Storms, Climate Change & an Economy of Truth.

You've heard the rhetoric. Global Warming/Climate Change/Climate Emergency is increasing severe weather events. There will be more storms. More destruction.

Statements like this from my friends in Greenpeace (of whom I have none) Link Here 

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“The frequency and strength of storms is increasing, leaving destruction in their wake.”

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Lurid stuff. Frightening even.

But is it true?

Is the frequency and strength of storms increasing?

The answer to that is No.

The frequency and strength of storms is not increasing. In fact for the last thirty years the average wind speed across large sections of the planet have been in decline, as have severe storm events. You can trace a slowing in global wind speeds right back to the 1960's.

From Antarctica right up to near the North Pole wind speeds have been going down.

I’ll concentrate here on the UK but this really is a global phenomena. (see references later)

Here is the frequency of high wind gusts events across the UK by year which the Met Office states they use as an indicator of "storminess".

Notice all gusts are in decline and that includes the extreme gusts that are supposed to be increasing. (MET office Data taken from Here)

Even though they have adopted a silly storm naming scheme (one suspects in order to add a little drama to otherwise common or garden weather events) the Met Office have come out and made clear that there is no link between Global Warming and UK storm frequency.

But they cannot quite bring themselves to reference their own data showing a slow decline in storminess since the 1990's. The Met Office webpage on Wind Storms is Here

The global slowing of wind speed is emphatic and serious enough to now be a research project for EU. (Here)

Even dear old Wikipedia has a (somewhat rudimentary) page on it Here

The best page is probably This Page from the Institute of Physics. (with caveats – see later)

Here’s a few more links that give useful insight into the phenomena.

ABC News Australia

Cosmo Magazine

Nature Magazine

So, while the panic laden Drama Queens in Greenpeace and Extinction Rebellion would like you to think that storms are dangerously increasing, actually the reverse is true.

Bad things always happen. There will always be storms. But today there are less of them and they are less potent.

But you will not hear anyone suggesting that this is a “good thing”.

Even the Phys.org article above struggled hard to find some bad outcomes yet failed to address any of the advantages of lower wind speed and less storms.

Yet when we look to (say) coastal defence, less storms mean coastal defence systems last longer. Less storms mean less storm surges. Less storms mean less wind damage. Less lost work days and less insurance claims.

The list goes on.

Even a merely lower average wind speed must result in less wear and tear on external structures. I am sure you can think a few more advantages of what is in essence more benign weather. 

By the way while the linked reports are all reasonably recent, this is far from new knowledge. Its just appears to have been kept pretty quiet until now.

It is interesting to note that while these reports all mention the possible ill affect on wind-turbines the reports make great efforts to (incorrectly) indicate that little is known about the wind speed at wind-turbine height.

I first blogged on it and how it can affect the wind turbine farce using data from Garrard-Hassan. But that data from 2011 which shows the slowing of wind speed across Northern Europe seems to have been (how should we say…) overlooked.

The full 2011 post is Here: Wind Speed Decline: A Blip or a Trend?

Here's the Garrard Hassan graph (this only goes to 2005)

But whatever the effects on marginal power producers, clearly wind speed is something that is getting more benign. Maybe it is due to Global Warming, maybe not. But whatever, wind speed is not getting worse.

Global Warming may well have deleterious affects. But (like this) there may also be positive outcomes

It’s just nobody wants to tell you about them.

Is there Something (Else) Wrong with Wind Power?

We all know wind power is intermittent. I thought I would take a look at how predictable windpower intermittency is and how accurate wind power output predictions are.

In the process I think I have tripped over a new issue regarding wind generation (but more on that later).

The bmreports site (HERE) has a section on wind generation and shows a graph of an original output prediction, a more recent and accurate revised prediction and also the actual out-turn.

The original forecast value is done 41 hours before the start of the forecasted day. The revised forecast is done 4 hours before the start of the forecasted day. The predictions use weather forecast data for the known wind farm locations and factor in a range of other parameters. These are sophisticated predictions and are probably as good as they get.

Here is a few example snap shots taken in the last month from the bmreports site.

But as well as this continuously updated graph, bmreports also publish the same 3 day data as an xml file. I've collected the xml files for one month. (Annoyingly I missed two days so these have been left out. But even so I think this is quite a good data set.)

Above is a graph of this data showing the final revised prediction done 4 hours before the start of the predicted day (red) and the final out-turn (blue).

(I've left out the original prediction as for obvious reasons, it was more in error of the final out-turn and so added little to the graph). Note: Actual metered capacity is actually 8972MW so the graph is unduly kind stopping at 8000.)

