Another new road to energy efficiency opened to traffic this week, and one automaker hopes this is just the tip of the iceberg for green machines. If this zero-emissions experiment ever takes hold, we may yet manage to preserve those same icebergs.

I'm not talking about the Toyota (NYSE:TM) Prius, with a million units sold. I'm not even referring to the U.S. arrival of Daimler's (NYSE:DAI) Smart Car, which covers a respectable 41 miles of highway on a gallon of gas. No, it was Honda (NYSE:HMC) that proudly unveiled its latest innovation yesterday: a hydrogen fuel-cell vehicle called the FCX Clarity.

The hydrogen fuel cell is hardly new. It's been around since 1839! The principal challenges to its widespread application in vehicles have related to the fuel itself: the need for an entire fueling infrastructure, the cost of creating and distributing the hydrogen fuel, and the energy (often from natural gas) required to produce the fuel.

Considering that the FCX Clarity is confined to an area of Southern California, where just a handful of hydrogen fuel stations exist, Honda does not appear to have addressed one of the longstanding obstacles. Last year, we similarly saw General Motors (NYSE:GM) launch a test fleet of the Chevrolet Equinox FCV in an area that included just New York City and Washington, D.C. With gasoline now topping $4 a gallon, though, the timing and quality of this release from Honda might just provide the spark to get this technology rolling.

As automakers vie for the most attractive fuel-efficiency offerings, another race is on to determine which fuel will burn into the future. Although interest in corn-based ethanol is waning, some promising fuels lie ahead -- for existing vehicles. BP (NYSE:BP) is developing biodiesel made from the jatropha plant, while DuPont (NYSE:DD) recently announced a big push toward cellulosic ethanol. For hydrogen to beat out these alternative fuels, fuel-cell vehicles must offer attractive performance and pricing, and the infrastructure of filling stations will have to fill out quite quickly.

Luckily for Honda, the FCX Clarity is an engineering achievement that may start to lure some consumer interest. With a range of 280 miles, efficiency equivalent to 74 mpg of gasoline, and favorable reviews, the Clarity is undoubtedly clever. Between this 200-vehicle test fleet and upcoming hybrid versions of the Civic, CR-Z, and Fit, Honda is gunning for pole position in the race for cleaner cars.

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