Ann: Impairment of Cooper Basin Assets , page-14

Okay, I found what I was looking for;

It was labled a confidential Final Report to Australian Geothermal Association - from 2009 ( not so long ago after all, but a world away in comparitive circumstances ).

The document title is;

"Preliminary Assessment of the Value of a new 275 kV
Transmission line to connect Geothermal Resources to the
NEM in South Australia"

Hard for me to post the link because it appears to be from the Petratherm site but only has half the web address, however if you google the document title you should find it.

A little dated ( still talks about Olympic Dam as a major factor ), but does set out some cost & benefit analysis for transmission lines connecting to the grid, but also an estimate for indirect economic boost along the transmission route.

In fact, this is the only real number crunching I have personally seen regarding costs of long distance transmission links to the grid - might be something the Geothermal association could dust off & get updated as part of a "direct-action to tackle Tony now" agenda - especially if the lines could pay for a good part of their cost in the medium term via additional economic activity resulting from the lower cost base power they avail on route.

The icing on the cake would be a pickup in confidence in the mining sector that finally tips Olympic Dam over the line to go ahead (yeah yeah, okay; but I can still dream!).