Thanks for your response.

1) It's something to consider, if only in an appendix. "We could make the transition easier if..."

2) I didn't see the efficiency gain bit, browser formatting issue, the table was a bit wide. I'd quibble with some of the numbers but that's a bit pointless, and anyway only time will tell.

3&4&6) "We wanted to convey the understanding that there would be no direct individual wealth benefit from this expenditure."

As I noted, this only seems to happen with renewables, hospitals and so on. When someone whacks down a road or builds a frigate, we speak of investment, and jobs gained. That is, a direct indiviual wealth benefit. When renewables and the like are built, we speak of "cost" and "loss of wealth."

So building things gives us wealth, unless they're things we disapprove of. No.

4) "Current expenditure on replacement/refurbishment of existing fossil fuel fired stations only amounts to about $2b per year."

You missed "fuelling" them. Any generation system you choose has three basic expenses: building, fuelling and maintaining the things. Let's assume the maintenance for all is about the same. Fuel's not required for renewables, except for biofuels. So that removes a large cost.

How much does it cost Hazelwood to get its coal? How much does it cost Altona to get its gas? Okay, take those annual figures and multiply by 41 for the years till 2050. That adds some billions to the cost. Billions we wouldn't have to spend if we were replacing them with renewables, whose fuel (except for biofuels) is free.

But aren't we talking about fossil fuel depletion here? Won't fossil fuels get more expensive over the next forty years? That puts the cost of BAU up further compared to renewables.

I'd be interested in your sources for the costs of the renewables, too. They're higher than other figures I've seen.

"While Australia is pursuing a renewable future the rest of the world is doing the same."

That's not clear at all. If the rest of the world were doing so, then it's likely the costs of renewables would be much lower than you suggest. Most likely, though, some of the world will do it while some doesn't. If nothing else, the Third World is unlikely to be pumping out gigawatts' worth of solar photovoltaic cells. But they'll still want electricity. If they have demand and we have supply, well there you go, billions in exports.

"With the current state of the renewable industry the pursuit of a large renewable energy increase will be result in much higher inports than it will exports."

That's the "current state" certainly. But it's inconceivable that we could be spending $90 billion annually and not develop some local industry. I suppose we could bollocks it up if we really tried, perhaps hire some ex-GM or AIG executives. But probably we'll do better than that.

"No bias against geothermal. As you say the technology is not sufficiently developed so that we are able to get a reasonable stab at the implimentation costs and utilisation."

This must be my day for people misreading me. I didn't say the technology was undeveloped. It's very well-developed indeed. I said Australia was not well-explored for geothermal resources. You ought to have at least noted this in passing. If you expect to present this to a Senate committee or something, well Senators are not brilliant, but some of them might notice the omission; it's best to deal with questions before they even come up.