I mean that the power that is still online doesn’t suddenly cost 500x more to produce. The plants are paid extra for.. not being prepared? This is why regulations exist.
Otherwise you can have a command-and-control economy, like the Soviet Union had (I'm not being sarcastic). Then a person/group in charge would decide who gets the remaining supply, rather than the price-driven market.
Energy has always been a very delicate piece of engineering, sensitive to short term disruptions. Whether or not that energy is distributed via capitalist markets or not, whether it's electrical energy, gas or oil or whatever else.