The vast majority of people will usually charge overnight and don't need to regularly charge at peak times. Through intelligent charger management, you can distribute the load of charging across the entire off-peak period. The UX for this can be fairly straightforward - by default you charge at the cheapest rate, or you can press a button to get the quickest possible charge.
The real dividend comes from bidirectional charging, using the collective resources of plugged-in cars as a load balancing reservoir. In exchange for a discount on your electricity, the grid can take a small percentage of your EV's battery capacity when needed. A typical mid-range electric car has a 40kWh battery, which represents about four days of electricity consumption for a typical European household.
Nissan and the British utility regulator ran a two-year trial to examine the long-term impact of EVs on local grid infrastructure. The trial used intelligently-managed unidirectional charging. They concluded that about 32% of local electricity circuits will need to be upgraded by the time that EVs represent a majority of vehicles on the road. This figure could potentially be lowered further by bidirectional charging technology.
America still has huge potential for efficiency savings, because of the immensely high average household electricity consumption. The average American household uses nearly three times as much electricity as the average European household. Air conditioning is only a small part of this disparity, representing about 18% of the electricity consumption of American households according to the Energy Information Administration.