Really it's the other way round: all the generators have safety trips and can disappear from the grid in a short time if required, but it's uneconomic to do so.

Really it's the other way round: all the generators have safety trips and can disappear from the grid in a short time if required, but it's uneconomic to do so. Which is why you get things like wind farm curtailment payouts; they're part of the weird set of compromises between spot market and long-term (necessarily central!) capacity planning.