Tuesday 4 January 2011

Wind Turbines: Useless Down Under, Too

As promised, I'm limbering up for a dissection Crapper Huhne's electricity market 'reforms' ...

In last year's cold January snap we noted the uselessness of wind power on many a cold, still day when we urgently need it for heating. Same again this winter, of course, with several recent periods when wind generation output has been less than 5% of its rated capacity for whole days at a time according to the data from this useful website. That, of course, is because still air often coincides with extreme cold.

Interesting, therefore, to note that in Oz they suffer from the other side of this exact sam
e coin: bugger-all wind output on hot days, when they urgently need it for air conditioning !

The Australian Energy Market Operator yesterday revealed ... "During the top ten per cent of summer peak demand periods, approximately 3% of total wind generation-installed capacity contributed to demand." Energy Users Association of Australia said ... "Wind does not work on hot days and there's been incidents. That obviously means we're going to have to build more generation."

Wind-farm mania is clearly sans frontier.

ND

10 comments:

Budgie said...

We'll pretend that windmills work, if you pretend the globe is warming.

No one would build windmills unless they were subsidised. No one would subsidise windmills (or pv cells etc) unless they accepted the man-made-CO2-causes-global-warming hoax.

That hoax may be crumbling but the politicians are still in thrall to it. The politicians are also still in thrall to the notion that they can pick winners.

Who said vote for Cameron?

Bill Quango MP said...

Who said vote for Cameron?

"We fight as we must, not as we ought."

Budgie the choices were all on the table.

If not Dave/ George, then today you would have;

Gordon/Ed
Nick/Vince

or possibly

Gordon/Vince

Not very appealing options.

Budgie said...

Or UKIP?

or BNP?

or ED?

And what would have happened if we had a Labour/LibDim coalition? Gordon would have gone because that was the price that Clegg demanded. The chancellor would have been Alistair D, and the fiscal picture would have been pretty similar to today.

Better, Call-Me-Dave would have been out on his ear and a real Tory party emerged.

What have we got now? More EU, which our quisling PM is afraid to even acknowledge. More global warming tripe. Fake "efficiency", but continued spending where we cannot afford it.

Anonymous said...

Unlikely to have been Darling and Dave Milliband.

Ed m. and Alan/Vince.

Another unappealing choice.

rwendland said...

bugger-all wind output on hot days, when they urgently need it for air conditioning!

Maybe a problem for the aussies but for us poms windpower is better than average correlated with high electricity demand, both higher day to night and winter to summer.

As this paper says:

"The increase in daytime wind capacity factor is most
pronounced in summer, with overnight capacity factor
figure of around 13%, and a peak daytime capacity factor
of 31% (average summer capacity factor of 20%). In
comparison, winter output varies from 36% overnight to a
peak of 44% during the day, with a winter average capacity
factor of 38%."


So in terms of income generation the usually quoted 30% UK capacity factor for windpower significantly understates the financial position of windpower. Probably more in the 40% to 45% range capacity factor for pounds sterling compared to the 30% for MW. Be interesting to find a paper that analyses this more fully.

Budgie said...

rwendland - that is really scraping the barrel for wind, isn't it?

The point is that windmills are unreliable, because the wind is unreliable, whatever their apparent capacity factor. Wind has to be backed up by conventional power, constantly on standby, for grid stability, (unless wind is used to directly drive pumped storage) all of which effectively doubles its cost.

So "No one would build windmills unless they were subsidised. No one would subsidise windmills (or pv cells etc) unless they accepted the man-made-CO2-causes-global-warming hoax."

Nick Drew said...

Mr W: your points are taken, as far as they go, but - whilst not going quite as far as Budgie's last para, it must be said that the problem is not represented by average capacity factors - it's the high variance, and unpredictability with it.

From time to time I keep an eye on the Elexon website, and when they say that wind output is hard to forecast, they mean it !

In recent days, out-turn capacity-factor has varied from less than 5% to over 50% (never much higher), so that the "27% average" (as well as being pretty wretched in any event) is sitting between swings between almost zero to just over 50% - with very little warning. Nudging this up by the odd percent doesn't do much to offset this problem.

