The Age of 200 to 300 MPG Is Almost Here



General Motors and Nissan traded barbs this week over which of their new green-tech cars will get the best gas mileage. GM began the war of words by claiming that its Chevy Volt, a plug-in hybrid that goes on sale late next year, will achieve a whopping 237 miles per gallon in city driving. The Japanese automaker responded, saying that its new Nissan Leaf, an all-electric vehicle to be introduced in 2012, will zoom in at 367 mpg, and will be significantly cheaper than the $40,000 Volt. Although both mpg numbers are a bit misleading, there is no doubt that the age of incredible gas mileage is nearly upon us.

First the Volt. The plug-in is powered by an electric motor during city driving that has a range of 40 miles. That will mean for some incredible gas mileage around town and will make the 237 mpg figure easily attainable. However, once you go beyond 40 miles, then the Volt will revert to being a regular gasoline-powered car, and probably will get no better than 30 or 40 mpg.

The Leaf, by contrast, is powered by an all-electric motor, and does not have a gasoline engine to back it up. But it has a larger battery that will allow it travel up to 100 miles before needing a charge. One drawback of the Leaf, however, is that it can take up to 16 hours to fully recharge the car's battery. So why does an electric car get any "miles per gallon" when it uses no gas at all? The 367 mpg for the Leaf refers to the gasoline equivalent needed to recharge the battery with electricity.

Regardless of the caveats, both cars have the potential to be global-warming game-changers - especially in California, since we don't depend on coal power for significant amounts of electricity. On the other hand, in states that depend heavily on coal, regular hybrids, such as the Toyota Prius, which do not require battery recharging, are still the better choice to reduce greenhouse gas emissions.