Also, as others point out: the transition to EVs "fills in the bathtub" more than it adds "new" demand. In the course of a day, there is a huge demand for electricity during the day and especially the work day and it drops off somewhat sharply as people go to bed. This evening drop-off is sometimes referred to as the "bathtub" in energy demand curves because that's what it looks like in the graphs. (This is often reflected in the "off-peak" pricing and hours from various utilities.)

The majority of EVs charge overnight already. A very rough napkin estimate I saw once showed that assuming the majority of charging continues to happen overnight in the bathtub, you could replace more than half of all cars on the road today with EVs and the electric grid wouldn't feel it from a capacity standpoint (ie, no new coal/nuclear/hydro plants needed).

Throw in some of the proposed "smart grid" enhancements where the electric grid has some leeway to manage how EVs charge/discharge and things are even rosier. (These proposals include the idea of allowing the grid to balance overall demand by balancing EV demand more directly. This includes "pausing" EV chargers during demand spikes and even potentially "loaning" power back from the large batteries of EVs to meet those spikes, repaying that power when demand drops again.)