In 1983 Ballard and two younger partners, engineer Paul Howard and electrochemist Keith Prater, changed course, winning a contract from the Canadian military to research a more exotic form of power. Fuel cells had been around for 150 years and were used in the Gemini space program but were thought to be too expensive for any practical use. As Ballard's team began to make the cells lighter, smaller and thus cheaper, it realized that the technology could eventually be used in vehicles.

Skeptics--"pistonheads," Ballard calls them--say the company is decades away from making fuel-cell cars affordable, if it ever can. But some of the largest automakers are betting on a hydrogen future. DaimlerChrysler and Ford have paid $750 million for 35% of Ballard Power Systems, vowing to market fuel-cell cars within five years. Since hydrogen is difficult to store, current research focuses on fueling the cars with methanol, from which hydrogen would be extracted on board. That process would produce pollution, but not nearly as much as conventional engines give off.

In late 1997 Ballard, now a multimillionaire, retired as chairman of his company, but he's confident that his successors can fulfill his vision. He has already turned many doubters into believers. Science colleagues who were once "embarrassed to be seen with me at professional symposia," he says, now call upon him to give speeches. "Be impatient," he counseled students at British Columbia's University of Victoria as he accepted an honorary degree last year. "Challenge the normal. Dare to be in a hurry to change things for the better."