"I think there are some real possibilities here--significantly improving the efficiency of the automobile and being able to price the car at something close to competitive," said Lee, who is also a lecturer in public policy at the Kennedy School.

Fueling Up

But the low pollution levels of fuel cells, while seemingly their raison d'etre, is also their most damning flaw. A fuel cell is a highly efficient reactor, but is notoriously picky about what it consumes--only pure hydrogen and oxygen gas.

Oxygen is readily available in the atmosphere. But hydrogen only exists in trace amounts in the air, and must be produced artificially--usually from fossil fuels, and perhaps in the future from rotting biomass and solar panels.

But while a multi-trillion dollar global industry has evolved to refine and distribute gasoline, no such infrastructure is in place for producing hydrogen gas.

"In today's society, you can't run over to the corner gasoline station and fill up on hydrogen," said William L. Mitchell, senior program manager for the Hydrogen Technologies Unit of Arthur D. Little--a Cambridge based technology consulting firm.

"Gasoline is the only thing out there that people are comfortable buying for their cars," Mitchell said. "If you're asking one of the Big Three auto makers to bet a billion dollars on making a car that doesn't have a fuel, that's a hard thing for them to do."

While alternatives have been proposed, some companies have tried to find a middle ground by using methanol instead of hydrogen gas.

For example, Daimler plans to use methanol in its fuel cell cars and extract the hydrogen on-board. But experts have said that it will also be difficult to supply methanol to customers.

The Ideal Solution

Because of the distribution problems associated with any exotic fuel, companies have struggled for many years to figure out a way to extract hydrogen directly from gasoline.

Chemical refineries routinely break down fossil fuels into hydrogen gas and carbon dioxide. But, until recently, there was no way to carry out this reaction in a box small enough to fit under the hood.

For the past five years, a team of 48 engineers and market strategists at Arthur D. Little has been working with the Department of Energy and the Chrysler Corporation to develop a high-tech gadget called a "reformer" that would solve that problem.

This October, they succeeded.

"We were able to reduce the reformer to the size for an automobile, and we got it so that it can power a mid-sized vehicle," said Bob Derby, head of marketing for Arthur D. Little.