Plug-in cars sparking a power shift

PHEVolution at work
The behavioral changes sparked by plug-in vehicles were on full display during last week's test drive with Feldman. Every move was as gradual as possible — including his smooth acceleration to blend into freeway traffic, even when a cement truck was coming up close behind.

Studies have shown that less aggressive driving is one of the biggest factor behind better fuel economy — not only for PHEVs and other hybrids, but for traditional gasoline-powered vehicles as well. Punching on the accelerator uses up more spurts of gasoline than gently getting up to your cruising speed.

"The smoother you are, the better off you are," Feldman explained.

The big difference for hybrids — and particularly for the V2Green-equipped PHEVs — is that the miles-per-gallon readings are continuously on display. Even if you're not reading the numbers, you know that someone else is. For example, Francfort could check a GPS display on his office computer in Idaho to check on Feldman's mileage performance in Seattle, and even see which lane on I-5 he was driving in.

"How am I doing?" Feldman asked Francfort over a speaker phone. "Do I have a lead foot?"

"No," Francfort answered. "I think 106 miles per gallon is not so bad."

Feldman was getting that kind of mileage because much of the power was coming from the Hymotion lithium-ion battery that was installed in the Prius' trunk, at a conversion cost of roughly $10,000. The extra electrical boost means the car's gasoline engine comes on less frequently, at least until the batteries run down.

Sweet spot for electric power
Feldman, who drives a standard-issue Prius when he's off-duty, said he can notice a difference between his own car and the city-owned PHEV when he drives up an incline. The PHEV could take an uphill access ramp without a single gasoline-fired boost. "In my car, I cannot do this," Feldman said.

PHEVs don't give you much of a fuel economy advantage for a trip around the block, because the gasoline engine has to be fired up at first to warm up the catalytic converter. And the all-electric advantage fades away on an extended trip when the batteries run out. But for a medium-length trip, a PHEV is just right.

For example, on the 18.3-mile trip out from West Seattle across Lake Washington to Redmond, Feldman hit a fuel economy mark of 108 miles per gallon by using just 0.17 gallon of gas. By that time, however, the batteries were drained to 11 percent of capacity. The 13.3-mile trip back to downtown Seattle used up 0.22 gallons of gas, resulting in a 60-mpg performance.

When V2Green's software added up all of that day's trips, the distance driven came to a little more than 40 miles. That used up half a gallon of gas, which translates to 81 miles per gallon. Total cost, including the price tag for 3.98 kilowatts of electricity: $2.91.

That's the kind of real-world data that the Idaho National Laboratory hopes to pile up over the next year or so. As a result, carmakers may find it worth their while to build additional intelligence into future electric vehicles. Utilities just might enlist smart-charging technology and incentive programs to accommodate a new wave of drivers. And drivers could be using new gizmos to save money at the gas pump — and on their electric bill.

It might even be fun.

"This is the next level up," Feldman said, pointing to Clark's laptop. "People are really going to get into computer-game mode in terms of seeing what they can do."

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