Anything that can fall to near-zero without much warning must be backed up (as Budgie says), as soon as the absolute scale of the wind fleet starts to exceed the inbuilt tolerance of the system as a whole (and check from Elexon just how very accurate the demand forecasts are, by stark contrast - they just ain't geared up for large, wild supply-side swings)

Incidentally, although the paper you cited (for which thanks) claims to have built in maintenance downtime etc, I am very confident (having offshore experience from my days in the oil & gas business) that offshore downtime will be significantly greater than currently acknowledged

rwendland said...

Budgie: You're right that wind will require a substantial reserve capacity, but important to remember it requires near-zero expensive "spinning reserve" or equiv - what it needs is substantial reserve that can be called for between about one and twelve-ish hours ahead. Wind is actually extremely reliable on a one hour time horizon, as it is so well dispersed in small units that on that time horizon you do not have to worry about failure, unlike other plant.

The tall straw for the National Grid's spinning type reserve is actually the Sizewell B nuclear power station at 1,200 MW, which largely defines the spinning type reserve requirement to cover it faulting out. You may remember much of the south-east suffered a power cut a couple of years back when this did not work as planned when Sizewell B tripped out. When/if EDF build a new 1,800 MW EPR nuclear station in the UK, National Grid will have to contract more reserve to cover this - in the near term this is a larger change to our reserve requirements than wind I suspect.

(NB There are larger generators than Sizewell B, like Drax, but they are organised in multiple units of around 600MB, so the largest credible single point fail is around 600MB. The second straw behind Sizewell B is the HVDC interconnect to France which has 1000MW single poles, which I think have a remarkably high fault rate equiv to about 6 whole days per year (for both poles) of unexpected outage.)

I'm not saying wind is some magic wand, and I am not sure it should go beyond 15% of UK nameplate capacity (i.e. about 5% of annual generation), but I do think the problems of wind are often overstated. I think there is the prospect of it becoming perfectly economic as the economics of scale impact the production of multiple small units, and carbon fuel prices increase in the medium term.

We are after all still subsidising past nuclear to the tune of £2+ billion a year for the NDA's £73 billion clean-up programme. I'm not averse to startup subsidy on some new generation technologies, while acknowledging the risks in the "picking winners" problem.

rwendland said...

ND: I'm certainly not a denier on the variance and unpredictability issue. However my take on this is that this problem is frequently overstated.

It's not much use looking at that Elexon webpage, as the forecasts they show there are approx two days ahead ("Initial Forecast Value") and seemingly roughly one day ahead ("Latest Forecast Value") according to 5.2.2.2 of the system spec.

Operationally National Grid, as I recall, do four hour ahead wind forecasting which they say is about 10% accurate, and will probably improve to about 6% accurate as more modern wind generators are deployed and forecasting improves (not sure if that is +-10% or a band of 10% = +-5%). I remember reading somewhere a claim that if one hour ahead forecasting is implemented, ideal for our half-hour settlement period regime, then wind power forecasting would be very accurate - though I'm a bit dubious about this claim given what I've read about the wind shear problem.

All this is discussed in depth in National Grid's Operating in 2020 consultation a year ago, and a BERR commissioned report prior to that consultation.

rwendland said...

ND: I'm certainly not a denier on the variance and unpredictability issue. However my take on this is that this problem is frequently overstated.

It's not much use looking at that Elexon webpage, as the forecasts they show there are approx two days ahead ("Initial Forecast Value") and seemingly roughly one day ahead ("Latest Forecast Value") according to 5.2.2.2 of the Elexon webpage system spec.

Operationally National Grid, as I recall, do four hour ahead wind forecasting which they say is about 10% accurate, and will probably improve to about 6% accurate as more modern wind generators are deployed and forecasting improves (not sure if that is +-10% or a band of 10% = +-5%). I remember reading somewhere a claim that if one hour ahead forecasting is implemented, ideal for our half-hour settlement period regime, then wind power forecasting would be very accurate - though I'm a bit dubious about this claim given what I've read about the wind shear problem.

All this is discussed in depth in National Grid's Operating in 2020 consultation a year ago, and a BERR commissioned report prior to that consultation.

NB Had to remove some handy URL links, as the Blogger software was rejecting them for some reason! Sorry.