Electric vehicles, as good as good at they are at conserving scarce resources, has a well-known shortcoming: they can only be driven short distances. For example, the Chevrolet Volt has only a maximum range of 80.5 kilometers (50 miles) on a single charge. And, while it is possible to use fossil fuel to back up the car’s electric system, that takes away the point...

General Motors (GM) unveiled the Cadillac ELR Coupe, its first luxury electric vehicle. It is GM’s second extended-range electric vehicle and the third extended-range vehicle unveiled in the past month. The Cadillac ELR is a plug-in hybrid car that uses technology that is similar to the Chevrolet Volt that was released last year. “The concept generated instant...