agl unveils australia's biggest solar energy p, page-16

Very interesting about the HVDC transmission systems. 800 kV!

They are talking about distances of 700 km.

From the Allstom website:

"HVDC can transmit three times as much power per tower compared with conventional AC. This means a substantial reduction in land costs and often no new right-of-way (ROW) access permits, particularly difficult in densely populated regions."

I would say this comes from the high voltages and thus much lower currents compared with AC, and theoretically zero loss from L/C characteristics of the line.

One other advantage I guess is that there is very little radiation compared with AC.

There are other diverse advantages, too.
http://en.wikipedia.org/wiki/High-voltage_direct_current