Jun 03 2010

Algae Biofuels

Published by under Student blog entries

Photo Courtesy of heatingoil.

Several sources of biofuels exist today, including fuel from soybeans, corn, palm oil, and more recently, algae. Half of an alga’s weight is lipid oil, which is much more than the afore mentioned biofuel sources.1 While the production of biofuels from algae would not reduce the atmospheric CO2 concentration since the CO2 would be returned to the atmosphere when burned, it does not increase the atmospheric CO2 concentration like the traditional fuel sources, petroleum and coal.3 The following is a summary of how biofuel is extracted from algae along with some positives and negatives of this recently conceptualized energy resource.

How it Works: Algae to Fuel

Algae metabolize sugar, by photosynthesis, to make lipid oils, which can be used to make transportation fuels.6 The production process by which algae is used to make fuel involves algae cultivation and harvesting, algal filtration (removing other contaminants) and sometimes drying.5,7 This leaves algal biomass, which then undergoes further processing for oil extraction, and finally chemical conversion to liquid transportation fuel, or biodiesel.5,7 The non-lipid byproducts of this process can be used as feed for livestock, the production of other chemicals, or for biomass burning in coal fired power plants.7,3 This co-firing of coal and algae could increase the efficiency and reduce the CO2 emissions of our traditional coal-fired power plants.3

Pros and Cons of Algae Cultivation Methods

Cultivation can take place in open or closed systems.1,3,8 Open systems, meaning open to the environment and using the sun as the algae’s energy source, run the risk of contamination, such as by invasive species.1,8 Other problems with open ponds include large space requirements and limited potential locations due to climate.8 The water needs to be a certain temperature for algae to flourish enough to be a potential fuel source.1 Several algal fuel production companies propose that closed systems (closed to the environment), or photobioreactors, solve many of these issues.1,3,8 The major drawback to photobioreactors is that they are much more expensive (in both capital and operation costs) than open systems, although these systems are more easily controlled.3,8 Although closed systems have great potential in my opinion, the Department of Energy stated this year that “open ponds are the most viable solution for the mass production of algae for conversion into biofuels.”8

Closed System, Courtesy of KWilsonETS……..Open System, Courtesy of siftnz.

Other Potential Problems

A potential problem that might be foreseen with widespread use of algae as a biofuel is that there could be competition with food crops, as happened with corn ethanol, the corn-based biofuel. One of the many benefits of algae is that it can grow practically anywhere and is less land-intensive than other biofuel sources.1,9 Soy, canola, and palm produce approximately 50, 150, and 650 gallons of oil per acre per year respectively.1 Algae, on the other hand, can produce up to 10,000 gallons per acre per year.1 Algae can also be cultivated in places that are not suitable for agriculture, such as areas with polluted or saline waters.1,2,4,5 With adequate planning, I believe algae biofuel production could have no, or at least minimal, impact on the world’s food market.

Another problem that was posed during my research was that normal atmospheric CO2 concentration isn’t enough to have the high volumes of algal growth needed for adequate fuel production.1 A solution presented by several authors was that CO2 could be harvested from smokestacks, diverted into and bubbled through the algal ponds.3,5

Relevance to Coastal Communities

With the large solar resource in coastal areas and the flat landscape of the NC coast, open system algal ponds could be used very effectively in this area.10

As the main primary producers in the oceans, algae are the base of the ocean ecosystem.3 Large algal blooms are a sign of high nutrient contents in the ocean and are common on the NC coast. These blooms of algae could potentially be harvested and used for biofuel production.10 Farming of algae could also take place in the ocean, although I believe there could be detrimental environmental impacts to the surrounding ecosystem, such as escaping algal blooms, changes to the surrounding trophic structure, and hypoxia.11 Using algae to clean wastewater before it enters coastal waters would reduce such blooms. The Virginia Coastal Energy Research Consortium (VERC) is proposing using algae to clean wastewater and for biofuel, thus reducing the nutrient content of water going into the polluted Chesapeake Bay.10 VERC is also researching “algal milking technology” to extract the oil that that algae leak directly from the water.10

Closing Thoughts

Development and refinement of this energy source is likely to occur in the future. Environmental and economic impacts should be considered before implementation of this source, especially in fragile, highly populated coastal areas.

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4 responses so far




4 Responses to “Algae Biofuels”

  1.   actuckeron 04 Jun 2010 at 7:57 am

    There seems to be a lot of potential for algae biofuels; however, I think there could be vast impacts on the surrounding environment. The environmental impacts should be assessed for each individual project because they would vary greatly with the type of environment it is placed in. I wonder how extensive the process is on collecting the algal biomass and how much this process would impact the environment. Also, Would there be an overall increase in algae in the water or would the water be filtered out as to always obtain a certain level of algae? This too could altering the ecosystem dramatically.

  2.   lazinskion 16 Jun 2010 at 6:40 am

    Algal biofuels was a hot topic at the conference I attended at Cornell. A lot of graduate students up there are doing research on better harvesting and separating techniques to more easily separate out the lipids from the algae. One promising experimental technique used ultrasound to rupture the algae and have the lipids separate out through gravity. Out of all of the presentations I saw on algal biofuels, the main point I took away was that algae can definitely be a viable fuel source in certain niche markets (like coastal areas), but the whole process of growing, harvesting, and converting algae to fuel has a long way to go and needs to get much more efficient and cheaper. As with many of these technologies, it seems like the development and deployment of algal biofuels is inevitable, and as production ramps up, costs will go down. Algae will definitely play some role in meeting the energy demands of tomorrow.

  3.   Utopia Aquaticon 26 Mar 2011 at 7:51 pm

    Interesting research. We have algae in our ponds but its primarily single-cell and filament.

  4.   Bez Bikon 24 Aug 2012 at 2:32 am

    Everything is very open with a precise explanation
    of the issues. It was truly informative. Your website is very helpful.
    Many thanks for sharing!