Pond scum to the rescue

mit_power_plant_algae.gifMysterious organisms, greenhouse gas reduction, a lucrative business opportunity, and a new type of fuel.  All in one package!  What more could you ask?  Well, it’s also green, literally.

This is the new promise of that lowly, misunderstood life form, pond scum. Or, more accurately, algae.

The full story is at Worldchanging. After a long period of experimentation, culture of oil-rich algal strains is beginning to show promise both for reducing carbon emissions and as a biofuel.  In an ingenious model of industrial efficiency, Isaac Berzin at MIT developed an “emissions-to-biofuels” process in which industrial smokestack emissions are routed through an agal culture reactor that scrubs out CO2 and nitrogen and turns them into algal biomass, the natural oils from which which can then be converted to biodiesel.  A win-win situation.  Cool idea, but can it make the transition out of the lab?

The answer appears to be yes.  This technology is now moving into industrial-scale applications.  Greenfuel Technologies is installing the algal-based emissions-to-biofuels technology on power plants in Arizona and South Africa.  Another company, Green Star, struck a deal last November to build 90 algae-based biodiesel reactors, also in South Africa.

Is this the new wave?  It appears that the brief euphoric honeymoon for crop-based biofuels is coming to an end.  Even the mainstream news media now get this — as evidenced by U.S. News and World Report’s cover story last week.  Corn production for ethanol is water- and energy-intensive, competes for precious food-producing land, and is inefficient in that only the corn kernels are converted to fuel, with the rest of the plant tossed out or plowed under.  Cellulose-based ethanol shows more promise (as discussed in a previous post) since it can be made from the whole plant, wood debris, or other sources, and competes less for arable land.  But that technology has a good way to go before becoming commercially feasible.  And, not suprisingly, the devil is the details for all of these options.

As potential biofuel producers, algae have several advantages over garden-variety land plants like corn. A few examples:

(1) In part because they produce virtually no structural tissues like stems and bark, microalgae grow much faster than land plants.  They are lean, green, photosynthetic machines.  It’s been estimated that oil yield from algae is 7-31 times greater on a per-area basis than that of the next most productive crop, oil palm (which, incidentally, is cultivated on land cleared from tropical rain forest and is burning that forest up at an alarming rate).  (2) Because algae need high light but not soil, they can thrive in arid areas where they don’t compete for arable land, such as Isreal and the American southwest.  (3) The algal oils can even be modified into jet fuel.

As a marine biologist who has spent much of my adult life on intimate terms with algae, this is something I can get behind.

(Photo of algal-filled tubes at MIT’s power plant by Ashley Ahearn)

About Emmett Duffy

I am a Natural Patriot and an ecologist with expertise in biodiversity and its importance to human society. My day job is Professor of Marine Science at the College of William and Mary in Virginia.
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5 Responses to Pond scum to the rescue

  1. Neat. I’m a bit skeptical about the economical viability of algae culture for biofuel. It probably takes complex plumbing and engineering to grow the algae, and then of course more processing to turn it to biodiesel. But if it’s simultaneously getting rid of power plant waste then it might be worthwhile.

  2. Emmett Duffy says:

    Fair enough, James. But of course it also takes complex engineering (big diesel-powered combines and other gear) to grow corn ethanol, and even more complex machinery to find and process petroleum (not to mention maintenance and deployment of the military to ensure a stable supply). Algae are certainly not the whole answer, but may be one component of a “silver buckshot” (as opposed to silver bullet) solution. For more than you probably ever wanted to know about this, check out Oilgae

  3. Matt Duffy says:

    Sounds promising. We are still in the infancy of the sustainable energy economy, and some technologies that look great in the lab are bound to fizzle in the wider world. But one of the more pressing challenges we face today is getting utilites to install proper carbon scrubbing systems on power plants. If algae is the key to turning such systems into viable revenue sources, those clever folks at MIT might really be onto something.

  4. Paul Richardson says:

    How exciting! I’ve always had a hunch that the cure for many of our pollution problems would lie with the algae. I wonder if they could also incorporate the removal of mercury in this process?

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