Switching from nat gas to ... oil? Yup! I see this happening more and more. Yes there are reports of coal plants being kept around but oil is cleaner than coal and I see this being more acceptable.
But the wild card is how many power plants can be dual powered by oil or natural gas. In my home town they built their own power system back in the 50's that can be powered by either gas or oil. It is still there and kept ready for service but is still far cheaper for them to buy electricity from the grid than generate it locally. But the big question is how many plants are there like this and what is the price points for them to be economically viable to turn on.