It is another 20 percent power consumption, mostly coming from residential areas at night. - the average nighttime draw from any given residence will go up by 20kwh/8h/220v: 11/22 amps. (one or two cars) The maximum draw (full recharge in 8 hours) from the same residence goes up by 110 amps. This assumes people dont buy speedcharging gear for their homes, which I think is a safe assumption. I certainly do not wish to have electrical equipment able to recharge a 100kwh battery in 30 minutes in my garage. I think the existing grid infrastructure will suffice for this with only minor upgrades, but a lot of residencies are going to need their fuseboxes and bits of their wireing beefed up. Lot of work for electricians.

Another data point:

It takes a lot of coal to make gasoline

Quick draw critics of the electric car often (miss their target) criticize EV's because in their words "Electric cars simply replace a tail pipe with a smokestack" The gist of their argument is that the emissions still occur, not at the tail pipe but at the electric power plant. That great observation is usually followed by the statement that 45% of our grid electricity is coal and coal is dirty thus the EV provides no net gain.

(...)

It is a simple fact that just the refining of gasoline requires approximately 6 kwh of electricity per gallon of gasoline. In fact electricity and natural gas cost are estimated to be 43% of the US oil refineries total expenses. If you tack on the energy required to extract and transport the oil to the refinery and then to the gas stations as well as the energy cost of the gas station, I'm sure that number jumps a few more kwh per gallon.

So let's be conservative and cut the oil guys a break and say it takes 8kwh to extract, ship, refine and transport each gallon of gas.

What's good for the goose is good for the gander.  Drum roll.......

It takes more electricity to drive the average gasoline car 100 miles, than it does to drive an electric car 100 miles. A gas car at the US fleet average of 21mpg will consume approximately five gallons of gasoline which took 40kwh (5 times 8)of electricity to make, to drive 100 miles. An electric car will use approximately 30 kwh of electricity (3.3 miles per kwh) to drive the same 100 miles.

This is California and power uses may be different elsewhere, but this is still an impressive comparison...

Wind power