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Power from pondscum: Algal biofuels

The views expressed are those of the author and are not necessarily those of Scientific American.


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In the discussion of alternative energy and fuels, algae have been bubbling to the top of the proverbial feedstock pool. Algae, the little green guys responsible for everything from making your Dairy Queen Blizzard solid to forming the basis of our current fossil fuels, are being looked at long and hard by some of the nation’s top researchers and decision-makers as a source for next-generation biofuels.

Biofuels are already produced in large quantities. In the United States, corn is used to produce tens of millions of gallons of the ethanol each year. Biodiesel, produced in smaller volumes, can be produced from everything from waste cooking oil to soybeans and tropical plants.

Unfortunately, corn ethanol and terrestrial plant-based biodiesel face significant environmental and social dilemmas. Reliance on food crops for fuel poses problems for populations around the world that rely on basic staple foods such as corn. Deforestation is rampant in tropical climates as forests are cut down to accommodate oil crop production. And all of these crops require vast amounts of land and water.

Enter algae.

The idea is that algae can avoid some of the problems facing our current sources of biofuels. As evidenced by algae growing in backyard pools around the nation, algae aren’t the pickiest organisms; algae primarily require sunlight, carbon dioxide and water to grow. Carbon dioxide can come from power plants and industrial emitters, which not only results in faster growth, but also would let carbon dioxide from fossil fuels be recycled before being emitted to the atmosphere. Unlike terrestrial crops (like corn), algae can utilize wastewater for growth, reducing demand on scarce water resources.

And most important, algae produce useful compounds that can be formed into fuels and chemicals desperately needed by our society. Synthetic gasoline and diesel, jet fuel, ethanol and biodiesel can all be produced from different parts of the algal biomass and lipids, while some algae strains have been shown to produce hydrogen.

Although algae are appealing, it will be awhile before we’ll be filling up our tanks with algae-based fuel: A recent article published in Science details the research needed to advance algal biofuel production. In short, researchers and engineers need to know more about every stage of the process, from what alga species to grow to the exact growth conditions and production processes.

The state of algal biofuel science is maturing quickly but is still very much in the early stages. Algal biofuel production is very similar to the beginnings of modern agriculture years ago. If you asked a farmer today to plant a crop, he would know exactly what seeds to sow, crop rotations and nutrient requirements. Ask someone to grow algae for biofuels today, and you’ll get as many answers as there are alga species.

The future is bright, though. With advances in research, our energy future might be bright green.

References:

Pienkos, P. (2009). The Promise and Challenges of Microalgal-Derived Biofuels. Biofuels and Bioproducts 3 (4). doi: 10.1002/bbb.159

Schenk, P. (2008). Second Generation Biofuels: High-Efficiency Microalgae for Biodiesel Production. Bioenergy Research 1:20-43. doi: 10.1007/s12155-008-9008-8

Image: www.algomed.de

About The Author: David Wogan is a dual-degree graduate student at The University of Texas at Austin in Mechanical Engineering and Public Affairs. David’s work includes the integration of engineering, biological, and policy disciplines to assess advanced biofuel production in Texas. David received his B.S. in Mechanical Engineering from UT Austin in December 2006. David has worked at National Instruments and at the White House Council on Environmental Quality on the Energy & Climate Change Team. David is a currently a graduate researcher with the Webber Energy Group and writes at The Daily Wogan, his energy and sustainability blog.

 

The views expressed are those of the author and are not necessarily those of Scientific American.

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Comments 8 Comments

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  1. 1. kvsieg 1:45 pm 11/24/2010

    Great, informative article! If algae biofuel production is going to be successful in the United States, do you think there are lessons to be learned from the sugarcane ethanol program in Brazil?

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  2. 2. Eclipse 9:17 pm 11/25/2010

    I just keep hearing about the promise of algae and nothing happens. Each year there is some new breakthrough, some new species that is THE answer, and then a new article comes out that basically implies we are back at the beginning again. How man of these articles are researchers after funding?

