Hybrids like Toyota's Prius and plug-in vehicles such as the Chevrolet Volt run on systems other than purely gas-fired engines. The systems, or powertrains, that drive the so-called greener cars use electricity generated by batteries and electric motors to either supplement or largely take the place of internal-combustion engines. The Volt: The Chevrolet Volt, billed as a rechargeable electric car, gets most of its power from an electric motor and a battery pack with a 40-mile (64-kilometer) range. It also has a small internal-combustion engine that kicks in after the battery runs out of juice. The Volt's battery pack can be recharged from a standard home outlet. Traditional hybrids: The Volt's mileage could be a vast improvement over that of traditional hybrids, such as Toyota's popular Prius, which combines an internal-combustion engine with a special hybrid battery that boosts fuel efficiency. u The newest version of the Prius starts at about $22,000 and gets an EPA estimated 51 mpg (21 kpl) in the city and 48 mpg (20 kpl) on the highway. u Other hybrid models use different forms of powertrain technology and don't achieve the dramatic jump in mpg that the Prius does. For example, the Chevy Malibu hybrid, which starts at $25,555, gets up to 26 mpg (11 kpl) in the city and 34 mpg (14 kpl) on the highway. u By comparison, the purely gas-powered Malibu, priced at $21,605, gets up to 22 mpg (9 kpl) in the city and 33 mpg (14 kpl) on the highway. Decision: With a nearly $4,000 premium on the hybrid model, consumers need to consider fuel prices, along with how much they plan to drive the vehicle, in deciding whether the extra cost is worth it. All electric: The Volt is expected to compete against high-end electric vehicles, such as the Tesla Roadster, which has a range of 224 miles (360 kilometers), but also comes with a $100,000-plus price tag. Tesla is also working on an electric family sedan that will be priced considerably less.
