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Where does the Carbon go?
It Came From the Swamp
Reengineering Algae To Fuel The Hydrogen Economy.
The coming hydrogen age promises guilt-free SUVs and factories that belch steam instead of smog. But where will all that hydrogen come from? California startup Melis Energy thinks it has the answer: genetically enhanced pond scum.
Traditional methods of extracting hydrogen from H2O take electricity, which usually means torching fossil fuels. Alternatives exist, but solar cells are pricey, and windmills are limited to windy areas. Industrial hydrogen producers get their supply by blasting natural gas (CH4) with scalding steam, and fuel cells use a similar method to strip hydrogen from gasoline, wood alcohol, or methane. In other words, hydrogen production may be a big improvement over internal combustion, but it still unleashes plenty of greenhouse gases. So what to do?
Use algae, says Tasios Melis. His breakthrough came in 1998 when, as a UC Berkeley biochemist, he was tinkering with green algae, trying to coax the plants to convert water into hydrogen. Algae have long been known to produce minuscule amounts of the gas. Trouble is, the enzyme that propels the reaction (hydrogenase) stalls in the presence of oxygen, and - think back to high school bio - plants naturally produce oxygen during photosynthesis.
Melis found he could reprogram photosynthesis and stifle internal oxygen flow by depriving the plant cells of sulfur. Under these conditions, the algae pumped out hydrogen for days at a time - lots of it. "We thought maybe we'd get a little hydrogen," Melis says. "But it came out in bulk amounts." An acre of his pond scum, he calculates, could produce enough H2 to power a car from Sacramento to Seattle - and theoretically much farther.
Recognizing the commercial possibilities, Melis and his colleagues applied for a patent and published their results in 2000. Last year, he recruited entrepreneur Steve Kurtzer as CEO and engineer James Candy as director of engineering, and Melis Energy was born. The startup's goal: license the technology to power generators, fuel wholesalers, and hydrogen producers. Kurtzer is negotiating with private investors for $10 million to cover R&D. If that comes through, Melis and Kurtzer predict their algae will hit the market in two to five years.
Melis sees widespread applications for his method. "This is low tech," he says. "It won't require fancy equipment or industrial facilities. A farmer could do it." The company is trying to patent a tubular bioreactor - a network of sealed tubes - for cultivating algae and extracting pure hydrogen. Each unit might hold 5,000 to 10,000 gallons. A megaplant could hold as many as 1 million.
At the moment, Melis' method won't cut it in the marketplace. The algae-hydrogen system generates electricity that costs about 31 cents a kilowatt-hour. Natural gas-fired juice runs a nickel or less. But a solution is in sight. Melis' team recently uncovered the key bottleneck in its green biomachine: Hydrogenase is present in only tiny amounts. By genetically engineering algae that express high levels of the enzyme, the team expects to double hydrogen output.
Still, if you thought solar power was fringe, try selling algae to the big boys. Algal fuel is certain to face skepticism and stiff competition. Natural gas isn't going anywhere, and cost-saving advances in solar, wind, and biomass conversion are inevitable. "What Melis has done is the most advanced to date in the biological area," says Seth Dunn, an energy expert at the Worldwatch Institute. "I'd put it in the wild card category." Then again, that's what they said about the horseless carriage.
- Michael Mechanic