Autos

Chevrolet Volt

Auto show debut: Detroit, January
What's different about it: Plug-in hybrid powertrain

Since its auto show debut, the Chevy Volt has attracted a lot of criticism for the fact that there are no practicable lithium-ion batteries, which are necessary to make it work. GM says it hopes to have them by 2010 to 2012. The Volt is a "plug-in" hybrid — its batteries can be recharged by plugging them into a socket. That cuts tailpipe emissions compared with conventional gasoline-electric hybrids, which use a gasoline engine to recharge the battery (plus some energy that is recovered when braking). Mark Vann, GM's program manager for fuel cell activities, said the Volt is also significant because it is the first car built on what GM calls its "E-flex" platform. That means the Volt can accommodate either the plug-in hybrid or a hydrogen-powered, fuel-cell drivetrain, which is also in development.