When Chevrolet announced that the upcoming plug-in hybrid Volt will get 230 mpg, many media outlets (including Fast Company) responded with uncertainty. After all, there isn't an official way to quantify mpg with plug-in hybrids—the EPA is still working on that—so how can the claim be confirmed? Perhaps this uncertainty is what spurred Fisker to make a much more reasonable claim for the Karma plug-in hybrid, which gets 67.2 mpg according to a calculation system developed by the Society of Automotive Engineers.
The 2010 Karma, scheduled to debut at next week's Frankfurt Auto Show, will sell for $87,900 thanks to an ultra-pricey lithium-ion battery. It could be worth it for car nuts who appreciate the vehicle's ability to rev up from zero to 62 in six seconds, but the Volt will sell for a relatively cheap $40,000 and go from zero to 60 in approximately 10 seconds.
It's possible that Fisker is underselling the Karma's abilities—the company ultimately expects the car to get a confirmed rating of 100 mpg or higher—but until the EPA releases official mpg quantification methodology, it's all guesswork. So we have GM claiming 230 mpg for the Volt, Nissan offering up a 367 mpg for the Leaf, Tesla guessing that the Roadster gets 135 mpg, and now Fisker giving the most conservative rating yet at 67.2 mpg. That's still impressive, to be sure, but Fisker might want to consider upping its estimates if it wants to keep up with the hype surrounding the Volt's campaign, which features posters announcing the 230 mpg rating plastered on buildings across the U.S.