In 2003 President George W. Bush announced a billion-dollar plan to help usher in a new era of zero-emission, fossil-fuel-free driving. One of the more popular solutions to the looming crises of rising oil prices and climate change at that time was the hydrogen fuel-cell vehicle. These cars would be run on compressed hydrogen gas, which would be converted by a series of onboard fuel cells into electricity to power electric motors. Instead of releasing harmful greenhouse gases into the air, the byproduct of this process is water (hot water, to be specific), an almost comical puff of steam.

As soon as the money was available, the U.S. Department of Energy began doling out grants to universities, federal funds flowed into the research and development labs at the Detroit Three, and energy firms lined up for millions in subsidies to create newer, cleaner methods of squeezing hydrogen from coal and other existing energy sources.

Five years later, at the 2008 Los Angeles Auto Show, only one new hydrogen vehicle was unveiled — Honda\’s FC sport car concept, running on the same fuel-cell stack used by the company\’s existing FCX Clarity sedan. Meanwhile, a slew of new all-electric and hybrid-electric cars were on display, including an electric MINI Cooper and hybrid versions of previous models, such as the Ford Fusion. The electric vehicle, along with its less-ambitious hybrid electric-gas-powered cousin, has all but stolen hydrogen\’s thunder. So what happened?

Lack of Infrastructure

Just last year, the Department of Energy began funding the development of plug-in hybrids. And despite billions in federal dollars, the only hydrogen car produced in significant numbers by a U.S. automaker is the Chevrolet Equinox Fuel Cell, which was distributed earlier this year to approximately 100 drivers in California, New York City and Washington, D.C., as part of a test program. The only commercially available new fuel-cell car on the road today is Honda\’s FCX Clarity, which is being leased to around 200 customers in Southern California. The catch: Applicants must live near one of three 24-hour hydrogen filling stations and be willing to pay for a 3-year, $600-per-month lease — roughly the same cost as leasing a new Porsche Cayman sports car or Mercedes-Benz E350 luxury sedan. The bigger catch: There are just 65 hydrogen refueling stations across the country, and little hope of major expansion in the near future.

\”The technology is here; the car is ready,\” says Todd Mittleman, a spokesman for Honda. \”Now, the infrastructure has to grow.\”

Compared with the more ambiguous goal of upgrading the country\’s electric grids to handle more hybrids or electric vehicles, the prospect of building a comprehensive network of hydrogen fueling pumps is daunting, to say the least. Hydrogen pipelines exist, but they tend to be relatively short, connecting oil refineries (the primary customer for hydrogen) with production plants that are either on-site or located nearby. And since the hydrogen is transported as compressed gas, existing oil and gas lines would have to be replaced, rather than retrofitted. In the short term, hydrogen could be shipped in trucks, which would raise the overall cost and carbon impact of the fuel.

Another hurdle — if the energy used to process the hydrogen comes from coal-fired plants or other emissions-producing sources, how do you build a hydrogen economy without an increase in airborne pollutants? After all, the clean-coal technology that many had hoped would clear the way for a hydrogen-powered future is still little more than a campaign promise (both John McCain and Barack Obama pledged to fund carbon-capture research).

Lack of Raw Materials

More bad news for hydrogen: the high price and potential scarcity of platinum, which is used as a catalyst in polymer electrolyte membrane (PEM) fuel cells. There are many different kinds of fuel cells, but with their relatively low operating temperatures (roughly 200 degrees Fahrenheit), PEM cells are the most compatible with vehicles.

Honda\’s Clarity, arguably the most efficient hydrogen vehicle on the road, uses a vertical stack of PEM cells. Hydrogen and oxygen flow into the cells, where a catalyst helps convert hydrogen ions into electricity. Currently, the best catalyst appears to be a thin coating of platinum. Honda President Takeo Fukui predicted that hydrogen cars could become commercially viable by 2018, if priced similarly to a new luxury car. For the technology to compete on a wider scale, researchers will have to find a new catalyst.

\”There will be a platinum alternative,\” says Fritz Prinz, chairman of Stanford University\’s mechanical engineering department. \”There are metal alternatives, some of which we\’re in the process of patenting now, and nonmetal alternatives. I would expect to see progress over the next five to 10 years.\” Another approach already showing results is platinum alloys, which incorporate less of the rare metal.

Can Hydrogen Become a Reality?

Even so, Prinz believes that, despite all of their inherent challenges, hydrogen cars could become a reality due to raw necessity. \”Hydrogen depends ultimately on what the larger energy infrastructure looks like. If it\’s solar, then storage will be big,\” Prinz says. Solar panels, like wind turbines, are intermittent power sources — their output spikes and plunges depending on the time of day and changing weather conditions.

Without an efficient way to store that energy, and then release it in measured, steady increments to meet the shifting hourly requirements of electric grids, solar-power providers risk either throwing away excess energy during low demand or coming up empty during peak hours.

While some experts believe that battery technology could eventually provide enough efficiency to store and release solar power, Prinz sees hydrogen as a more practical solution. \”Solar can only become effective and feasible once you have a parallel of energy storage.\” The energy produced by photovoltaic panels could be used to extract hydrogen from another renewable resource: water. Strategic placement of solar farms could limit the length and number of hydrogen pipelines. This is a relationship that Honda is already exploring, with a demonstration home in Torrance, Calif., that uses rooftop solar panels to generate hydrogen, with a refueling station located in the garage.

Whether it\’s simply a marriage of convenience, or symbolic of the kind of cooperation many believe is necessary to reduce carbon emissions and dependence on oil, hydrogen\’s best hope for survival might be as the indispensable sidekick of another power source that\’s been stymied by the need for a long-term, large-scale infrastructure commitment. Still, the most optimistic estimates have hydrogen as a viable mainstream choice in a decade. Honda has no immediate plans to expand its pool of Clarity customers, and the FC Sport car it unveiled at the L.A. Auto Show is just a concept. Unless you\’re one of a few hundred early adopters, the hydrogen car is still miles down the road.