You may have seen the city's cars around town, painted with an eye-catching claim on the rear bumper: "This plug-in hybrid gets 100+mpg."
Also, a greener boast: "150+City MPG!"
Not exactly, it turns out. Not even close.
Try 51 miles per gallon, city and highway combined. Not counting the cost of the electricity.
It's what 14 plug-in Priuses averaged after driving a total of 17,636 miles. The pilot project is one of the few in the nation to subject plug-in hybrid cars to regular motor-pool duty, as opposed to being driven by hypermilers or alt-energy enthusiasts.
"We're not putting these cars on a test track," said Scott Thomsen, a spokesman for Seattle City Light, which has three of the plug-ins. "We've got them on hills and wet streets, in the cold and the hot, on short trips and long — all the conditions that real people deal with every day."
Getting 51 miles per gallon sounds fine compared to most gas cars. But it's a black eye for a technology that trumpets it will get twice that. And which doesn't pencil financially unless it hits at least 80 miles per gallon.
....The problem is the extra battery costs $10,000. At 51 mpg, the plug-in saves only about $200 in gas costs annually compared to a regular Prius in the city's fleet (and that's at $4 a gallon.) It would take 50 years to make back the cost of the extra battery.