[mschuster91]

The cables don't need to be massive, but the voltage has to be because the power loss is related to the current flowing - so the Chinese just raised the voltage to 1 million volts instead of the usual 220/380 kV, and used DC instead of AC to get rid of reactive power and skin effect issues. Their longest line transfers 12 gigawatts of power over almost 3.300km distance - that's not that much that remains to cover the distance from the US East to West coast!

[1] https://en.wikipedia.org/wiki/Ultra-high-voltage_electricity...

[sophacles]

The large long distance AC transmission lines are 765KV. They step that down various substations as lines branch off to feed smaller and smaller areas until you get to the distribution network.

If you draw the map of lines with proportional thickness for various voltage levels it looks vaguely fractal, like an old tree.