Plug-In Hybrids: More Hype Than Hope?
By Scott McCredie 18 hours ago
Seattle Mayor Greg Nickels speaks at the unveiling of one of the plug-in hybrids the city added to its fleet last year. Although advocates say the cars can deliver triple-digit fuel economy, those in Seattle's test fleet are actually averaging about half that, leading some to question the technology.
Seattle has outfitted more than a dozen Toyota Prius hybrids with new plug-in technology to squeeze even better fuel efficiency from the eco-wonder.
City officials were intrigued by data suggesting they could cut their fuel consumption in half by using batteries charged directly from the grid. If claims are to be believed, drivers would routinely see 100 mpg using readily available battery packs installed in the trunk.
Just over a year after performing the conversions, the city says it is thrilled with the cars. The plug-in Prius hybrids have used less gas and emitted less CO2 than their conventional counterparts. But the tests also have put a big dent in the plug-in promise.
Having racked up some 17,000 miles, the plug-in Prius hybrids are averaging just 51 mpg. That's raising uncomfortable questions about the value and effectiveness of plug-in technology, even as President Obama pledges to have 1 million of them on the road by 2015.
"Getting 51 miles per gallon sounds fine compared to most gas cars," railed Seattle Times columnist Danny Westneat. "But it's a black eye for a technology that trumpets it will get twice that."
Greentrepreneurs routinely cite 100 mpg as the new benchmark for eco-conscious drivers, and even Wired magazine touted the figure in a cover story last year. But it's more than a psychologically comforting number. It's a figure we can achieve with current technology, proponents argue. Even President Barack Obama became a cheerleader when he recently told Jay Leno on the Tonight Show that "it's spectacular what is being done now with plug-in hybrids. And potentially we could see cars getting 150 miles to a gallon of gas."
Such claims are not exactly false: Careful drivers have achieved 100 mpg behind the wheel of plug-in hybrids. But the Seattle fleet test, and others like, suggest that "real world" may be far smaller. The results may in part highlight industry hype, but more significantly they point to the many non-technological factors that come into play in wringing better fuel efficiency from plug-in hybrid cars, most notably driver behavior.
Seattle has racked up more than 17,000 miles testing 14 plug-in hybrids in the past year. The fleet has averaged 51 mpg, a figure that critics say a joy-riding teen with a lead foot can do in a conventional Prius. Idaho National Laboratory is seeing similar results among the plug-in fleets it is monitoring nationwide.
"It sounds like they're not plugging them in," said Paul Scott, a founder of Plug-In America. "I don’t know how you would drive one and get such bad mileage."
It's an important question, because General Motors and Toyota are among the automakers promising to have plug-ins on the road as early as next year. The results of these early fleet tests suggest EV advocates and automakers will have to tell people how to drive the cars most efficiently because they may not catch on if consumers don’t see the fuel efficiency they’re promised.
"This is a very sensitive time for plug-in hybrid technology," says Ric Fulop, founder of A123 Systems, which manufacturers the Hymotion plug-in conversion system that the test fleets are using in the Prius.
Plug-ins improve upon the fuel economy and low emissions of conventional hybrids by relying more heavily on electricity to get around. You can recharge the batteries from a wall socket and get as many as 30 miles on a charge if you keep it below 35 mph. At higher speeds, the electric motor assists the gasoline engine, delivering 100 mpg or more.
So far the only way to get one has been to pay someone to convert your hybrid. That can costs as much as $10,000 or more, and so far only hardcore advocates and early adopters have taken the plunge.
Seattle decided to give the technology a try in March 2008 after the U.S. Department of Energy agreed to subsidize the program. The city, which maintains a fleet of 300 conventional Prius hybrids, converted 14 of them to plug-ins. They're used by a host of municipal and county agencies, which have the cars in their general motor pools or assigned to specific employees.
The city and Idaho National Laboratory have closely monitored how the cars are used and what sort of fuel economy they’re getting. At first glance, the 51-mpg average appears lackluster. A 2009 Toyota Prius is good for 46 mpg, according to the Environmental Protection Agency, and it isn’t unusual to get 60 or even 70 mpg in one. Still, city officials put a positive spin on the results.
"You have to be impressed with what you're seeing," said Scott Thomsen, a spokesman for City Light, a utility that has added several plug-ins to its fleet. "Sometimes drivers are getting 100 mpg in a stretch. This shows what the vehicles can do in real world driving conditions, not a test track in the middle of Arizona with consistent conditions."
Thomsen notes the plug-ins are outperforming the city's conventional Prius hybrids by at least 11 mpg, so they're emitting about 25 percent less CO2.
Idaho National Laboratory is seeing similar results with the 104 plug-in hybrid vehicles it is monitoring in 22 states. The cars have logged more than 300,000 miles in the past year and returned an average of 46 to 51 mpg, said Jim Francfort, principal investigator for advanced vehicle testing activities at the lab.
To be fair, you can get triple-digit fuel economy in a plug-in hybrid. James Morrison, a Seattle-area entrepreneur and EV enthusiast, let me take his plug-in for a spin. He spent a $10,000 to have a local firm install a Hymotion system in his 2009 Prius, which sports a license plate reading "MPG-XXL."
As I get in, he proudly notes that he's already gone 479 miles and barely put a dent in the tank. So far he's getting 99.9 mpg. He resets the trip computer and we set off through downtown Bellevue, and then roam the suburbs. Peeking at the fuel economy gauge, I see we’re getting between 100 and 160 mpg. It’s exhilarating. Merging onto Interstate 405, I hit the gas and cruise for several miles. The fuel economy dips into the 60s. Still, by the time we pull into Morrison's driveway, I’ve averaged 115 mpg.
So what gives with all these fleets struggling to get half that?
EV advocates have a simple answer – the drivers aren’t being told how to maximize fuel efficiency, and they’d don’t care because they aren't paying for the gas.
To get the most from plug-in hybrids, EV advocates say, you've got to us a light touch on the accelerator, mind your speed and plug it in at every opportunity to keep the batteries fully charged.
"Drive impact is really huge," said Francfort. "Aggressive driving effects the mileage of all cars, but with plug-in hybrids there’s more of an impact."
Keeping the cars charged is also key. If the battery runs down, the gas engine must work harder – the battery becomes dead weight – and that cuts efficiency. Seattle officials discovered the plug-ins were tooling around with dead batteries nearly one-third of the time. The cars with fully charged batteries got 50 percent better fuel economy than those with dead ones.
That highlights another issue: The widespread infrastructure needed to keep plug-in hybrids and the electric cars most automakers are working on doesn't exist yet. Startups like Better Place, Coulomb Technologies and Ecotality are working on it with help from automakers like GM and Nissan. In the meantime, drivers like Morrison say they ferret out electrical outlets in parking garages and behind buildings so they can plug in as often as possible.
EV advocates are quick to note the Prius wasn't designed to be a plug-in hybrid, and in fact makes a lousy one. The biggest problem is the electric motor is too small, so the car relies more heavily on the gasoline engine. Cars designed from the ground up to be plug-in hybrids, like the plug-in Prius that Toyota is working on or the Saturn Vue plug-in – will almost certainly offer far better fuel efficiency.
Plug-in advocates say Seattle's fleet results are no reason to pull the plug on the cars. The technology is sound, they say, and it will deliver spectacular fuel economy - but only if people are told how to get the most out of cars with cords.
"I agree with anyone who says 100 to 150 mpg is out of line," says Dan Davids of Plug-In America. He was among the first people to convert his Prius with a Hymotion kit, and he’s averaged 75 mpg. "That’s been hyped too much. But we shouldn’t indict the technology. It’s a people problem."
