In the parking lot of a building squeezed between Interstate 80 and the Sacramento River, Kota Manabe did something at once elemental and revolutionary: He topped off the tank of a sport utility vehicle. The only suggestions that anything was out of the ordinary were the flame-retardant suit the Toyota engineer wore and the fuel he pumped into the Highlander: pure hydrogen. "Basically, it's just like refueling at a normal station,' fellow engineer Kyo Hattori said. Almost. While hydrogen is the most-abundant element in the universe, as an automotive fuel it's about as commonplace as moon travel. There are only...