Since President George W. Bush fueled a minivan with hydrogen 15 years ago, the promise of cars and trucks powered by the fuel has come up mostly empty.
That hydrogen pump, in Washington, closed long ago. But in California, the beginnings of a hydrogen economy may finally be dawning after many fits and starts.
Dozens of hydrogen buses are lumbering down city streets, while more and larger fueling stations are appearing from San Diego to San Francisco, financed by the state and federal governments.
