Aluminum smelters are something like 4% of global electricity consumption and 60% of them are in China. In general industrial is less than a third of electricity consumption in the US, not even all of that can be curtailed, and that number is only going to go down if we electrify heating and transportation. It's pretty hard to curtail heating and cooling by more than a minor amount. It's easy to do with transportation over the course of hours or days, but not weeks or months.

Batteries work great to let you generate power at noon and use it at dusk. They're not so great at letting you generate power on days with a surplus and then use it later in the year when there is a multi-week or seasonal shortfall.