Environmental Impact of Algal Biofuels

Last semester I worked on a feasibility study for a company started by a UT professor which is looking to commercialize algal farming for use as a feedstock in biofuels.  Algal biofuel is not a new concept and in fact there has already been a significant amount of investment in this area of energy research by both the public and private sectors.  Since I am a business student my work on the feasibility project focused on the business case and cost perspectives rather than the engineering and biology involved.  Though I am not an engineer and do not have a thorough understanding of all the biological and engineering processes going on, I did developed a reasonably good understanding of how we can utilize algae and the potential benefits from this form of energy.  

So, the question is what exactly am I writing about?  I was sent an article by a former team member about a paper, recently published (1/19/10) in the journal Environmental Science & Technology, in which researchers from the University of Virginia’s Department of Civil and Environmental Engineering claim that algae used for energy has a higher environmental footprint than other recent (conventional) biofuel production methods such as switchgrass, canola, and corn farming.  Their claim is that “these conventional crops have lower environmental impacts than algae in energy use, greenhouse gas emissions, and water regardless of cultivation location.”  The report suggests that “The large environmental footprint of algae cultivation is driven predominantly by upstream impacts, such as the demand for CO2 and fertilizer.”  Additionally the report mentions that “To reduce these impacts, flue gas and, to a greater extent, wastewater could be used to offset most of the environmental burdens associated with algae.”  

The two key arguments available in the abstract of the research paper regarding water and CO2 emissions were negated by the researchers when it was suggested that waste water and flue gas be incorporated into the process.  This is the same assumption industry has been working with for sometime in the effort to commercialize this technology.  Again, I must mention that I am not an engineer and the UVa researchers have more knowledge on this topic than I do.  That said, I still question how accurate the conclusion is that algae based fuel are not as environmentally friendly as traditional bio fuels based on what I learned from working on a algae biofuels project. 

The project I worked on last semester assumed water used for the algal ponds was either treated municipal waste water or water from nearby streams or lakes.  Both of these types of water would provide nutrients for the algae to grow.  Lake or river water would be cycled through the ponds as necessary and released back just as clean as or cleaner than when it was used in the ponds.  This is a key assumption in the algae as a fuel source argument because it shows that no fresh water is soiled in the algal growth process.  So while algal ponds do require an enormous amount of water, they do not diminish available water for our consumption. 

Another key assumption we made was that the algal farms would be placed near a coal burning power plant were we could utilize the post scrubber emissions to feed CO2 to our algae.  This not only provided food and temperature regulation for the algae, but also is a form of temporary carbon sequestration.  The benefit here is that the carbon released from the power plant does not just go into the air, but is transferred to the algae which use it to grow.  Though the CO2 will eventually be released when the algal oil is burned, the net effect is less than the amount released if the coal plant emitted CO2 directly into the atmosphere and crude oil was used as a transportation fuel rather than the algal oil. 

Algae, because it can be grown in ponds does not need fertile soil like traditional crops so it does not compete with food crop for land.  This is a major advantage over ethanol.  More specifically algae can be grown on undesirable land around a power plant which is generally bare and undeveloped. 

Ethanol also has logistical problems associated with its transportation.  Ethanol is hygroscopic and cannot be transported through our existing pipeline infrastructure the same was gasoline and oil are; algal based biofuels do not have this restriction.  Furthermore, the process we were working with assumed that the type of algal oil our process yielded could be directly mixed and refined with traditional crude oil allowing it to utilize a transportation and refining infrastructure already in place.

Algal oil is not an easy solution to our energy addiction, and it will likely never fully replace traditional crude oil.  Algal oil is however a game changer and can help diversify of our energy portfolio.  Algae based bio fuels have the potential to help reduce our dependence on oil as the primary transportation fuel, while also reducing the environmental strain caused by our current energy use.








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4 responses to “Environmental Impact of Algal Biofuels

  1. Rachel Denton

    Although you gave great examples to show the ways in which algal biofuels are environmentally friendly, those examples were all based on assumptions used for the purpose of your work, that unfortunately, are only assumptions, and do not reflect as a whole the normal standards for algal biofuel production.
    At this point in time, algal biofuels are less environmentally friendly than say corn or switchgrass primarily because they emit more green house gases, use more water, and consume more energy than alternative biofuels do.
    Many suggestions have been made to improve these problems, and many of them incorporate the very assumptions you mentioned in your post, but they are just not in place currently.

    For example, a great way to reduce CO2 emissions associated with algal biofuels would be to use CO2 from coal-fired power plants (which you mentioned), however, at this time that option is not cost-effective, and thus the CO2 used mostly comes from petroleum-based sources.
    Furthermore, algae grows in ponds, which lack the nitrogen and phosphorus needed for the algae to grow, and thus fertilizers (which come from petroleum feedstocks) are used to provide these necessary ingredients. Your point regarding the growth of algae in treated wastewater does not take away from water needed for human consumption, however, I don’t believe that treated wastewater will contain the nutrients needed for the algae, (please correct me if I am wrong), and thus the fertilizer will still be needed.

    In a nutshell, I do agree with you that algal biofuels can help to diversify our energy portfolio and can be quite environmentally friendly, I just wanted to mention that the assumptions you made for your work need to no longer be merely assumptions and become an everyday reality to ensure the success of algal biofuels according to environmental standards.

    Thank you for your post. I really enjoyed reading it.


  2. jgerencser

    I agree with your post that algae can potentially play a significant role in the future of transportation fuel. I also agree with you about questioning the accuracy of the article you described claiming that conventional crops have a lower environmental impact than algae. The article makes this claim, but it does not say how they are comparing the conventional crops to algae. If they are taking a piece of land and comparing them, it does not make any sense because algae is able to produce much more biofuel per acre. Researchers predict algae can produce 10,000 gallons of biofuel an acre annually, while corn can only produce 18 gallons. If the researchers measure the environmental impact of corn and algae when each produced 10,000 gallons of biofuel, their results may change drastically because corn would require over 550 times the amount of land than algae.


    • And don’t forget that conventional crops cannot be paired to carbon emissions directly as a large scale algaculture operation can. Algae has the advantage of a wide range of species to fit any water quality, nutrient source and chemical composition, thus allowing algae to be tailored to the specifics of the carbon emissions and input. I think that is where the real advantages of algae lie.

  3. Bimal, I had the same thoughts when I read about that paper. Producing fertilizer is very energy-intensive, but you’re right, pairing up bioreactors with wastewater effluent or other sources (e.g., fish farms) would reduce the need for nutrients.

    I’m guessing that these are their initial results and they’ll publish on the life0-cycle impacts using water sources with nutrients. With that said, the nutrient question is important and shouldn’t be overlooked.

    I’m glad you posted about this topic, because we’ll talk about it in a few weeks in the algae lecture 🙂

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