The problem is taking the most expensive power source with a large portion of the costs being the initial investment and then not running it 100% is economical suicide.
Not if the market provides incentives to curtail, which it does with negative pricing. If other energy sources can curtail enough at the same price, they’ll do it. Otherwise nuclear will. The costs you’re alluding to can’t be avoided, but they’ll be spread across the system.
This is all predicated on the market operator actually having the systems in place to signal the need for curtailment effectively, of course. That’s a whole different question.
