That may depend on where you live, and what your electricity consumption already is. In CA, for example, with our tiered billing and PG&E's award-winning business practices, it's pretty easy for an electric car to rack up quite an energy bill. If you were already using electricity up to the top of your tier, the add for the car will be at $$$ rate.

So they also have non-tiered plans for electric car owners but those are time of use. If you use them at peak for whatever reason, $$$ again. It's a little tricky.

It won't be as expensive as liquid fuel, to be sure, but the savings over time might not be as high as you'd expect. Offsetting with solar seems to be the popular option around San Jose, where homeowners tend to be particularly affluent.