I did a back of the envelope calculation some time back for both Canada and the UK (I imagine the US numbers are proportionally similar to Canada). If we replace all private passenger cars with EVs, using average mileage, it increases annual electricity demand by about 20%. The difference between daytime peak and nighttime off peak is more than 20%. In a lot of cases, there will be no need at all for new power plants or distribution networks. The reality, of course, is more complicated as we are electrifying much more than passenger cars.

You better believe, however, that the distribution networks are planning around this. I was in a meeting with someone from the National Grid (UK central grid authority) who is responsible for planning for the transition. Basically, all new housing developments are being provisioned assuming heat pumps and EV chargers. Existing areas are being monitored and upgraded as they near the grid limits. Plans go out years in advance. It is a lot of work, but I am confident that it is being well managed. I cannot say that everywhere is as well managed, but I think it is safe to assume that many of these people and organisations do, in fact, know what they are doing. It sounded like the biggest problem in the UK was NIMBYs fighting against the new distribution networks needed to land the power from the offshore wind farms which are rapidly replacing the old fossil fuel generators.