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)?

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.

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.

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.

"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.

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!