In The Field

AAAS 2010: Energy that’s really green

Before too much longer, according to the participants in one of the AAAS press conferences this morning, we could be topping off our fuel tanks with processed pond scum, also known as algae. An algae-based biofuels industry would make the trade-off with food go away: algae will happily grow in ponds built out in the desert, or in other sites not useful for farming. It will thrive in waste water from sewage treatment plants and the like. It will eat up carbon dioxide from power plants, assuming that you bubble the exhaust through the algae pond on the way out. And every one of the intensely green algae cells is bulging with rich, oily lipids that are virtually gas-tank ready. Oh, and the residual solids are useful as fertilizer, or even as food additives.

But as usual with fossil-fuel alternatives, said the panelists, the trick is to get the price down into the competitive range. Until recently, the cost of algal fuel was estimated at $10 to $40 per US gallon, which was too high by a factor of 10. But Bob Hebner, director of the Center for Electromechanics at the University of Texas in Austin, said that by paying careful attention to the full algal fuel life cycle — selecting the right algae strain, growing it, harvesting it and then breaking up the cells to extract the lipids — his lab has recently been able to come in below $3 per gallon. They aren’t yet sure they can do it consistently, he warns. “We did it in the fall, can we do it in the spring? There are lots of variables,” he says. But he’s very optimistic.

Now all that’s needed is a few tens of millions of dollars in investment, and the construction of a national algal fuel infrastructure capable of industrial-scale production measured in the billions of barrels


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