FRANKFURT  The electric car is at the starting line, and the gun is about to sound.

Now automakers must prove that the technology, and the market, are ready.

After years of talk and prototypes, some automobile makers believe the electric vehicle is about to become more than just a science experiment.

The French company Renault will unveil a lineup at the Frankfurt motor show this week that includes a purely electric sedan, without a backup internal combustion engine. Renault says the vehicle will be in showrooms by 2011.

General Motors, which recently emerged from bankruptcy protection, is offering the Chevrolet Volt as one of its comeback cars. The Volt is an electric vehicle with a backup gasoline-run generator for longer trips.