Road-Testing Cars of the Future

If, by chance, you're heading to the Alternative Fuels and Vehicles conference in Orlando in April, bring your lab coat and goggles. There will be a biodiesel exhibit, a "summit" on fuels produced with algae, and seminars on propane, natural gas, and biomethane. And if you thought hydrogen was the holy grail of fuels, guess again: This year, it's battery power.

Ever since the automobile displaced the horse and buggy a century ago, almost all cars have run on fuel derived from oil. But a new revolution is underway, and this time, it's the fuel that's poised for a makeover. At this year's Detroit Auto Show, auto execs who used to rhapsodize about hood scoops and horsepower enthused about emission-free tailpipes and energy independence. General Motors is staking its resurgence on a battery-powered car that plugs into a household receptacle. Other big automakers are seeking the same kind of killer app that Toyota found when it introduced the Prius hybrid almost 10 years ago. "This is about the new DNA of the automobile," says Larry Burns, GM's research and development chief. "The recession and its impact on the auto industry amplifies the need for a diversification strategy."

[See the pros and cons of 8 green fuels.]

There are a lot of compounds besides gasoline that are capable of powering a car, and government subsidies have spurred the adoption of a few, including corn-based ethanol in the United States and diesel in Europe. But gasoline has prevailed because it still offers power and convenience at a lower cost than almost anything else.

That equation obviously shifted for a while last year, when gas prices in the United States crested at $4 per gallon and buyers fled big vehicles. Although pump prices have drifted back below $2—partly because of the global recession and slack demand—automakers are planning for a future in which gas once again hits $4 and then goes higher. Other factors are working against gasoline, too: discomfort over imported oil, concerns about global warming, and technological advances that could make alternatives cheaper.

So, for the next decade or so, there will be a worldwide energy derby as the backers of half a dozen plausible fuel systems battle one another for prominence under the hood. But vehicle design and infrastructure needs will eventually coalesce around one or two winners to take advantage of high-volume production, which is essential to lowering costs.

[See the 12 most important cars of 2009.]

Ethanol and other biofuels are appealing because they'd require only modest modifications to today's internal combustion engines. But so far, biofuels don't seem to represent the dramatic leaps in energy efficiency—or the sweeping transformation of the automobile—that many engineers think is possible. If an automotive revolution arrives, it will probably be powered by hydrogen or electricity. Engineers still have several puzzles to solve, like dramatically lowering cost, getting the fuel to consumers, and determining the best way for it to power the wheels. The following prototypes and early production vehicles demonstrate the most promising alternatives to gasoline. Their success or failure will help determine the kinds of cars Americans are driving a decade from now.

Honda Clarity. This road-ready prototype gets the equivalent of 74 miles per gallon, with good performance and no tailpipe emissions. Here's how: Hydrogen stored in a tank mixes with oxygen in a "fuel cell" about the size of a carry-on suitcase that functions as an onboard power plant. The electricity it produces powers a motor that spins the wheels, while a lithium-ion battery kicks in every now and then to supplement the car's power, just as in a hybrid. The powertrain is novel, yet the driver presses the pedals and turns the steering wheel the same as in any other car. "Honda brought in clean technology without changing the way driving feels," says Jack Cusick, an assistant principal in Orange County, Calif., who is one of about 200 drivers who will participate in a prototype test program.