What is Range Anxiety?
Bob Lutz, the Vice Chairman of Global Product Development at General Motors and one of the people responsible for the Chevy Volt range extended electric car, likes to tell an anecdote about the time he ran out of juice on his electric scooter. He had to call a friend who came with a big pickup truck to get Mr. Lutz and the electric scooter ("Not very green," he says).
That's exactly what range anxiety is in the context of an electric vehicle. It's the fear that one day you're going to find yourself somewhere that is too far from your home (so you can't just go back and plug in), yet far from known charging stations, or if you are close, you just don't have the time in your schedule to stop for a long time to allow the battery to recharge.
This is the main reason why the Chevy Volt is a range extended electric car; this means that it carries a gasoline engine to act as a generator when the battery runs out. As long as you have access to a gas station, you can drive around (but this has some downsides -- a gas engine is heavy to carry around and adds complexity to the drivetrain).