The Volt uses electricity to move at all times and speeds. For trips up to 40 miles or 64 km, it is powered only by electricity stored in its 16-kWh, lithium-ion battery pack. When you’re on the move and the battery's energy is depleted, a gasoline/E85-powered engine (GM hasn’t given out any specific details yet) kicks in providing electricity to power the electric drive unit and to simultaneously charge the battery.
The driver can also charge the Volt’s batteries by plugging it into a standard household 120v (8 hours) outlet or use 240v (3 hours). GM estimates that the cost for charging the batteries is about 80 cents (10 cents per kWh) for a full charge that will allow the driver to use the car for up to 40 miles.
Video II: Chevrolet Volt Interior Shots