That's going to be the interesting point. To expand on my previous point, electric vehicles (right now) are a small fraction of the general automotive population. The power delivery grid is capable of handing the large amounts of current required to charge one of these devices. The world is currently taking large bulk power generation facilities offline in favor of much smaller renewable sources. As those large sources go offline and more electric cars come online, we either put wind turbines and solar panels literally everywhere (remembering that the sun doesn't shine and the wind doesn't blow all the time) or you get a specific amount of charge for your car, and when it's gone it's gone. How it's going to play out is a story that's not told yet, but I think of it like a playground see-saw. More cars and less energy generation means one side is unbalanced.