With big pushes from GM, Ford and Toyota, plug-in hybrids are back in the spotlight, but lurking in the shadows is the same old problem: building a lightweight, powerful, affordable battery.
Jim Motavalli - Popular Mechanics - March 2007
The Chevy Volt concept car has a 110-volt charging port on both sides of the front fender. It takes 6 hours to charge, and can travel 40 miles before burning gas.
When General Motors unveiled the Chevy Volt in January, plug-in hybrids suddenly seemed to matter again. Sure, the Volt is a concept car, and more of a testbed for various electric-drive systems than a showcase for plug-in charging. And the aftermarket kits that turn a Toyota Prius into a plug-in have been around for years. But with GM planning to build two plug-in vehicles the Volt, as well as its next Saturn Vue Green Line - this technology is looking like the biggest thing since, well, hybrids.
How do plug-in hybrids work?
Their batteries can be recharged either by the vehicle's gasoline engine or the electric grid. A plug-in's batteries are usually lithium-ion, which are more powerful than a standard hybrid's nickel-metal-hydride batteries, but need to be plugged in for hours to fully charge. When the charge is depleted, the plug-in runs like a standard hybrid.
How energy-efficient are they?
Fully charging a kit-modified Toyota Prius adds around 50 cents to an electric bill, and the car has a battery-only range of 31 miles. Then the gas engine kicks in. Even so, a 100-mile trip burns just over 1 gal. of gasoline. Sounds like a bargain - but keep in mind, the warranty-voiding kits cost up to $10,000.
Why aren't plug-ins in production?
Automakers cite the high cost of lithium-ion batteries. Ford and Toyota have announced active interest in plug-ins, but for now they are sticking by their hybrids. DaimlerChrysler is currently testing a plug-in hybrid version of its Sprinter delivery van. Progress, maybe, but no one's making production commitments. GM has taken the biggest leap, awarding contracts to battery makers to produce lithium-ion packs for its Saturn Vue Green Line. The more radically designed Chevy Volt - which has a gas engine that recharges the batteries, and never powers the wheels - will have to wait. It needs a 400-pound battery, which GM estimates won't be feasible until 2012 at the earliest.