I can offer a little insight as I am a senior executive at an electric utility, and have been active in the so-called "smart grid" and EV areas, including with other utilities and regulatory/government entities.
The bottom line is that electricity is usually locally produced and delivered by members of the community, and the economic benefits of using the electricity stay in the community/state/province more so than with fossil fuels. As such, electric utilities are very interested in supporting the adoption of electric vehicles. Utilities in my jurisdiction have been compelled to support energy conservation and demand management for about 10 years now, but that was to initially address a shortfall of generation capacity (and not for environmental reasons as many had assumed). A combination of the economic downturn in 2008 (loss of manufacturing companies) and the refurbishment / installation of new generation assets has largely removed that impediment. The biggest driver of conservation now is the rising cost of power. In my jurisdiction, some of that rising cost is associated with a move to more renewables, but the majority of the blame goes to dealing with policies of the past that buried costs and artificially kept costs low... largely for political reasons.
There have been a number of impact studies done, and for the most part there is plenty of capacity for electric vehicles. If/when demand grows, the increased sales will support the addition of infrastructure just like it did when air conditioning became more prevalent in the '60s and '70s. The biggest bottleneck is at the local distribution level, in particular the distribution transformer feeding (typically) 6-10 houses on a street. The primary system feeding the transformer will typically have capacity as will the conductors in to the home/business which are sized to the main disconnect's capacity. Transformers, on the other hand, are sized to the typical load they supply. With diversification, a group of homes may only be using a small fraction of their capacity at any given time. Plug in an EV (a Tesla may consume the equivalent of 4 homes) which consumes power continuously and the transformer may become overloaded. Nighttime charging doesn't always help as utilities often count on lower loads and cooler temperatures at night to reduce the transformer's operating temperature.
Multiple EVs on the same local system could present problems in larger numbers. This is where creative "demand response" systems could help by scheduling when cars charge so that all are not trying to draw power at the same time.
