Weighing in at almost 2,600 kilograms, the brawny vehicle at DaimlerChrysler's suburban Detroit skunk works seems an unlikely "car of the future." The lines are distinctly late 20th century. Jump into the driver's seat and it feels like your standard sport utility vehicle (SUV). But pop the hood, and it instantly becomes clear that this is no ordinary gas-guzzler: In place of a combustion engine lies a sophisticated onboard refinery-a fuel processor system of high-pressure gas lines, compressors and chemical reactors to turn methanol into hydrogen gas.

This multimillion-dollar moving laboratory-the Jeep Commander II-feeds the hydrogen to two fuel cell stacks, which silently combine hydrogen and oxygen in a chemical reaction that generates enough electricity to hurtle the SUV down the highway. The car's operation is clean and efficient, generating only water, carbon dioxide and some spare heat. Missing are the toxic air pollutants and fine soot that spew from most vehicles' tailpipes.