Expect to hear plenty more about pond scum in the coming months and years. Oh yes, pond scum. A few airlines have already been fiddling with algae-based biofuels for their planes; and now algae may also offer a way to recycle our carbon emissions. Here's what I'm talking about: As Josie Garthwaite first reported last Friday, there was some curious fine print that got added to the stimulus bill in the waning hours. The bill that Obama signed doles out $1.5 billion for research into new fossil-fuel technologies, including efficiency upgrades and carbon capture. But, at the eleventh hour, this language got tweaked to provide "a small allocation [of funds] for innovative concepts for beneficial CO2 reuse."

Innovative concepts, eh? What's that about? Earlier this week, I spoke with Elizabeth Moeller, a lobbyist for Pillsbury Winthrop who helped negotiate the language. Her firm represents Ternion Bio, a company that claims to have developed a cost-effective algae bioreactor process, whereby carbon-dioxide emissions captured from power plants or industrial sites could be used to grow algae. The algae could then be recycled into biofuel, say. Now, this might prove a green alternative to capturing the carbon and simply stuffing it underground in geological sites, which is often touted as a way to reduce greenhouse-gas emissions from coal-fired plants. After all, it's still unclear if sequestration will even work on a large scale. (Algae bioreactors probably won't work on a large scale to capture all of our coal plant emissions, either, but they might come in handy in smaller situations: say, a site that wants to capture or recycle its CO2 but is located too far from a suitable underground storage site.)

Anyway, the main point, Moeller argued, is that both the Energy Department and Congress have long just funneled carbon-capture funds toward geological-sequestration projects, without even considering other possibilities. So that's where the new language comes into play. Speaking of which, I asked Moeller if this whole episode might demonstrate some of the hazards in letting Congress, rather than the market, pick and choose which technologies to fund; she replied that though they had initially sought a provision to fund algae recycling specifically, they settled on this "innovative concepts" language so that the Energy Department could consider a whole range of proposals that are just starting to emerge. Like solar reactors, say.

--Bradford Plumer