The first thing that can be seen is that the out-turn is often (not occasionally) in significant variance with the predictions. The graphs may be the same shape but the values at any one point in time are often significantly different. Clearly, any system with a large wind component that relied completely on even a near term forecast (and without spinning reserve) would soon end up in deep trouble.

So whatever the pro-wind zealots preach on Twitter, the problem with lack of wind power predictability has not gone away. Neither has its intermittency.

But potentially the example bmreports graphs (as well as mine) also show another problem. 

Notice in the above graphs how on the occasions the wind output rises above about 30% capacity (3000MW), during the rise, the out-turn lags the predictions and the maximum out-turn is significantly less than either of the predictions. 

It is as if a large proportion of wind turbines exposed to a rising wind and high wind periods are being feathered (or throttled back) for some reason during these periods.

At lower wind speeds there are still periods of great discrepancy between prediction and output but the tracking between prediction and output does appear more coherent. (Remember this forecast was done 4 hours before start of predicted day!)

Wind energy companies only get paid when they are generating. So why would they throttle back their turbines in high winds?

And the answer to that I believe is good old repair and maintenance.

For almost any machine, if you run it lightly it lasts longer. Take a car. The harder you drive a car the more wear and tear it suffers. Just about all rotating machinery obey this simple rule – including wind turbines.

We know that there is a severe generic problem with wind turbine gearbox reliability. (See This Post - The Ghost in the Gearbox and Post - More Ghosts in the Gearbox )

I would suspect that it has been found that if the loading on a wind turbine gets above a certain value the wear rate and maintenance/repair cost will be far more than the return from the extra energy generation.

So maybe operators are unilaterally and quietly deciding that when the wind gets too changeable or too strong, the turbines will be run at reduced output compared to what they are supposed to be capable of.

Wind turbines are capital intensive. If you suffer a catastrophic failure you will ruin the huge and guaranteed profit (subsidy included) your turbines can make. Do it too many times and you may end up going bust. Better to ignore the whole reasoning, propaganda and hype associated with why the thing was built in the first place and go for the low hanging fruit.

Remember most windfarms have a 25 year subsidy regime locked in place. It's a nice little earner. Operators are going to do whatever it takes to maximise the financial gain over this period and if that includes reducing output to make their gearboxes and other expensive components last a bit longer then they will do it. The abatement of Carbon Dioxide can go to hell.

This, of course, makes an even bigger mockery of the often hyped “Installed Capacity” figure than it already is. It also shows how the unreliability of these machines impacts the supposed reason they were built.

It means that wind power is perhaps even more useless and under-achieving than first thought.

I cannot prove the operators are intentionally throttling back their turbines to reduce their maintenance bills. 

But I bet I'm right.

Wind Turbine Design, Cube Laws, Efficiency and Cock Ups

Well, I have to 'fess up to having made an error regarding the output characteristics of modern day Industrial Wind Turbines.

A silly mistake at that.

But possibly a mistake that also reveals some interesting possibilities with wind turbines. Especially related to reducing their size, noise and increasing useful power output.

Crack Pottery? Possibly. But I've not been at the cider yet. (honest)

First, in order for this post to make sense, let me summarise some things that ARE true.

• The energy in the wind is a cube of the speed. In other words if you double the wind speed – wind contains 8 x energy. Halve wind speed- wind contains one eighth the energy.

• The theoretical maximum amount of this raw wind energy that can be harvested is 59.3% (Betz's Law)

• In reality the most efficient turbines manage about 45% (at a wind speed of around 7-8 m/s).

All of the above are correct. (Or I really am in trouble!)

My mistake in some earlier posts was to assume the efficiency of a wind turbine was roughly constant across the operational wind speed range (up to maximum output). 

Sadly this is nowhere near true.

In reality the efficiency (or how much energy the wind turbine can actually suck out of the wind) drops like a stone as the wind speed increases.

For most industrial wind turbines the highest efficiency (at around a wind speed of 7m/s) is about 45%. But as the wind speed increases, the efficiency falls to around 10% at a 90% loading.

The overall effect of this is to roughly linearise the power output to the wind speed. So instead of getting eight times the power out when you double the wind speed you only get double the power out. The rest is spilled.

So what does this matter if the thing is only as efficient as a 19^th century steam engine when confronted with a high wind?

It matters a lot.

Way back in 2002 at the Lee Ranch wind turbine research facility in New Mexico, it was discovered that 50% of the annual energy output of a wind turbine was delivered in 15% of the time. 

My own analysis done back in 2011 showed that for a three month period the whole UK wind turbine fleet delivered 50% of its energy in 25% of the time. But remember that was for the whole distributed fleet. 

