Calling Prof Phil Jones

Jan 15, 2014 at 3:16 PM | Unregistered CommenterCharmingQuark

Chief government advisor Mackay's clandestine machinations exposed.

Jan 15, 2014 at 3:34 PM | Unregistered CommenterZT

CharminqQuark - if I may be permitted to add to your suggestion:

CAGW => global warming => climate change => climate disruption => climate weirding => climate extremes => Global Bollocks

Jan 15, 2014 at 3:47 PM | Registered Commenterlapogus

I said at the time that NacKay's paper first came to light, that it was strange that DECC's Chief Scintific Advisor would deem it necessary to do his own analysis of the data. With thousands of top-notch scientists, engineers and statisticains in DECC at his beck and call, why couldn't he get them to do the analysis? Perhaps I'm misunderstanding the quality and capability of the civil servants in DECC. They get paid enough to be top-notch, and they don't seem to do anything useful most of the time.

Jan 15, 2014 at 3:50 PM | Registered CommenterPhillip Bratby

From the REF report
"The idea that the performance of wind farms declines with age is regarded as perfectly normal by academic and other independent engineers. It is true for other electro-mechanical equipment subject to large stresses, so why would wind turbines be any different?"

Why indeed?

Possibly because they are powered by politicians' hot air?

Jan 15, 2014 at 3:56 PM | Unregistered CommenterDon Keiller

Even if MacKay is right, and the results could, perhaps, be explained by a decrease in windiness, it simply hasn't happened.

I am in the middle of a study of European wind data between the years 2005 to 2013 (across 43 sites, using half-hourly samples) and that suggests that there has been no such decrease. 2010 was rather poor across the UK, but later years have been back to the previous norm. So MacKay has no hope of success on that tack.

Jan 15, 2014 at 4:00 PM | Unregistered CommenterCapell

I vote for climate menopause. Thanks Charm.

Jan 15, 2014 at 4:18 PM | Registered CommenterRichard Drake

When Mackay's name crops up - I like to repost a reminder of his earlier life as a political activist, apologies to those who've seen it:-

It's quite instructive to do a little background research on Prof David MacKay, the author of this "calculator" and Chief Scientific Adviser to DECC.

MacKay is a physicist and mathematician who has enjoyed a stellar international career in fields involving neural networks and artificial intelligence.

He says he first became interested in climate change and renewable energy about five years ago and he was appointed as chief adviser to DECC in 2009.

On his personal website, he makes the intriguing comment - "Civil servants aren't permitted to be politically active, so I have removed my political links from this website".

Judicious use of the "Wayback Machine" reveals all, however:-

Prof MacKay is apparently a man of strong opinions and he has lent his weight to a number of political campaigns over the years:-

He hates cars and supports "any organizations that agree that cars stink".

He is a campaigning cyclist.

He campaigns for the anti-smoking fascists ASH

He helped lead a campaign against the conviction of two social workers who allowed open heroin dealing in the care facility they were responsible for.

After 9/11. he campaigned against the US invasion of Afghanistan and Iraq, illustrating his website with an anti-war quote from Tony Benn, an (inaccurate) allegation that the west supplied WMD to Saddam - and a curious cartoon showing Jesus beating up George W Bush.

Of course, MacKay is as entitled to his political opinions as the next man (and Geoff Chambers may soon be breathing down my neck for turning this into a left v right issue) but I do find it extraordinary that every time we scratch the surface of the "great & the good" who are leading us to the green paradise that awaits - we find the same tired old lefties we thought we'd left behind with the collapse of the Soviets in 1989.

Can we be sure that Prof M's rather extreme left wing opinions don't influence his role in planning all our future lifestyles?

Dec 30, 2011 at 9:00 PM | Foxgoose

Jan 15, 2014 at 4:25 PM | Registered CommenterFoxgoose

Jan 15, 2014 at 3:16 PM | Unregistered CommenterCharmingQuark


Jan 15, 2014 at 4:38 PM | Unregistered CommenterHenry Galt

Wind farms decline in efficiency at a rate between 2% and 5% per year.

On its own this is not particularly useful. How does it compare with the effect of ageing on other types of power generation?

Jan 15, 2014 at 4:49 PM | Unregistered CommenterEntropic man

There is this:

Are global wind power resource estimates overstated?
Amanda S Adams and David W Keith

which suggests that turbines interfere with each other as wind farm deployment increases, reducing output below design assumptions by 25-50%

Jan 15, 2014 at 4:57 PM | Unregistered CommenterIt doesn't add up...

For many years, I kept a power boat on a sheltered estuary mooring for 12 months of the year.

Anyone who has had to maintain machinery permanently exposed to the marine environment knows that even materials chosen to resist it - like stainless steels, epoxy finishes, polycarbonate plastics etc etc suffer continual degradation.

Look at the state of any commercial ship when it docks for periodic maintenance.

IMHO after a decade or so the maintenance requirement for offshore wind farms will become insupportable.

Jan 15, 2014 at 5:02 PM | Registered CommenterFoxgoose

Pedants corner: It's David MacKay, not Mackay, and he's an Adviser of the Chief Scientific sort, not an Advisor. But these are small faults on the part of the Renewable Energy Foundation in the light of their excellent piece.

