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Sequester CO2 by growing algae ?!? 13

You don't sequester carbon by growing algae; you capture carbon dioxide from some enriched source. And then you convert it into biofuel.

It is no different from what any farmer does when he grows a crop and for example makes a biofuel out of that.

The CO2 abatement is strictly based upon the replacement of fossil fuel with biofuel.

It is not based upon actually sucking out the CO2 from a flue gas or some other source. So that is a little bit of a conceptual problem. People think that by capturing CO2 you are doing some benefit. That is not the case.

The benefit can only come on the biofuel side, if you are replacing fossil fuel with a biofuel. And then you have to do the calculations of how much energy went in and what kind of boundary conditions you set on the whole thing, which is the life cycle analysis, or LCA, that many people now are doing.

As you know, there's a controversy in the case of some biofuels, which basically don't really have a significant reduction in CO2 emissions, not a positive LCA.

We believe that algae can have a significant reduction in CO2 emissions compared to burning fossil fuels but, the way I put it, the CO2 capture side is a necessity, not a virtue. In other words, if you want to grow algae you need to feed them CO2 from an enriched source, such as a power plant.

If you grow crops, they get the CO2 from the air. So, we need to feed algae CO2, but that is not a virtue in terms of we cannot make any claims of reducing CO2 emissions just by capturing CO2 from a power plant.

Source JB
Tue June 01 2010 10:47:30 PM by Manohar 2047 views

Comments - 5

  • Erika wrote:
    Tue June 01 2010 11:39:58 PM

    Hi Manohar, I work for an algae-based fertilizer company in N. California, U.S.A. Our community, Humboldt County, has a strange predicament in that we have a 60 million gallon/day surplus of industrial-grade water. We need to find an industry to utilize this water or lose it to S. California. This could be an opportunity to establish an algae farm, either ponds or PBR's. We also have a large, shallow bay for mariculture. A wood-fired power plant is attempting to go online, has been off for 10 years. They currently are facing fines for excess emissions during a trial run recently. With the algae industry going commercial this year and government funding finally pulling through, I feel that what may seem like a pipe dream may be feasible. Seeing as how I know few people with a perspective, I was wondering if you might offer any thoughts. I would love to introduce the concept to the community tonight at a meeting and am gun-shy. Do you think these dreams are feasible?

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  • Narsi wrote:
    Wed June 02 2010 04:17:12 AM

    @ Erika - your post is very interesting...I did some math on that, and here are the results

    Total amount of wastewater = 60 million gal/day = 225 million liters

    Normal yield of algae (dry biomass) in open systems = 1 g/l per day

    Thus, total amount of algae biomass (dry) per day from 225 million liters = 225 T

    @ 30% oil yield by weight, you get about 70 T per day or 25,000 T per year.

    Taking the value of this oil @ $ 600 per T, you can make $ 15 million.

    Now, the above math is of course theoretical and does not in any way prove the technical or economic feasibility, but I'm sure it gives you a business case for further thought.

    Hope this helps, and let me know if you require more inputs on this; I was part of the Oilgae team that has published the comprehensive report on wastewater treatment using algae ( http://www.oilgae.com/ref/report/wastewater_treatment/wastewater_treatment.html ). So, I can ask my team to provide you any specific inputs you might require on this...

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  • Fri June 04 2010 12:48:08 AM

    I am curious to know how Ericas meeting went?

    Vote Up! 2 Vote Down! 0

  • Manohar wrote:
    Sat June 05 2010 05:14:16 AM


    HOw did your meeting go?

    Vote Up! 1 Vote Down! 0

  • Mahesh wrote:
    Sat June 05 2010 06:22:41 AM

    Hummm........ Mere growing of algae itself is a lot of CO2 capturing, because they are 8times more efficient than plants in that carbon capture business... And some contribution by reduction in CO2 emissions of algal based fuels..

    So, double benefits and CO2 capture at two phases...This is my concept and understanding.. How does this sound!!!!!!!

    Vote Up! 4 Vote Down! 0

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