Nuclear Fusion

[Excession]

I would normally assume that transmitting power from New York to Los Angles would be either spectacularly rare, or that power production would simply follow the sun and happen at set times. Either way, it seems more efficient than any storage I've ever heard or (unless you are already assuming a superconducting cable: the cost of keeping that cool might blow your mind).

We already have times when "every person can't draw arbitrary amounts of power from the grid". We call it "summer". I remember my parents putting in a device that turned off the AC at points during peak use in return for a lower rate during the 1980s. Long before the "smart gird". Not sure how it worked, probably cut in when voltage was less than 115VAC (from a 120VAC nominal).

Just looked up information about long distance power transmission. The longest, or at least one of the longest now, goes across a big chunk of China, bringing hydro power 2000km to Shanghai. That's an ultra-high voltage DC link, running at 800kV. Transmission losses are less than 7%, which seems pretty good. OTOH cost is listed as US$440 million, which is not cheap at all. That's still only a tenth of the half way around the world link you'd need to supply solar power to where it is the middle of the night, but it is impressive.