In praise of the scum of the earth

Green machine: A new push for pond scum power - tech - 12 July 2010 - New Scientist

New Scientist reports on why making biofuel from algae seems to be a good idea, but also notes the problems. On the one hand:

"Ten million hectares of algae could supply all US transportation fuel," says Greg Mitchell of the Scripps Institution of Oceanography in La Jolla, California. That's less than 3 per cent of the area farmed in the US – and algae can live in seawater in the desert.

On the other hand, the penultimate paragraph takes quite a lot of the gloss off the concept:

And ultimately, production will require suitable climate, land, water, nutrients and CO₂, all at one site. Even using waste land, seawater, sewage and smokestack CO₂, Benemann thinks this will limit the potential for algal biomass to the equivalent of 1 per cent of the CO₂ now being released, or less. "But that's still a gargantuan amount. Let's hope we can do that much."

Hmm. Not exactly going to save the Earth, then; but maybe can make a worthwhile contribution?