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Algal Biofuels
Algal biofuels, a type of third-generation biofuel1 also commonly called algae biofuels, refers to a number of processes available and in development that cultivate and then breaks down a species of algae into lipids, triglycerides, proteins, and carbohydrates2. The lipids and triglycerides, the same material found in vegetable oils, are then refined into jet fuel, biodiesel, or green diesel. The proteins and carbohydrates can be processed into ethanol, combustible material, methane, or animal feed that is high in Omega 3 fatty acids. The fuels produced from algae must meet the same American Society for Testing and Materials (ASTM) standards as other biofuels. Algal biofuels are further considered a “drop-in” fuel because no system modifications are required to switch between traditional fossil fuel and algal biofuels in engines or transport lines.
Algal biofuels are particularly appealing because they have over 50% lipid content, found in any organic species that can be converted to triglycerides and refined into biofuel3. Algae also grow rapidly; some species can double in a number of hours. High lipid content and growth rates allow algae to produce 10x-100x as many lipids per acre than terrestrial organisms. If the land area devoted to soy-based biofuel cultivation in the United States was converted to algal biofuel production, it would account for 61% of the annual diesel used in the United States whereas the soy only meets 4% of demand4. Algae is not the most productive organism though, bacteria and yeast can be ten to twenty times as dense thus if biofuel could be extracted from those organisms a new opportunity would open5.
Additionally, algae can be cultivated in harsh conditions, such as deserts as to prevent competition for arable land. Alga is not a food crop and thus avoids the controversy often associated with corn or soy based biofuels that some view as ethically questionable because the crop is not being used for food. Watersheds are not immediately at risk from algae cultivation either. Algae can be grown in salt, brackish, or fresh water6. A key risk to any watershed would be in the handling of salinification from a spill or wastewater7. If accounted for in design however, algae can treat wastewater. Also, alga is a carbon-fixing organism. For example, if located near a coal power plant, the algal beds can recycle the carbon emissions from the plant therefore using it twice before it is released into the atmosphere, which would increase the energy produced per unit of CO2 by approximately 60%. Each gram of algae needs an input of 2g of CO2. Algae cannot however sequester carbon permanently unless it is stored somewhere permanently and cannot decompose8.
The capacity to capture carbon and treat wastewater offer ways to decrease operating costs for algal biofuel production if located near a power plant or farm. Cost reduction is key to the viability of algal biofuel’s success on the market. If algal biofuel is priced higher than soy or fossil fuel, it looses its competitive edge regardless of the quantity it can produce per acre. As of 2008 algal biofuel is competitive with soy-based biofuel only at high productivity projections. Algal biofuel is further competitive with oil at $110 or greater per barrel as of 2008 but there are no commercial algal biofuel production facilitates in the United States9.
History of algal biofuels in the United States
Algae is used in fertilizer, cosmetics, nutraceutical, pharmaceuticals, food supplements, and aquaculture. Algae also stabilize dairy products, pet foods, and toothpastes10. The earliest mention of algae as a potential biofuel originated from a 1950s MIT report concerning a rooftop project where algae was cultivated in bulk11. The appeal of research and development (R&D) is highest when petroleum is more expensive. After the energy price spike during the 1970s, the United States Department of Energy (DOE) and National Renewable Energy Laboratory (NREL) were federally funded $25 million to research which species of algae are most productive, engineer a GMO that was most efficient, and test open and closed methods of cultivation for cultivation and cost efficiency12. The funding for that program was pulled after 18 years in 1996 though due to federal budget cuts. As of 1995 algal biofuels cost 2-3 times as much per barrel as crude oil, which was $20 per barrel13. Algal biofuel development did not terminate though, as laboratories and private industry continued work.
The Energy Independence and Security Act of 2007 and the American Recovery and Reinvestment Act from 2009 have produced new funding for algal biofuel R&D through National Alliance for Advanced Biofuels and Bioproducts and National Advanced Biofuels Consortium14. Algal biofuel is key in meeting the 36 billion gallons per year goal set for biofuels in 2022 by president Obama. To facilitate the R&D, many projects have been funded and an inter-agency working group for Biofuels assembled including United States Department of Agriculture, Environmental Protection Agency, DOE, and public private partnerships15. January 13, 2010 federal and non-federal matching funds of $78 million were allocated to commercialize algal biofuels and further research hydrocarbon fuel production through processing of left over biomass16. Indicating growing interest, the DOE held an Algal biofuels workshop in 200817.
Private interests have emerged as well. In July of 2009, Exxon dedicated $600 million to a five to ten year project expected to produce 2,000 gallons of biofuel per acre. Shell and Chevron have investigated similar possibilities18. Defense organizations such as Air Force Office of Scientific Research and Defense Advanced Research Projects Agency, have also committed to algal biofuels through collaboration with NREL19. Continental Airlines flew a test flight of a 737 in 2009 with one engine running 50% algal biofuel, finding that it produced les emissions and provided similar flight quality to traditional jet fuel. Algal biofuel also falls within flash point and freezing point standards for use in jetliners20. KLM-Air France signed an agreement to an algae oil producer in 2008 to implement use of mixed fuel.
