Dear EarthTalk: Not long ago we were reading a lot about hydrogen's role in a clean energy future, with cars transitioning from gasoline-powered engines to hydrogen-powered fuel cells. Where does hydrogen fit now in the mix with electric cars now coming on so strong? -- Amanda Jenkins, Troy, Mich.

It is true that just a few years ago everyone was talking hydrogen fuel cells as the future of petroleum-free automotive transport. Fuel cell cars can run on infinitely renewable hydrogen gas and emit no harmful tailpipe emissions whatsoever. A 2005 Scientific American article bullishly reported that car company executives "foresee no better option to the hydrogen fuel-cell vehicle in the long run." Likewise, the International Energy Agency suggested, also in 2005, that some 30 percent of the global stock of vehicles -- 700 million cars and trucks -- could be powered by hydrogen fuel cells by 2050.

But high development costs and implementation hurdles have kept fuel cell vehicles out of the mainstream for now. And in the face of competition from a new crop of all-electric and hybrid-electric vehicles lately, some analysts wonder whether the fuel cell's future is as bright as once thought.

The lack of widespread demand precludes cost-saving mass production. Also, the lack of hydrogen refueling stations around the country limits the practicality of driving a fuel cell vehicle.

But FCVs aren't dead in the water yet. A few dozen Californians are already driving one of Honda's FCX Clarity fuel cell cars. A $600/month lease payment entitles qualifying drivers to collision coverage, maintenance, roadside assistance and hydrogen fuel, available via a handful of "fast-fill" hydrogen refueling stations.

Contacts: IEA, www.iea.org; Honda FCX Clarity, www.automobiles.honda.com/fcx-clarity.

EarthTalk is written by Roddy Scheer and Doug Moss of E -- The Environmental Magazine. Send questions to: earthtalk@emagazine.com

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