Jan 15, 2014 at 5:10 PM | Registered CommenterRichard Drake

According to Wikipedia, the Renewable Energy Foundation was founded by Noel Edmonds. Can that possibly be true?

Jan 15, 2014 at 5:12 PM | Unregistered CommenterJames Evans

A number of years ago I looked at output from The Arklow Bank for the years 2007 and 2010. After adjusting the output for the low winds in 2010 I came to the conclusion that based on this data wind turbines had an economic live of 10 years or so.
Subsequently having looked at output from Danish Data I have come across evidence that output from wind turbines can drop dramatically after 10 years operation. If you track forecast versus actual output on Eirgrid web site you will frequently observe a 250+ mega watt difference between forecast output and actual. You will notice this particularly where the forecast is 1500 + megawatts of output . As the wind capacity currently installed in Ireland, Republic of, is some where around 2200 megawatts you can conclude that approximately 10% or so of current capacity needs to be replaced if the 37% target, of total electricity output, for wind generation is to be achieved. This would seem to be conclusive proof that output declines as Professor Hughes has discovered are accurate. This decline in actual output versus forecast should increase over time.

Jan 15, 2014 at 6:13 PM | Unregistered CommenterSean O'Dubhlaoigh

Forget about warranties. In recent years civil servants have thought themselves very clever by writing supposedly watertight contracts for big projects, putting all liabilities and costs on the contractor. Of course only an idiot would accept such a deal which is why if you look closely at the signboards adorning such projects you will observe that while the name of the organisation responsible may include the names of large companies, the legal entity concerned is not those companies but an entity created by them for the project. In the event of major liability, this entity will not exist in any useful form.

Jan 15, 2014 at 6:27 PM | Unregistered CommenterNW

Hughes could, according to Mackay, explain the data say with a fast decline in performance and an increase or windiness, but could also do it with a slow decline in performance and a decrease in windiness.

But, surely, we have enough sensor based information to distinguish one from the other? Has there been an actual increase or decrease in 'windiness' over some generally accepted period? No? Then we can look to 'performance degradation' beyond what was initially set out.

Perhaps we should, via some completely HMG funded 'experiment', have built a wind farm (back in 90) in an optimal place and run the thing for a few years before embarking on an 'all out assault'. Such an 'experiment' would have identified the problems in addition to the benefits.

So, here we are realising that 'wind' might not be the 'panacea' it sounded like back 'in the day'. Any half decent Engineer could have warned you back then that this would happen without some 'experimentation'.

We hand the future of "The UK" over to some dreamer, with a first class honours from ox-bridge in 'classical studies', and then wonder why it's all now going wrong.

If one had asked the right people initially then it wouldn't be going wrong. Let 'Baroness Chaos' design your future and you get, well, chaos. Simple really.

Jan 15, 2014 at 6:40 PM | Registered Commenterbh3x2

12:59 PM John Peter

Offshore windmills with a 25 year life? As an intermittent visitor to offshore engineering facilities in many countries (inc. North Sea ) and designing / maintaining equipment in that environment - there's only one word that comes to mind - boll***s.

As to the design criteria = since these items are way too big to be actually tested in a controlled way at a full scale - the deployment is the test. As I understand it there is a significant debate going on in windmill engineering about why they're seeing the quantity of "premature" failures particularly of gearboxes that they *are* seeing. Corrosion issues are apparently being hidden too - the PR departments of the offshore wind crew must be constantly playing "whack a mole" with personal blogs.

MacKay is simply spinning a line and from the biog details offered above his motivation in that endeavor is transparent - his assertions, without empirical evidence from the manufacturers are plainly mendacious.

Jan 15, 2014 at 6:46 PM | Registered Commentertomo

One has to admire a climate activist complaining about a model's lack of variable separation!

Has MacKay explored the exciting world of Mannian statistics?

No doubt the papers that MacKay makes considerable secret efforts to prevent depend on what produces the maximum benefit for MacKay. This is my model for MacKay's actions - and it seems irrefutable.

Jan 15, 2014 at 7:44 PM | Unregistered CommenterZT

Oh bh3x2 you've gone and made me watch another Bryony video, I've only just recovered from that last car crash one.

In this one she actually explains how Friends of the Earth and her team of lawyers "outwit" the Treasury and Business to push through the Climate legislation to "do the right thing". At least she's honest.

I've come across deluded airheads like this before convinced of their own superiority, but usually in fairly harmless roles. How on earth did Bryony get to be pulling the levers of power? A sad indictment of our supposed meritocracy.

Jan 15, 2014 at 7:57 PM | Registered CommenterSimonW

"How on earth did Bryony get to be pulling the levers of power?"

Ed Miliband thinks she's clever.

You should forward the youtube address to HM Treasury and Peter Lilley.

Jan 15, 2014 at 8:13 PM | Unregistered Commentergeronimo

They're not "wind farms" they only farm taxpayer wallets.

Jan 15, 2014 at 9:18 PM | Unregistered CommenterAC1

@ AC1

They're "Subsidy Farms"; that's what they harvest.

Jan 15, 2014 at 9:53 PM | Unregistered CommenterJoe Public

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