I was recently at an energy forum where a young audience member asked when he'd see hydrogen cars on the road for individual use. A fair question, since we hear about the possibility in the media, and theoretically, this appears to be a good idea.
Compared other fuels, liquid hydrogen has superior energy density at 120 MJ/ kg. Further, fuel cells are able to produce electricity with high efficiency, little noise, no moving parts, and can be designed at different scales. And during the Bush administration, hydrogen got a great deal of of attention as the former president spoke about how its combustion yields water and avoids emissions. Bush II liked the prospect so much that he committed over $1 billion to develop the hydrogen car.
Unfortunately, it's not quite that simple. Yes, the technology is available. In 2006, a lobbyist drove me around the Hill in such a vehicle. Still, hydrogen is not likely to become a significant source of energy for personal cars.
I'm not trying to rain on anyone's parade, but there are some very real hurdles. Foremost, this fuel source requires energy for production. It's also not available in enormous reservoirs in the Earth’s crust. As technologies improve, costs should decrease as vehicles become more reliable, however, distribution issues will remain problematic. Because liquid hydrogen must be maintained below -241 C, storage poses a serious challenge. And then there's the inherent chicken and egg problem: Which comes first, cars or fueling stations? Add the highly flammable factor--Hydrogen has an ignition energy 1/10 of gasoline--and safety should be a concern as well.
So sure, hydrogen has some appeal and may make sense for fleets requiring fewer filling stations. But don't expect to see individual vehicles hitting the highways anytime soon.
