lets look at renewable energy then, page-44

I am no sparky, but can understand logic.

For a non-sparky, you're not doing too bad.

High tension power lines are made of aluminium (with a steel core) and that is not the best conductor.

The resistive loss in watts equals the current squared (in amps) by resistance (in ohms). All conductors have resistance measured in ohms/metre. The "ohms" figure is very small but the "metres" is large. Now they don't build expensive transmission lines to carry a few amps and remember that the current is squared so when the current gets in the many hundred s of amps you can see the problem. In fact they pump so many amps down the line that the conductors get hot. Another problem: If a conductor gets too hot the losses become greater (resistance is affected by temp) and the heating greater. If allowed to go too far the conductor can be ruined.

So you double the voltage on the line to halve the current. The inland HV line from Gladstone to Collinsville is 275kv. Most of what you see is 135kv. You don't go to the extra costs involved with this if transmission losses are insignificant.

This is not my field, BTW and I have not worked for a generating authority for decades so the better informed are welcome to correct me.