You can make a couple of arguments here. Some energy can be generated by capturing diverted energy when the driver brakes -- not an engineer, so can't describe that well, but I think it can be done.
You can generate some of the power from solar or wind farms. Or generate it from your solar-paneled roof or garden wind turbine. Frack a gas well and run your own generator. Realistically, though, how much electricity can you get that way?
Yes, you save on fuel made from imported petroleum. If everyone bought an electric car.
This sounds like alternative-energy bashing, which it's not. It's bashing promoting a let's-pretend world. Maybe burning coal or natural gas is the right way to fuel mobility, but if it is, let's be clear that we are making that choice.