Well, the losses over 50 km should be pretty small at the voltage level involved.
I've heard of plans in other countries to raise conductor temperature for certain "bottlenecks" in the grid. There appears to be new high temperature conductors on the market, but I take it from your post that they intend to use the existing conductors?
Off topic: The electricy generation situation in Sweden just took the strangest of turns. A dozen industrial buyers created their own power company to get a better price. They agreed with the Russians to build a 1 GW subsea cable to the Leningrad reactors.