In 2010, the Defense Advanced Research Projects Agency (Darpa) announced that it had been able to extract oil from algae at the cost of $2 a barrel, and that they were developing methods to refine it into jet fuel at an anticipated price of $3 per barrel. This new development would make algal biofuels cost competitive with conventional fossil fuels. Darpa stated that they would begin testing the process in 2011, with the aim of being able to produce cheap fuel from algae by 2013.21
International history of algal biofuels
An international effort came to fruition in Japan between 1990 and 2000 in the form of a photobioreactor. The cost of the project, $1,000 per square meter, was so high though that the project was deemed a complete failure22.
Significant projects concerning biofuel exist in the Middle East.
In the European Union, algal biofuels fall under the European Biodiesel Board23.
In the United Kingdom, the Scottish Association for Marine Science is seeking to use marine organisms to produce primarily methane. The Carbon Trust, a university in the UK is funding research into the commercialization of algal biofuel by 202024.
A corporate social responsibility partnership between coal and algal energy companies emerged in 2008 in Australia25.
DOE and Israel are collaborating on R&D after the Energy Independence and Security Act.
China is beginning the pilot stage of a 2,880 acre algal biofuel farm in 2010 with XL Renewables, expected to produce 16 million gallons of algae oil annually; the input cost for which is 5-7 million dollars per acre26. Another 110 acres has been awarded to Algae LLC near an industrial site.
KLM-Air France signed an agreement to an algae oil producer in 2008 to implement use of mixed fuel27.
The 2010 Algal Biofuel Workshop is being hosted by India28.
Algae type selection
Both macro and micro algae can be used to produce biofuels. There is a lower cost of cultivation and harvesting for macro algae but they produce fewer lipids. Micro algae on the other hand, are more cost intensive in terms of cultivation and harvesting but contain large amount of oil. Each type of cultivation is best suited for a certain types of alga29. Some algae can even be cultivated without light in heterotrophic conditions with the input of sugar as a nutrient30. Light is however, a limiting factor for most alga biofuel production methods thus they are less productive in winter months31. Micro algae are most commonly used for biofuel to date. Different types of micro algae produce different quantities of the material required for its products. Consequently, different strains of micro algae are more appropriate for producing ethanol32.
Cultivation methods
Open Pool - Liners can hold nutrients and circulation can be achieved with a paddle although it is not necessary. A potential environmental concern of open cultivation is that in large enough scale, the humidity produced from evaporation could alter the microclimate of an area33.
Photobioreactor - All nutrients are artificially introduced. Algae are grown in tubes with a natural or artificial light source. Can grow many species at once. Limits competitors and pathogens. If heated, can produce for full calendar year. Internally cleaned thus not required to stop production to clean34.
Closed Pool - Less expensive than Photobioreactors but can create longer growing season than open systems because ponds are housed in a green house, which can be heated. Still increases energy input costs if heated35.
Heterotrophic - No light used in cultivation. Potentially increases carbon footprint because sugar must be added as a nutrient36.
Marine - Macro algae can be artificially introduced to a surface in the ocean or an artificial marine environment maintained by creating the same composition of salts found in ocean water. Marine cultivation can be very cost efficient Open ocean cultivation is primarily practiced in Asia for seaweed products not related to biofuel by using nets to capture algae37.
Threats to production
Competitors, grazers, and pathogens must be removed periodically by shutting down the cultivation system for a several days38.
Harvesting is 20-30% of production cost. Methods such as gravity settling although slow are most cost effective and would avoid the introduction of environmentally harmful chemicals39.
Extracting oil is most economical with paste instead of dried algae. Fuel conversion may be difficult to keep consistent though given variances in lipids that can be caused by climate or algae type40.
Footnotes
1. Caitie Ryan, Cultivating Clean Energy: The Promise of Algal Biofuels(pdf), Energy Issues section, NRDC (October 2009). Accessed Feb 28, 2010.
2. Al Darzins, The Promises and Challenges of Algal Derived Biofuels: Clean Cities Webinar , NREL (October 2009). Accessed Feb 28, 2010.
3. United States Department of Energy, Biomass Program: Algal Biofuels, Accessed Feb 28, 2010. Accessed Feb 28, 2010.
4. Philip T. Pienkos and Al Darzins, The Promise and Challenges of Microalgal-Derived Biofuels, AFDC (May 2009). Accessed Feb 28, 2010.
5. Philip T. Pienkos and Al Darzins, The Promise and Challenges of Microalgal-Derived Biofuels, ASDC (May 2009). Accessed Feb 28, 2010.
6. Al Darzins, The Promises and Challenges of Algal Derived Biofuels: Clean Cities Webinar , USDOE (October 2009). Accessed Feb 28, 2010.
