Someone noted that since water vapor is a powerful greenhouse gas, fuel-cell cars might increase global warming due to their water vapor emissions. But the natural evaporation from lakes and rivers in the U.S. produces about 1000 times more water vapor than would come from a transportation system that was totally powered by fuel cells. So the increased moisture in the air is pretty much inconsequential. In fact, fuel cells are about as close to ideal as we can devise in a power system.

The biggest challenge of fuel cells is that they like to run on pure hydrogen, which is difficult to carry on board a car. And there’s no hydrogen delivery infrastructure in place. But these problems are quickly being solved, and production fuel cell cars are just around the corner.

To show you how fast this technology is coming along, I attended the World Car Conference in Riverside CA in 1996. And at the time, there was concern that fuel cells could be cut from PNGV because they couldn’t be ready for production by the 2004 deadline. Well that was only about 4 years ago, and if you go out to Palm Springs today, you’ll see production fuel cell golf cars running around. And they’ll be showing up in passenger cars pretty soon.