Plug-In Hybrids: Ready For Prime Time?

Optimistic predictions for plug-in hybrid-electric vehicles abound. Advocates of plug-ins (also called PHEVs) say they promise to radically reduce U.S. dependence on foreign oil, slash greenhouse gas emissions and radically cut the cost of running a vehicle. A study by the Electric Power Research Institute and the Natural Recourses Defense Council said plug-ins will cut U.S. petroleum use by up to four million barrels a day: The groups predicted it will be as if 80 million cars were removed from the road. Several automakers announced that they would offer plug-ins for sale by 2010. Advocates predicted that two-thirds of all vehicles—including larger delivery trucks—would be plug-in hybrids. Plug-ins will save money and the environment while protecting our national security, said the prognosticators. (A definition: Plug-in hybrid-electric vehicles can tap into household electric outlets to recharge their batteries. They retain conventional gasoline engines to allow longer journeys. Some call them “extended-range electric vehicles.”)

Current Problems
However, some doubts have emerged. Those who lack three-car garages wondered where they would find electric outlets. Many asked if electricity from coal-fired powerplants would be cleaner than that produced by the gasoline engines in current (non-plug-in) hybrids. Others asked if electric utilities would be able to meet the demand, noting that extra requirements from plasma televisions surprised the utilities, and plug-ins will use far more electricity. Some noticed that plug-in hybrids might go less than a dozen miles on electricity alone, especially in freezing weather or at speeds greater than 35 mph.


Even under the best conditions plug-ins won’t go much further than 40 miles with engaging the gasoline engine. Toyota said the first plug-in version of its Prius would be available only to fleet users such as businesses, utilities, government services. General Motors said its Chevrolet Volt would cost more than $40,000—steep for a family sedan—and be available in very limited numbers. All research and development funding came under scrutiny after the sales disaster of late 2008. A closer look at predictions for energy savings and pollution reductions of plug-ins revealed optimistic assumptions about how electricity would be generated and when plug-in owners would recharge their vehicles’ batteries. Some automakers revealed pessimism about when lithium-ion (li-ion) batteries, crucial for the success of plug-ins, would be ready for mass production. They also were concern if li-ion batteries would meet the 150,000-mile or 10-year reliability standards set by law in more than a dozen states. Even if the assumptions were correct, many of the predictions were not for 2015, but rather 2050.

Positive News
This isn’t to say that plug-in hybrids won’t eventually be a significant part of the automotive market and help minimize both pollution and petroleum use. But the real contribution might not happen for at least a decade. “It’s quite another thing to mass-produce (plug-ins) in a way that will allow us to be sure they’ll be reliable over the long haul of a PHEV’s service life,” said a Toyota spokesman. “That’s why we’re going slowly and carefully.”


Optimists point at aftermarket kits that allow current hybrids to be converted into plug-ins. These provide extended electric-only range by adding batteries. These added batteries are more fully charged and drained than the original-equipment hybrid batteries. However, battery life is significantly reduced if charged more than two-thirds of full capacity or drained below about 40 percent. We found no aftermarket conversion companies that offer even one-third of the 150,000-mile or 10-year warranty required of automakers. Also, even the most optimistic estimate of electric-only range was only about 40 miles. Some say electric-only range might be just 10 miles.