That's a tricky question for me, not being an engineer. I'm aware that there are options since some of these lines have been built. I think there are new conductors that could decrease the losses. Some of the change, I think, in the technology from the AC to HVDC for going longer distances can also help, but I don't think we've seen any kind of analysis of the cost benefit on that.
In fact, the place where you might want to be focusing such a thing is how much mileage you can get out of the electricity that is delivered already, the efficiency at the end points of use as opposed to the efficiency of the delivery over the wider grid. I think a lot more of the losses occur as you step down into distribution and the end point as opposed to bulk transmission.