Current mood:

impressed

Department of, "I wish I'd thought of that."
One of the ideas floating around for how to displace our need for oil with a renewable replacement is oil-rich algaes. You take some unused land -- maybe vacant lots that are already messed up from past industrial use -- and set up ponds, and set your little biological friends loose turning CO2 and sunlight into useful hydrocarbons. When you burn the fuel, you're just returning the same CO2 to the atmosphere -- there's no net increase. (And in fact, if you take the non-oil mass and find uses that keep carbon out of the atmosphere on a long-term basis, you may be producing a net reduction in GHGs.)

One of the big problems with this technology is that there's a tradeoff between how densely you let the algae grow before you harvest it, and how deep you can make your pond. If it gets too dense, it blocks out sunlight, preventing layers below from growing. So there's a pretty firm cap on how much can be grown per unit area.

Enter Bionavitas Inc. The founders of Bionavitas asked what is, in retrospect, a kind of obvious question. Does light really have to filter down through the water from the surface? They basically set up tubes* that pipe sunlight in, kind of like these popular tubular skylights. As a result, they can now grow algae in meter-deep ponds, while achieving the kind of density you normally only get in the top few inches.

This is seriously one of those, "Well, duh!" ideas. And I hope they get very, very rich off of it, since that would mean a lot of nice algae-based biodiesel coming onto the market. (Incidentally, a Presidio team that graduated last semester has been working on an algae plan involving using algaculture to remediate land damaged by mining. They say they'll be able to restore land to a state where once they drain their ponds, you can let regular ecosystem succession take place -- meadow, to scrub, to forest -- and during the process, they produce a salable product. Not bad, if they can really pull it off.)

* Their algae farming technology is a series of tubes. It's not a dump truck.