NEW YORK—The Ferraris, Lamborghinis, Porsches and other conventional sports cars were bumped from the showroom of the Manhattan Classic Car Club today in favor of a motley array of alternative vehicles—many of which could likely out-accelerate the world-renowned sports cars. From high-schoolers modifying a Ford Focus hybrid to run on biofuel to would-be manufacturers of three-wheeled electric vehicles, the X PRIZE's seven automotive expert judges have winnowed a field of 135 vehicles down to 53, powered by six different fuel sources and coming from 18 states and 10 countries. And five of them were on display today in lower Manhattan.

"Forty-three teams have made this cut in the difficult design judging stage," said Peter Diamandis, founder and chairman of the X PRIZE Foundation, at today's event announcing the "thoroughly vetted" winners. "The point is you don't have to choose between beautiful, safe, affordable" or something that "oh by the way, gets 100 miles per gallon of fuel equivalent."

The entrants—who ultimately must build a vehicle that gets the equivalent of 100 miles per gallon of gasoline and that could be mass-produced—were judged on both their technical specifications and their business plans, according to Eric Cahill, foundation senior director. "We're revisiting a century ago, all over again," he says, referring to the time before gasoline became the fuel of choice and alternative fuel vehicles—from electric to biofuel—abounded. "We're in a competition globally, you could say, trying to keep these jobs in the U.S."

The event featured five of the surviving designs, from both the "mainstream" and "alternative" tiers of the contest: a modified Ford Focus hybrid from the West Philly Hybrid EVX high school team; the OptaMotive Surge three-wheeled electric car with a motorcycle engine; ZAP!'s three-wheeled electric Alias; the two-seater Tango electric car, intended for commuters; and AMP's (Advanced Mechanical Products) retrofitted Saturn Sky electric sports car. "We cheated," says AMP co-founder and software chief Mick Kowitz. "We have a road-ready vehicle out of the box."

Of course, the decision by General Motors to shut down Saturn will have an impact on AMP's chances, although the company can retrofit used Sky's equally well. AMP simply swaps out the engine, drivetrain and gas tank of the existing vehicle and plops in their electric version, which relies on repurposed Chinese lithium phosphate batteries to deliver 33 kilowatt-hours of electricity. It costs $25,000 for the retrofit. "We can go 100 miles on one charge," Kowitz says.

And therein lies the challenge of the X PRIZE: With six different power sources—including 22 battery-powered electric vehicles, two cars running on biodiesel, one car running on compressed natural gas, two running on conventional diesel, six capable of burning 85 percent ethanol, and 16 improving the efficiency of burning conventional gasoline—how do you compare efficiency?

The contest's "happy medium" of a solution, according to Cahill, is so-called miles-per-gallon equivalent. In essence, the judges convert any fuel source to its British thermal unit (Btu) equivalent and then assess that against how far the vehicle traveled versus how much fuel it consumed. The equation is miles driven divided by the product of the total energy of all fuels consumed (in Btus) divided by the (energy of one gallon of gasoline in Btus). And to negate some of the advantage this approach automatically gives to electric cars (whose greenhouse emissions include those generated by electric utilities), the award also incorporates other measures in its criteria, including a cap on greenhouse gas emissions of no more than 200 grams per mile. "We don't profess for that to be perfect or ideal," Cahill adds. But it attempts to be as "close to [an] apples-to-apples comparison as possible."

Outside of Progressive Insurance's sponsorship of the prize—for which it has promised the overall $10-million purse as well as operating costs—the mainstream of the American auto industry has not opted in to the contest, despite a multiplicity of announcements ranging from GM's Volt to the battery-electric Ford Focus. But the goal of the X PRIZE, according to Diamandis and Cahill, is to spur innovation—and it may already be having an effect on the existing automakers, weakened by the current recession and changing consumer preferences. "We may not have them in the competition, but we have them in the competition, if you know what I mean," Cahill says.

Next up for the remaining contestants in summer 2010 are actual road races—actually more test track demonstrations than NASCAR. Even so, there will be certain head-to-head competitions staged more as time trials, Cahill says. "We're not competing based on driving. We're competing based on technology, and there's nothing standard about it," he adds. "We're not trying to hurt people out there."

To wit, what the X PRIZE Foundation is trying to do is change the future of the automobile. A winner will be announced in September 2010. "We're going to do this, vehicles are going to change," says Glenn Renwick, CEO of Progressive Insurance. "This is about providing consumers with more choice for fuel-efficient vehicles."