How far can we stretch a gallon of gasoline? OK, maybe it isn't a question for the ages. But with oil setting new records at more than $60 per barrel, it seems like a good time to ask. And considering that the U.S. economy is hooked on oil imported from political nightmares such as Nigeria and Saudi Arabia, and that our petrodollars support regimes that indulge Islamic radicalism, and that global warming threatens to turn Orlando into beachfront property . . . well, maybe it is a question for the ages.
The answer: It depends. Last month at the Society of Automotive Engineers' Supermileage competition in Marshall, Mich., a team from Mater Dei High School in Evansville, Ind., got 1,836 miles per gallon. However, the winning vehicle carried only one passenger--a skinny kid--at just over 15 mph, and it looked like a body bag on wheels.
Slightly more practical, DaimlerChrysler last month unveiled a concept vehicle called the Mercedes-Benz Bionic Car, a lightweight, streamlined four-seater whose biomorphic design is based on the tropical boxfish. Powered by a small diesel engine, the bait-shaped runabout gets 70 mpg (diesel fuel, it should be noted, has more energy content than gasoline and some emissions issues that gasoline doesn't have).
Among street-legal cars, the Honda Insight--another aerodynamic guppy and the first (1999) hybrid gas-electric vehicle sold in the United States--is the gas mileage champion, getting 60 mpg in the city and 66 mpg on the highway.
And then there's the car I'm driving: a Toyota Prius jury-rigged by a couple of wildcatting engineers in Monrovia. Equipped with an oversized battery, a home-built battery controller (and lots of home-built computer code) and a battery charger, it's a plug-in hybrid electric vehicle, or PHEV, a technology that might just represent one of the most dramatic advances in fuel stretching since the Pennsylvania oil fields. And not a minute too soon.
The idea is that owners charge up the car overnight, plugging into their garage outlet for cheap, off-peak electricity, and the stored energy covers their short-range daily driving--on average, less than 30 miles. Except that, unlike electric-only vehicles, which can range only as far as a charge allows, PHEVs can fall back on a gas engine. Within its electrically boosted range, this car can get 100 mpg.
Or more. A lot more, if you believe a growing chorus of PHEV partisans, some of whom are famously hard-nosed conservatives born again as energy evangelists. PHEV technology has earned a rousing endorsement from the bipartisan Commission on National Energy Policy. Former Secretary of State George Shultz and former CIA director R. James Woolsey, co-chairs of a dire-sounding organization called The Committee on the Present Danger, wrote in a policy paper last year: "A plug-in hybrid averaging 125 mpg, if its fuel tank contains 85 per cent cellulosic ethanol, would be obtaining about 500 mpg [of gasoline]. If it were constructed from carbon composites the mileage could double. . . . What are we waiting for?"
Setting aside the mysteries of cellulosic ethanol and carbon composites for the moment, the idea that PHEVs can be built from off-the-shelf parts has become something of an orthodoxy. "The solution is already with us," wrote Newsweek International columnist Fareed Zakaria in March. "We don't need to reinvent the wheel or wait for sci-fi hydrogen fuel cells," New York Times columnist Thomas Friedman wrote in late June. "The technologies we need for a stronger, more energy independent America are already here."
Not so fast, says Dave Hermance, an executive engineer of Toyota and the company's guru of all things Prius. Somewhat ruefully--he isn't very happy about people hacking his beloved and delicately engineered Prius--Hermance says that while the PHEV concept has merit, it won't work with the current generation of lithium-ion batteries, which, while powerful, are both too expensive and temperamental for use in mass-production cars. Depending on their chemistry, lithium-ion batteries tend to get really hot--thermal runaway, it's called--and, as the military well knows, to ignite. "The betting line of developers is that a lithium-ion battery of sufficient cost, durability and safety is three to five years away."
Hermance isn't alone. Dr. Dan Doughty, an expert in battery technology at the Department of Energy's Sandia National Laboratory in Albuquerque, N.M., thinks high-performance lithium-ion batteries are still too buggy to warrant exuberance. Doughty also notes that electric vehicle backers' claims of super-high mileage often do not include the cost of electricity as well as gasoline. "What chaps my hide is when people know better and hold back some of that information," he says.