Seriously SMES technology, an entire grid of superconductive power lines, we'd pretty much be able to switch from oil to electricity overnight and increase the range cars can drive during the switch (more if we created maglev cars). The need for baseline power would be a thing of the past because we could loop the power grid and turn the entire thing into a massive battery (a virtually lossless battery). It would also allow us to account for the ebb and flow of fairly random renewable sources of power but working as a virtual UPS and power stabilization unit.
We could build massive arrays of nuclear power plants off in the boonies where nobody would go NIMBY on their ass and conduct the power to everywhere else in the US. It wouldn't instantly destroy our need for fossil fuels but it would completely and utterly remove our need for oil.
"You drive that old oil sucker? But can only drive like 500 miles on a refill. My car has a 10 MWh SMES coil. I've never recharged it. Got it from the dealer precharged with a special deal they were running, "The first 30k miles are on us!"* Hell I could run my house on this thing."
We'd still need to green up the power grid, but this one invention would completely demolish oil as we know it.
* .27 kW/h for average electric car, 10 MW/h coil = 37,037 miles per coil charge. Current electric cars like the Tesla Roadster have about 50kW/h max charge.
** Might be better to run a much lower current properly insulted. It occurs to me that this kind of force would turn the car into a massive superconductive magnet to the extent of being able to fly (with a proper track).