Southwest Environment

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Department of Soil, Water and Environmental Science
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Algae fuels efforts to reduce air pollution

diesel gas pumpsWith federal regulations restricting pollution from diesel fuel, more drivers may turn to biodiesel to meet standards.

By Cassie Fausel, May 11, 2010

Algae is not just the substance that clouds your fish tank or the slime you feel along rocks on vacation. With today’s technologies, it can be harvested to produce biofuel.

University of Arizona researchers are “growing algae to putting fuel in your tank,” said Kimberly Ogden, principal investigator on a $2.4 million UA project to convert algae into biofuel. “You can do it now, but the cost is prohibitive. We’re looking at 10 to 15 years until it’s in your tank.”

The UA project, in the Department of Agriculture and Biosystems Engineering, is part of a $44 million nationwide consortium granted to the National Alliance for Advanced Biofuels and Bioproducts. The NAABB received funding from the U.S. Department of Energy to develop efficient ways to harvest algae to fuel vehicles.

The universities nationwide will “focus on diesel and co-products. We’re looking at the big picture such as biofuel, jet fuel, and what do you do with the rest of the protein, and the fundamentals of the algae,” said Ogden, who serves as executive engineer for the nationwide grant as well as principal investigator for the UA research team. 

Currently, the method to harvest algae involves a centrifuge, which spins algae in water at extreme speeds, separating the fats from the proteins. The fat-based oils, specifically lipids, are the main component of the biofuel.  

These lipids can help reduce pollutant emissions compared to conventional diesel fuel. That’s because some of the nitrogen that could otherwise form the pollutant nitrous oxide will be centrifuged out of the mixture.

“It will end up in the protein fraction instead of the lipids,” Ogden said. The leftover protein can supplement livestock feed, she added, as long as the water was not from a contaminated source.

As well as emitting less nitrous oxide, biodiesel produced from algae is non-toxic, biodegradable, and contains no sulfur, she noted. The lack of sulfur could help diesel consumers meet new Environmental Protection Agency standards.

The EPA’s National Clean Diesel Campaign has sparked efforts nationwide to reduce air pollution. By December 2010, the EPA will require diesel vehicles to use ultra low sulfur diesel (ULSD). In the early 2000s, sulfur emissions from diesel engines averaged about 500 parts per million. By the end of 2010, diesel fueled vehicles must have lowered sulfur emissions to 15 part per million.

To start preparing for the regulation changes, diesel enthusiast Cory Worischeck of Tucson currently switches between petroleum diesel and biodiesel, which is also low in sulfur. Arizona currently sells Biodiesel-20, which includes 20 percent alternative fuels, usually ethanol made from corn or soybeans.

“Biodiesel-20 lubricates the engine, but it is not as efficient because there is not as much potential energy in an ounce of biodiesel as there is in an ounce of regular diesel number 2,” Worischeck said.

With the new standards, the diesel consumer is posed with the challenge of spending more money on fuel in order to get from point A to point B. Worischeck and others would prefer a less expensive way to comply with EPA standards.

Ogden and her team are working to make algae a more affordable biofuel. As the technology of harvesting algae as a biofuel already occurs on a small scale, the major issue is to develop an economically feasible way to harvest algae at a large scale.

“Algae is where the future is going, but the hardest is the harvesting costs,” Ogden said.

Petro Sun, a Phoenix-based company that collaborated with the UA in pursuit of a grant, is conducting similar research on cleaner fuels. The company notes on its Web site that algae can yield about 30 times more oil per acre than corn and soybean crops. Ogden agreed, adding, “You can grow the algae for 48 to 72 hours and harvest,” unlike corn and soybeans, which are seasonal.

Algae can grow continuously, with a never-ending harvest season. So, while it may look like slime, Kimberly Odgen, Cory Worischeck and others see it as a worthwhile substance to explore for the potential benefit of the environment.


National Alliance for Advanced Biofuels and Bioproducts

EPA National Clean Diesel Campaign

EPA Transportation and Climate, Regulations and Standards

Cassie Fausel is a University of Arizona student majoring in Environmental Science with a focus on policy and soils. She believes that translation of science is one of the most important skills an undergraduate can learn. She is currently completing research in the ocean of Biosphere 2, a research site affiliated with the UA. 

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