I don't think many production lines are going to be start stop. If your production line is only running 70% of the time, and all of your running costs actually

I don't think many production lines are going to be start stop. If your production line is only running 70% of the time, and all of your running costs actually scale with that (which they almost certainly wouldn't), then you are still looking at 30% less return on capital investment. And most high energy consumption industry has massive capital requirements. Instead I think the adaptation will be in energy storage (both at consumer and producer) and simple energy overprovisioning. I have hopes for storage. Especially low efficiency but incredibly cheap and scalable storage. If we can store 30% of wind surplus in summer and use it in winter, that would be amazing. It would also help ensure energy security.