    I’ll believe it when I see it. Until then, I’m going to stick with the ONLY real solutions to peak oil and global warming being GenIII and soon to be commercialised GenIV reactors burning nuclear waste and warheads, electric cars, intercity fast-rail and inner city trolley buses,and finally, New Urbanism.

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  3. 3. Melissa Lott 5:17 pm 11/28/2010

    Thanks for the post, David. Appreciate how you mention the "significant environmental and social dilemmas" associated with biofuels (and energy in general). Science and society intersecting, in the energy world… good stuff.

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  4. 4. davidwogan 5:14 pm 12/4/2010

    @kvsieg Thanks! The success of Brazil’s ethanol industry is very interesting and has turned into a successful endeavor in the 500 years since sugarcane was first introduced to the country. Brazil has natural advantages (e.g., tropical climate, rainfall, etc.) that allow sugarcane to grow in large quantities. The Brazilian sugarcane industry also makes use of byproducts rather well (left over biomass is either burned to run the refineries or returned to the soil), something that our industries should consider.

    @Eclipse Thanks for commenting. One benefit of liquid fuels (whether they are from corn, petroleum, or algae) is the high energy density (energy/unit of volume). Batteries and other storage devices do not compare well with liquid biofuels in terms of energy density. Think of the energy needed by an airplane. However I agree that we need an all-of-the-above approach to reducing greenhouse gas emissions.

    @Melissa Lott: Thanks. There are always trade-offs in energy technologies and policies :)

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  5. 5. Ronny 3:46 am 01/4/2011

    I have been doing countless hours of research on the subject because it interest me. I would like to give my opinion on the cost of producing fuel from algae, (this is not to include the price of the facility). From what I have read, there is a company that claims they can produce up to 100,000 gallons of bio-diesel fuel per acre per year, through a closed loop vertical system (the way it was explained it increases the surface area exposed to sun light est.). Assuming that statement is true, then I really don’t see the cost being so high.
    The way I see it, it’s like this, first of all you grow the algae, then the oil is extracted by whatever means. What you have then is unprocessed algae oil, and a dry substance which, I believe is cellulose and starches. At this point you refine the oil into bio-diesel and glycerin . The glycerin being a by product, from what I have read, has about 1700 uses, and could be sold. Now you have two useful products, bio-diesel, and glycerin.
    At this point I would like to get back to the by product of the dried oil extracted algae. Lets start with the starches, they could be fermented to produce alcohol, that could be used for a gasoline replacement then again another useful product. So what’s left over cellulose this could be burned for heat to be used in the processing of bio-fuel, it could be used to create methanol (destructive distillation of cellulose) and/or could be used in the transesertification process to create the bio-diesel. The ashes from the burnt algae could be used to produce lye (sodium hydroxide) also used in the bio-diesel process, also this product could also be used to sequester carbon dioxide (lithium hydroxide, carbon dioxide scrubber).
    With all this being said it seems to me that you wouldn’t have the need to use any external power, because a percentage of the fuel being produced could be used to power you plant operations via a generator. Again from what I have read a 20kw diesel generator @ full load uses about 1.6 gallons of fuel per hour that equates to 14,000 gallons a year. From what I have seen what they were saying about the pumps est…. the power usage for a one acre, and this is a (high conservative) guess would be between 5000-10,000 watts. I just seems to me that everyone only focuses on one product for the algae.

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  6. 6. JDahiya 12:52 am 01/14/2011

    Ronny, excellent point, well made.

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  7. 7. Ronny 1:20 am 01/14/2011

    I just need to add a little bit to this, and make a correction. The addition is that the exhaust gasses from burning the algae could be fed to the algae (for carbon dioxide), as well as the exhaust from the generator. the correction is Potassium hydroxide, not sodium hydroxide.

    Link to this
  8. 8. phycotech 4:53 am 10/12/2011

    Algae biomass a very good resource to produce different kind of fuels and biodiesel.

    Link to this

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