Because every industry has capital costs that you want to repay by using it as much as you can.
There is a very small amount of people working on low-capital industries (normally with higher operational costs), and they seem to be close to some gain here or there. But almost all of our knowledge is biased against turning things off.
> Because every industry has capital costs that you want to repay by using it as much as you can.
that's the bit I don't quite understand - yes, in a simple economic model where you want the numbers to go brrr, it makes sense, but is there a physical limit? could a country decide to own the big facility and use the excess electricity and sell the results to commercial ventures? the government can afford to have a piece of land taken that doesn't return a profit 100% of the time?
I am uniformed on this, but those industries likely take time to scale up. A large scale desalination plant requires a significant amount of infrastructure.
No one will want anything from your desalination plant in Norway, and shipping water is not a thing because it becomes too expensive.
The next problem is energy cost vs. duty cycle. The less you run due to only utilizing cheap prices the higher the impact of fixed costs on your business.
Smelting cant base their production on when excess energy might be available. They need that energy now. Desalination might be a good sink but again, if water is needed now and there's no excess then what? That's why we have base load.
