Bikes & Cars...

Hydogen fuel cells have been touted as the fuel of the future. In the plus column, it's not petroleum, and the tailpipe emissions come out as everybody's friend H2O, or water. In the minus column, the technology is new and relatively untested, and the infrastructure is sparse: L.A., D.C., and New York are the only metro areas with hydrogen filling stations. So where does that leave the rest of us?

Though momentum is gathering behind plug-in electric vehicles and straight electric cars, manufacturers aren't putting all their eggs in one EV basket. At last week's lunch in Seattle, GM bigwig Bob Lutz opened his remarks by reminding us of Project Driveway, which has put over 100 hydrogen-powered Chevy Equinox SUVs in the hands of drivers. 

Honda has released a small fleet of its FCX Clarity hydrogen-powered cars to consumers in Southern California this summer. This car looks Civic-like, but it only comes in one color (thankfully, not green. That would be too obvious). Like the GM EV-1, star of the documentary "Who Killed the Electric Car," the Clarity can only be leased, for $600 a month. Basically, Clarity drivers are paying for the privilege of performing Honda's long-term testing.

BMW has the Hydrogen 7, its "luxury performance sedan" powered by fuel cells. This car isn't yet on the market, but the company has made 20 of them available as loaners to movers and shakers like Jay Leno, Edward Norton, Jason Bateman, Will Ferrell, Joely Fischer, and Brad Pitt. I'm not holding my breath for my turn; I recommend you don't, either.

A quick primer on what makes these cars go: The hydrogen circulates through a cell that splits it into positive ions and negative electrons. The electrons create an electrical current that powers the motor. The hydrogen ions combine with oxygen from the air to form water, which is channeled out of the fuel cell. It's probably not potable, but it's way better than what comes out of your tailpipe now.