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The Forum > Article Comments > Wind power can substitute for base-load coal > Comments

Wind power can substitute for base-load coal : Comments

By Mark Diesendorf, published 6/2/2008

Wind power, with a small amount of peak-load back-up, could substitute for several of Australia’s coal-fired power stations.

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Diesendorf suggests "banning electric resistance hot water systems"

This seems odd, why shouldn't they continue to be used, but configured to switch on whenever the wind (or other variable sources) are producing excess power, rather than being configured to switch on at midnight (when coal-fired power stations are producing excess power)?
Posted by jeremy, Wednesday, 6 February 2008 8:37:32 AM
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A well written piece Mark. It's a pleasure to see someone pushing back against the narrow ideology of the IPA. Pure science doesn't get a guersey when one is still chained to the Old Testament of economic "rationalism".

Whenever the god of centralised power and wealth monopolisation is threatened, the hurdy-gurdy drones into life and the same old Morriss Dancers plat the same old corporate maypole. It's all a bit quaint.

I am not a cornucopian. I don't believe there is a techno-fix for every human desire, but here we are simply trying to marry bog-standard, established science with engineering excellence. It's not so hard.
Posted by Chris Shaw, Carisbrook 3464, Wednesday, 6 February 2008 8:58:57 AM
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Unless someone can demonstrate a real world high penetration windpower system (note this cuts out Denmark) I'd have to say the assumptions of this article are unproven. Apart from the fact that hot granite geothermal is working yet (and may not scale up) the major oversight is the huge capital cost of idle capacity. Fuelburn generators have to be on standby to meet demand at times of low windpower. When they are idle and not using fuel they still 'burn' interest and depreciation. Similarly with the notion that windy areas can compensate for becalmed areas. This means substantially more turbines have to be built in each region since they may need to carry other areas beside their own. When they are not needed they will just stand there like expensive ornaments.

Advocates of large grids usually also suggest connection by high voltage direct current cables (HVDC). We're talking huge money ($bns) for the extra turbines and transmission capacity. Note that batteries that can cheaply store megawatt-hours aren't here yet. I'd also point out that thanks to the Basslink underwater HVDC cable Tasmania has become utterly coal dependent in two short years. The notion of windpower baseload might work if somebody can find the upfront capital and customers were willing to pay exorbitant prices, perhaps 50c to $1 per kilowatt-hour. That's not gonna happen.
Posted by Taswegian, Wednesday, 6 February 2008 9:46:23 AM
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The key factors missing from the author's article is the cost per kWH which could be downright scary and the sheer number of wind turbines required to produce the equivalent power requirements of the nation. All seems a bit pie in the sky.
Posted by alzo, Wednesday, 6 February 2008 11:19:17 AM
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"Applying Ockham’s Razor, the simplest scientific description of intermittency is to say that the availability of coal power and wind power are both random variables, that is, they are governed by probability distributions, which can be derived from empirical data."

Well, no. Failures in coal power are uncorrelated - they occur randomly with respect to each other. If you have two coal fired power stations, and there's, say, a 1 in 100 chance that one of them will unexpectedly be unavailable, then there's only a 1 in 10,000 chance (near enough) that both of them will be unavailable at the same time.

If you two wind generators next to each other that have a 1 in 100 chance (I'm just using the same number, it's not realistic) of not being available because of lack of wind, and one is out for that reason, then there's pretty much a 100% chance that the other one will be unavailable as well. That is, the chance of them both being out at the same time is also 1 in 100, or 100 times more probable than for the coal fired stations.

The further apart the generators are, the less strong the correlation, but even when they're on opposite sides of the state, there's still some correlation.
Posted by Sylvia Else, Wednesday, 6 February 2008 12:27:04 PM
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I would be fairly sure that the NSW coal fired stations with factors under 60% are those which are already fully depreciated and are retained as available capacity to cover major overhauls or outages at more efficient newer stations.
In South Australia the prevaling winds are from the S.E to S.W quarter but I think that the occasional other winds come from the diametrically opposite quarter so the author's argument is fallacious unless the turbines cannot face in two opposite directions.
With regard to NSW I believe that to supply 20% of the state generation from windpower would require the order of 10,000 wind turbines. Lovely sight!
For wave power some two hundred plus kilometres of wave machines would be necessary. That wouldn't please the surfers!
Posted by Foyle, Wednesday, 6 February 2008 12:31:02 PM
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Show us the money!