It would be reasonable to assume that for a single facility, the Lee Ranch figures are roughly correct for the UK too. Also, there is no reason to think any design change to wind turbines since 2002 will have significantly affected these Lee Ranch findings.

In order to harvest the 50% of the energy that is smeared out over 85% of the year you have to compromise the turbines efficiency at higher wind speeds. The result today is an enormous unreliable monster.

So, for a moment, let us forget about the grindingly low 50% of energy generation that gets smeared over 85% of the year. Let us concentrate on the other 50% that arrives in 15% of the time (currently at an efficiency of a measly 10-15%).

For arguments sake, let us design a turbine that may not cut in until the wind speed is 12 or 14 m/s but then delivers an efficiency of 40%. It will (MWhr for MWhr) be very much smaller, simpler and more robust than a conventional turbine. 

OK it will only operate for 15% of the time and it is truly intermittent. But all wind is intermittent. Remember a conventional turbines output during 85% of the year is pretty derisory anyway. Often it is so low that it might as well not be there.

So, build smaller more efficient turbines. Crucially, in order to make these turbines more efficient, they only operate at higher wind speeds. We then rely on gas backup for the rest. More predictable, less environmental impact and more reliable (due to narrower operating domain). 

Tell me where I'm wrong. (Seriously - I may well be)

Of course this is still all window dressing. This (and the rest of RE) is just Care Bear fluff. Nuclear plant (with some gas) is the ONLY viable option to cut GHG and air pollution.  

But I hope that this is at least “interesting” fluff.

Wind Speed in Decline: A Blip or a Trend?

It has been knuckle chewing time for the last couple of years for those wind farms that have been stupidly built in the less windy parts of the country. Even those built where the wind actually blows have seen their profitability massively cut. But those who had been planning to cash in on sub 20% capacity factor outputs are now beginning to feel the heat.

Of course we all know that none of them were, are, or ever will be, viable without a massive ROC subsidy. But even with this subsidy some must now be trading on the margins of viability.

Last year for example the output of all UK wind farms fell by 7%. Yet in that same year many more turbines were built. The theoretical (some say imaginary) total wind-farm capacity increased by 13 %.

To me, that looks like over a 21% drop in total.

Ouch!

An unpredictable long term reduction, getting worse year on year. Just what the bankers want to hear (not).

2009 wind speed was low, last year it was lower still.

So, is this a blip? Or is it a long term trend?

Oh, such a quandary and who has the answer?

Actually it is our friendly BWEA to the rescue. Or rather a paper presented by the doyens of the Wind Turbine fraternity: Garrad Hassan and Partners Ltd

I hasten to add this paper was presented first in 2006 and is now dated 2009, both dates are before the current downturn.

You can find the PDF of their paper Here  (if it disappears, Billothewisp has a copy)

It is titled:

LONG-TERM WIND SPEED TRENDS IN NORTHWESTERN EUROPE

The running 15 year trend with wind speed, according to Garrad-Hassan is as follows

It is going down. Now remember this was up to 2005.

Garrad-Hassan then tried valiantly to use some weather indices as proxies to go back further. Back to the 1960's in fact. The most important of these is the North Atlantic Oscillation (NAO) then there are two other indices used. One is Katalog Der Grosswetterlagen Europas. This is a subjective catalogue of large scale weather patterns over Europe dating back 100 years. Then finally they also used the UK Jenkinson Lamb weather classification (which is similar to the Grosswetterlagen catalogue but for the UK)

Here is what they found for the NAO

here is the Jenkinson Lamb result

Finally here is the Grosswetterlagen graph

Notice how they all roughly correlate.

Also notice the "blip" around 1995.

In their conclusions, Garrad-Hassan try and sweeten the pill of the 15 year decline by suggesting that all that was happening was that wind was returning to stability after a upward blip in the mid 1990's.

However we should remember that this is then essentially returning to a stable "low" wind-speed. Garrad-Hassen re-assuringly write that a further fall in average wind speed should not be assumed. Though, they could not rule it out.

But of course, this Garrad-Hassan data only goes up to 2005. Since then we know that things have actually got worse (significantly so in the last year)

So, are we just bottoming out? Or are we still going down?

Perhaps our previously loan happy banking fraternity should look a little more closely at what they might be letting themselves in for.

Maybe the wind turbine carpet-bagging fraternity will be seeing that big red stamp that spells out "DECLINED" being used a little more on their loan applications from now on.

Maybe a few of their pals who have built these things in totally inappropriate areas will soon be queuing up at the local Licensed Insolvency Practitioners office.

Then I expect the poor bloody rate-payer will have to fork out to pull the things down.

What a waste.