But the electric car can be the tool to enable wider use of intermittent-supply renewable energy, like wind or solar! With some smarts, the cars can be charged at high supply/low demand times, and even feed energy back to the grid when demand is high and supply is low.

There is money to be made in making this happen, people!

Also, I did the math once on how much extra power a city will need if all cars go electric. It is not that much: take Perth, Australia, as an example. We have about 5.5 GW installed power generation capacity (there is a huge gap between this and the actual usage which peaks at less than 3.5 GW usually, but that is another story...). We have say 500,000 cars, driving 40 km/d on average... that's 20 million km driven, at 5 kwhr/km we need an extra 4 million kwhr/day. If the charging is spread over 20 hours, that is an extra 200 MW required to supply them all. A 200 MW power station is small-ish.