You could drink the exhaust of the Honda FCX Clarity. The four-door sedan—the first hydrogen fuel-cell car available to the general public—emits only water. Powered by the electricity generated when hydrogen and oxygen combine to form H2O and with upholstery fabric made of fermented corn, the Clarity sure sounds green. But is it the “zero-emission sedan of the future,” as Honda claims?
Not yet. Most hydrogen fuel is derived from natural gas in a process that releases plenty of carbon dioxide, so the car and its 134-horsepower electric motor fall short of being footprint-free. Still, fueling a vehicle like the Clarity emits less than half the CO2 released by its gas-guzzling counterparts for a given distance, says John Turner of the National Renewable Energy Laboratory in Golden, Colorado. The Clarity’s fuel efficiency equivalent of 68 miles per gallon clobbers even the feel-good 48 mpg of the Toyota Prius, and the car can go 270 miles on a $20 tank.
Just don’t plan on taking it cross-country anytime soon. Honda begins leasing the Clarity this summer ($600 a month, with limited availability) in Santa Monica, Irvine, and Torrance, three Southern California communities with rare access to hydrogen fueling stations. The company is working toward a greener, more abundant hydrogen supply line; a research station at its R&D headquarters turns water into fuel using solar power. The downside? It refuels only one Clarity a day.