Some years ago, I calculated that a total replacement of petroleum transport fuel would require a 40% increase in US electric generation at worst.  Given that the typical efficiency of light-duty vehicles is considerably less than 20% and electrification of freight via railroads and e.g. Bladerunner trucks would have substantial cuts in energy demand, we might be talking 30% or even less.

Add to that the potential reduction in transportation from relocalization, and the percentage would drop even further.