Maybe. You have a massive capital outlay, so it becomes a tradeoff between saving money on electricity by running only when it's below a certain price and running all the time.
Usually electricity cost doesn't dominate the equation, so it makes sense to run 24/7 (or as close to that as you can get).
Aluminium refining is different, but usually those plants buy dedicated electric capacity from a hydro station at special wholesale rates. It does not lend itself to starting and stopping.
AFAIK, aluminium smelters would have significant issues if their pots overly cooled. OTOH, their massive energy consumption can be significantly modulated which is often used for grid load stabilization.
Usually electricity cost doesn't dominate the equation, so it makes sense to run 24/7 (or as close to that as you can get).
Aluminium refining is different, but usually those plants buy dedicated electric capacity from a hydro station at special wholesale rates. It does not lend itself to starting and stopping.