Some US government site:
Energy Information Administration (EIA) - Annual Energy Review
Energy use for transportation versus electrical energy use is about 3 against 4. Average fuel consumption is about 14l/100 km, that gets you about 140 kwh worth of energy on average(35 MJ per liter for gasoline). Electrical cars get from low aptera type 6kwh/100km to 21kwh for those like tesla and heavier cars. Taking 20kwh average that means about 7 times less energy consumption. 61% of the energy consumption is in gasoline which powers mostly cars, and those could be replaced.
So from those 3 parts of energy, 60% to be replaced nets 2, which given that EVs use by my estimation 7 times less gives 0.29 parts. Compared to previous electric energy use, this figure represents about 8%.
Its a crude approximation. As all of mine always are
/edit:
I dont know if that is average fuel consumption of cars or average consumption per miles driven (some cars drive more), but since many cars are actually SUVs... I cant imagine it.
