In 2015, American consumers will finally be able to purchase fuel cell cars from Toyota and other manufacturers. Although touted as zero-emissions vehicles, most of the cars will run on hydrogen made from natural gas, a fossil fuel that contributes to global warming.

Now, scientists at Stanford Univ. have developed a low-cost, emissions-free device that uses an ordinary AAA battery to produce hydrogen by water electrolysis. The battery sends an electric current through two electrodes that split liquid water into hydrogen and oxygen gas. Unlike other water splitters that use precious-metal catalysts, the electrodes in the Stanford device are made of inexpensive and abundant nickel and iron.

Because hydrogen fuel infrastructure is more or less non-existent, Hyundai's rollout will be small. The car will be available at select dealers in Southern California, all within range of the company's sources of hydrogen, which include a nearby waste water treatment plant. Local drivers will be able to "gas" up for free at any of seven distribution stations...