[captainmuon]

> Because solar is intermittent, and isn't practical at all in many parts of the world.

The solution to that is simple, use less power at night. I.e. don't make so much aluminum when there is no sun or wind. We could decide as a society to trade a few percent of our wealth for using much less coal and nuclear if we wanted (and if our society were organized in a rational fashion).

Also: don't heat with electricty, but use e.g. solar thermal or geothermal power.

[Recurecur]

Night isn't the only source of solar intermittency, overcast also has a large effect. Solar also isn't cost effective at higher latitudes. When people are freezing to death, your simplistic approaches won't appeal much.

Efficiency is great and should be encouraged. We still need increasing amounts of reliable, plentiful and cheap energy going forward. You may be willing to accept a diminishing standard of living, most are not.