What is it?
Any car with a battery-powered motor—including every variety of hybrid—is an electric vehicle to some extent. A pure electric vehicle would be run entirely by the battery-powered motor.
What's good about it?
As with plug-in hybrids, electric vehicles could be cheap to fuel, given the relatively low cost of electricity drawn from the power grid through an ordinary outlet. Power drawn overnight at off-peak rates could cost one-fourth the equivalent of gasoline.
What's bad about it?
The batteries required for an all-electric vehicle would be even bigger than those needed in a hybrid—so big that the car would need to be designed around the battery. For now, they'd be very expensive, too.
Where would it be most useful?
They'd make most sense for commuters and others who typically drive short distances. Once the battery charge is depleted, there's no real advantage to an EV—since it has to run on a gas engine or some other power source.
How much will it cost?
The electric-powered Chevy Volt, due in 2010, will have a price tag of about $30,000—with GM most likely subsidizing the battery pack. Fueling it from home, however, could cost 80 percent less than filling a car with $3 gas.
When's it coming?
GM built an electric car in the 1990s—the EV1—that flopped because it had limited range, with no backup engine, and carried just two people. Tiny Tesla Motors is building a $100,000 all-electric car, due in 2008, using several thousand laptop-style lithium-ion batteries strung together. Stay tuned.
What's taking so long?
The batteries. An EV battery pack must be able to withstand thousand of deep charges and discharges. Lithium-ion batteries like those used in laptops, cell phones and power tools have the most potential—but nobody's mass-produced one big enough to power a car safely and reliably.
Who's doing it?
GM has the most at stake, with multimillions of research dollars—and its credibility—committed to delivering the Chevy Volt by 2010. Toyota and other carmakers are also doing extensive battery research, as are battery suppliers.
Could it be a silver bullet?
Researchers have their fingers crossed. If the battery technology matures, lithium-powered electric vehicles could be a game-changer, with great driving characteristics, low tailpipe emissions, and super cheap fuel. But big backers like GM. have guessed wrong before.