The are plenty of electrical plants that burn oil.
Relatively few. On a cost basis, oil's been more expensive than coal or gas. The former is still widely used (and serves as the bulk of electrical generation in much of the world). Solar and wind are approaching parity with coal, but are not dispatchable. They're available when they're available, and you can shed excess, but there's no accelerator pedal: you can't turn on the sun (or the wind) when you need them.
Solar thermal gives the option of banking energy for a few hours (about 6 presently, proposals for several days' capacity exist). This would address load balancing to a significant extent, but solar thermal plants must be specifically constructed, they're not suitable for opportunistic deployment as solar PV is.
Because even if you rationed oil for transportation, it's still going to grow sparse - and there's no reason to believe that the demand for transportation is going to go down. At best, the rationing scheme will slow down the current problem, and then you're back to where they are right now, trying to find viable and cheaper replacements for oil.
Relatively few. On a cost basis, oil's been more expensive than coal or gas. The former is still widely used (and serves as the bulk of electrical generation in much of the world). Solar and wind are approaching parity with coal, but are not dispatchable. They're available when they're available, and you can shed excess, but there's no accelerator pedal: you can't turn on the sun (or the wind) when you need them.
Solar thermal gives the option of banking energy for a few hours (about 6 presently, proposals for several days' capacity exist). This would address load balancing to a significant extent, but solar thermal plants must be specifically constructed, they're not suitable for opportunistic deployment as solar PV is.