Models are only as valid as the data and assumptions used in their construction. If the author's view really withstands scrutiny, then the models should be beyond criticism. So let's see them.

Sylvia.
Posted by Sylvia Else, Wednesday, 6 February 2008 3:28:42 PM
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I would be pleased to learn Professor Diesendorf’s view on accidents and fatalities in the wind industry.

A partial list of accidents and fatalities can be found at the following site and click on “accidents statistics.”

http://www.caithnesswindfarms.co.uk/

The summary has been updated to Nov 30th 2007. It is admitted that data is incomplete; however, it does represent the “tip of the iceberg.”

Could Professor Diesendorf provide southern hemisphere data? Discuss most frequently observed accidents in Australia. To bring the wind data in line with the Switkowski report could we know please the fatality rate for wind generation expressed as GWe/year.
Posted by anti-green, Wednesday, 6 February 2008 4:02:56 PM
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Mark Diesendorf's criticism of Tom Quirk's use of a "reliability figure" is unwarranted. This is essentially the same methodology that NEMMCO applies in its annual statement of opportunities (SOO). Indeed in its 2007 SOO, NEMMCO assumes only 8% of the capacity of SA wind farms.

NEMMCO is an independent body, run by power system boffins, with no axe to grind in respect of technological outcomes. They are influential in setting market parameters (e.g. intervention from time to time and the price of VoLL (the market cap price)) and, as such, one would generally expect that, with their influence, the market will be driven to provide the capacity they believe is required.

The 92% haircut to wind farms is therefore a real cost because that capacity must be found elsewhere. If a kW of wind costs $2,700 (recent Australian prices) then it also requires a further 0.92kW of back-up from, most cheaply, a gas turbine at say $600/kW for a total cost of $3252/kW.

My point here is that it is all very well for wind backers to talk about geographical diversification and new forecasting tools but if the independent, and expert, market operator is only prepared to assign a firm capacity to wind farms of 8% then that haircut is real and represents a real cost to our society. Under these circumstances the debate about achievable penetration levels is, largely, a wasted one. Any additional MW of wind gets the 92% haircut and its backers should contemplate that off-takers should sensibly be heavily reducing the price they are prepared to pay for its electricity (excluding the renewable credit).

The wind debate is rife with mis-information and confusion, but intermittency is truly a big issue the wind industry and our politicians need to face squarely.
Posted by Stuart D, Thursday, 7 February 2008 9:40:58 AM
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1/. Wind Energy pure lacks an energy storage system, which is available to all power stations, coal, oil, or nuclear. gas less so. In the "coal pile" beside/inside the station.

2/. Present wind energy technologies are "out of date" their mechanical principles go back at least to 1185 in UK, and possible to 635 AD and before in Iraq ! A fan, a gearbox, and something driven.

Modern wind energy technology pioneered by Honneff in 1932, The Third Reich 1935-45 and Trimble's Windmills 1972-82 used two rotor contra rotation to eliminate gearboxes, and improve overall aerodynamic efficiency. Some Timblemills are still operational
Work is now starting in UK to develop larger machines with better electrical technology.
See the files on axialflux@yahoogroups.com for articles/references.

3/. The best application for wind energy is heating/cooling, as when the wind blows energy loss/gain to a building increases. This can be "balanced" by a wind turbine supplying energy to the building.
Posted by ferrand, Thursday, 7 February 2008 7:53:55 PM
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No mention here has been made about response time.
Whether geographical spread helps or not there is one factor that
has not been discussed.

When wind farm output falls, to the cube root of wind speed mind you,
can the the thermal power stations be cranked up at the same rate ?

The change in level can be very large, a drop to one third in wind speed
means a drop to 1/27th in output.

Then as the base load station starts picking up the load, the wind picks up.

These are just the factors that start an oscillation which can cause
loss of system control.
I believe this is what happened in Germany.

One suggested answer is gas fired turbines, but even those have to
be kept running, just in case.
Posted by Bazz, Monday, 11 February 2008 11:04:44 AM
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