Sylvia,

Read the Victorian document more closely, please.

"15% of the total capacity of wind generation was assumed to be firmly available at all times and could be relied upon to provide capacity during peak periods."

This assumption is reasonable; they have done their homework. Elsewhere, sufficiently-diversified wind earns up to 20% "capacity value"; this falls to 9% or so with very high penetration (wind capacity exceeding minimum demand).

http://www.sd-commission.org.uk/publications/downloads/Wind_Energy-NovRev2005.pdf
http://ejournal.windeng.net/3/01/GGiebel-CapCredLit_WindEngEJournal_2005_right_links.pdf

So 4.5GW of 20%-capacity-value wind generation can replace (without gas-fired firming) 1GW of 90%-available coal-fired baseload. *And* it can produce 4GW on a good day, predictable well in advance so there's time to switch off more coal.

Cost *is* what is going to decide these things. Retiring coal-fired power stations early isn't free. Yes, wind integration costs money and intermittent generators ought to pay for any additional peaking capacity required.

But the assumption that firming gas generators would have to be equal in capacity to wind and run at 70% capacity factor to make up for wind at 30% is a gross exaggeration. It would be accurate if there were but one wind farm and one peaking generator in a network with constant demand. It is *not* the case with many windfarms supplying variable demand across several states.

Adding solar, wave and tidal energy to the generation mix would further diversify and smooth the daily aggregate profile of intermittent power.

Future estimates of cost are guesses at best. There is little doubt that immature and underutilised resources -- biogas, solar thermal, wave, tides -- are expensive today but can be expected to see dramatic cost reductions.

Quotations for more mature wind and nuclear power are probably more accurate, but still vary widely because of the different discount rates applied to the cost of capital (which is comparable for the two). Wind is a much less risky investment in terms of delays and cost overruns, so I'm inclined to believe a low discount rate is applicable to wind and a high one to nuclear.

Wind generation alone costs about $60 per megawatt-hour, or $70/MWh "firmed" with gas backup.

Compare

http://www.rmi.org/images/PDFs/Energy/E05-15_MightyMice.pdf

“I don't think that will happen, without a really big shock to the system somewhere.”

Maybe Yabby, although we are seeing a quite amazing amount of concern about climate change being expressed across all sections of society. This seems to have been galvanised by one person; Al Gore.

So I think it IS possible for us to get the necessary psychological change without having to suffer a crash event first. We just need the right sort of leadership to get the process rolling.

Given the amount of concern about climate change, peak oil and so on, it should be a relatively easy step to morph it into widespread concern about overall sustainability.

Unfortunately we are not seeing the necessary leadership emerging, and neither are we hearing the right stuff from the Greens or Democrats.

So this is all the more reason why organisations such as the Clean Energy Council and many others that would comprise a component of a holistic sustainability approach must NOT just stick blithely to their charter but MUST push hard for the implementation of that overall philosophy.

"Maybe Yabby, although we are seeing a quite amazing amount of concern about climate change being expressed across all sections of society."

Thats true, but everyone wants everyone else to change. I'm told
Al Gore's power bill for his house is huge. He still flies in
a private jet. etc. etc.

Whatever we do, its a global issue and that includes population.
Until we address those core fundamentals, its a great big
feelgood exercise and little more.

The market will regulate alot of it. As energy becomes expensive,
people will be forced to change their habits. That will work
better then any regulations.

Fact is if you have another 5-6 billion all wanting to live
a cushy lifestyle, with ever more airconditioners and cars,
the wheels will eventually fall off and the system will crash.

Nature has a way of sorting these things out in the end.