7. Caitie Ryan, Cultivating Clean Energy: The Promise of Algal Biofuels, NRDC (October 2009). Accessed Feb 28, 2010.
8. Philip T. Pienkos and Al Darzins, The Promise and Challenges of Microalgal-Derived Biofuels, AFDC (May 2009). Accessed Feb 28, 2010.
9. Philip T. Pienkos and Al Darzins, The Promise and Challenges of Microalgal-Derived Biofuels, AFDC (May 2009). Accessed Feb 28, 2010.
10. Oilgae, Uses of Algae as Energy Source, Fertilizer, Food, and Pollution Control, (February 2009). Accessed Feb 28, 2010.
11. John R. Benemann, Overview: Algae Oil to Biofuel, NREL (February 2008). Accessed Feb 28, 2010.
12. Al Darzins, The Promises and Challenges of Algal Derived Biofuels: Clean Cities Webinar , USDOE (October 2009). Accessed Feb 28, 2010.
13. Philip T. Pienkos and Al Darzins, The Promise and Challenges of Microalgal-Derived Biofuels, AFDC (May 2009). Accessed Feb 28, 2010.
14. Biomass Program: Algal Biofuels, USDOE. Accessed Feb 28, 2010.
15. Growing America’s Fuel: An Innovation Approach to Achieving the President’s Biofuels Target, (February 2010). Accessed Feb 28, 2010.
16. , DOE Awards Nearly $80 Million for Biofuels Research and Infrastructure, USDOE (January 2010). Accessed Feb 28, 2010.
17. Biomass Program: Algal Biofuels, USDOE. Accessed Feb 28, 2010.
18. ExxonMobil Plans to Grow Algae for Biofuel, USDOE (July 2009). Accessed Feb 28, 2010.
19. Biomass Program: Algal Biofuels, USDOE. Accessed Feb 28, 2010.
20. Bill Henesl Jr, Continental Jet Makes Biofuel Test Flight, (January 2009). Accessed Feb 28, 2010.
21. Suzanne Goldenberg, "Algae to solve the Pentagon's jet fuel problem," UK Guardian (February 2010). Accessed May 4, 2010.
22. John R. Benemann, Overview: Algae Oil to Biofuel, NREL (February 2008). Accessed Feb 28, 2010.
23. Oilgae, Comprehensive Oilgae Report: Report Preview, (January 2010). Accessed Feb 28, 2010.
24. Oilgae, Comprehensive Oilgae Report: Report Preview, (January 2010). Accessed Feb 28, 2010.
25. Oilgae, Comprehensive Oilgae Report: Report Preview, (January 2010). Accessed Feb 28, 2010.
26. Solix supplying algal biofuel samples. (2010, February). International News on Fats, Oils and Related Materials : INFORM, 21(2), 84. Retrieved February 28, 2010, from Sciences Module. (Document ID: 1965371421).
27. Oilgae, Comprehensive Oilgae Report: Report Preview, (January 2010). Accessed Feb 28, 2010.
28. Growdiesel Fuel Forever, Algae Biofuel Workshop 2010, (February 2010). Accessed Feb 28, 2010.
29. Oilgae, Comprehensive Oilgae Report: Report Preview, (January 2010). Accessed Feb 28, 2010.
30. Caitie Ryan, Cultivating Clean Energy: The Promise of Algal Biofuels, NRDC (October 2009). Accessed Feb 28, 2010.
31. Solix supplying algal biofuel samples. (2010, February). International News on Fats, Oils and Related Materials : INFORM, 21(2), 84. Retrieved February 28, 2010, from Sciences Module. (Document ID: 1965371421).
32. Oilgae, Comprehensive Oilgae Report: Report Preview, (January 2009). Accessed Feb 28, 2010.
33. Oilgae, Cultivation of Algae in Open Ponds, (February 2009). Accessed Feb 28, 2010.
34. Oilgae, Cultivation of Algae in Photobioreactor, (February 2009). Accessed Feb 28, 2010.
35. Oilgae, Cultivation of Algae in Closed Ponds, (February 2009). Accessed Feb 28, 2010.
36. Caitie Ryan, Cultivating Clean Energy: The Promise of Algal Biofuels, NRDC (October 2009). Accessed Feb 28, 2010.
37. Oilgae, Cultivation of Algae in Marine Environment, (February 2009). Accessed Feb 28, 2010.
38. Philip T. Pienkos and Al Darzins, The Promise and Challenges of Microalgal-Derived Biofuels, AFDC (May 2009). Accessed Feb 28, 2010.
39. Philip T. Pienkos and Al Darzins, The Promise and Challenges of Microalgal-Derived Biofuels, AFDC (May 2009). Accessed Feb 28, 2010.
40. Philip T. Pienkos and Al Darzins, The Promise and Challenges of Microalgal-Derived Biofuels, AFDC (May 2009). Accessed Feb 28, 2010.
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