Arizona’s Algae Biofuel Research Advances Understanding, Technology

Return to AWR Fall 2014

Arizona is taking advantage of its open land and ample sunshine to assume a leadership position in the algae biofuel field, although farming algae can use a great deal of water. Algae shows great promise as a source for alternative fuels, as well as other useful products, and commercialization is a high priority for the U.S. Department of Energy.

Arizona is home to two national algae testbed programs for research and development, funded in large part by grants from the Department of Energy. An $8 million grant to the University of Arizona is enabling UA to try out its proprietary algae farming system in other states to see how it functions in different conditions. A previous $15 million grant to Arizona State University allowed the establishment of a national test bed, providing facilities for algae biofuel work. Projects that began in 2013 are promoting advances in algal technology and data collection while stimulating workforce development. But what about the technology’s water footprint?

Much of the new work is in response to a report issued in 2012 by the National Research Council warning that an increase in algae-based biofuels to as little as 5 percent of the U.S. transportation fuels market “would place unsustainable demands on energy, water and nutrients.” The amount of resource use depends on the method used, including what type of water the algae is grown in—salty or fresh—and whether grown in closed or open systems, where evaporation is an issue. Estimates for water use range from 3 gallons of water per gallon of algal biofuel produced to a thousand times that quantity.

Scientists are working to reduce resource use and with it the cost of production—the most significant barrier to commercialization. A gallon of algae fuel is estimated to cost more than $20, and algae fuels would have to be produced at a cost to consumers closer to the cost of gasoline, under $4 per gallon, before a market is likely to develop. Scientific advances are aimed at making the production of algal biofuel less costly. Some new designs being tested use wastewater, which provides both water and nutrients. Others capture carbon dioxide from the burning of fossil fuels to stimulate algae growth while reducing carbon emissions. Other activities focus on the type of algae and the characteristics that make it optimal for fuel production.

Algae are simple, plant-like organisms that grow all over the world in seawater, freshwater and wastewater. Although the total number of species is unknown, more than 40,000 have been identified and most use sunlight to make their own food. Half of algae’s composition can be lipid oil, and algae contain protein and carbohydrates, so the plants can be used for both fuel and food. Because of their efficient use of light and nutrients, their potential for biofuel production is much greater than other crops, such as corn. Other potential advantages over the use of land plants for biofuel include algae’s ability to grow where other crops are not grown and to grow in salt water or wastewater. Water use for corn-based ethanol is similar to some of the algae-based biofuel alternatives.

At ASU, a collaboration with the National Renewable Energy Laboratory, Sandia National Laboratories, Cellana LLC, Touchstone Research Laboratory, SRS Energy, Cal Poly San Luis Obispo, Georgia Institute of Technology, University of Texas at Austin, and Commercial Algae Management is supporting work on selected strains of algae in open or closed systems using various water sources. Research is also performed to improve methods for collecting and extracting the oil from algae and for processing the oil into fuel. The Department of Energy-funded collaboration is led by the Arizona Center for Algae Technology and Innovation (AzCATI) in the Polytechnic School at ASU. At this first national algae testbed, facilities support research, testing and commercialization of biofuels and other algae-based products, such as pharmaceuticals and nutraceuticals, by the algae industry and research community. Created under a Science Foundation Arizona grant in 2010, AzCATI has since developed more than $22 million in research projects.

At UA, water usage and quality issues are receiving research attention, along with design of algae production facilities and development of superior algae strains. The Regional Algal Feedstock Testbed (RAFT), a research partnership led by UA, is exploring the potential for growing algae in different climates using UA’s open-air algae farming system, the Algae Raceway Integrated Design (ARID). The other RAFT partners include Pacific Northwest National Laboratory, New Mexico State University and Texas A&M AgriLife.

ARID was used to determine the optimal temperature for algae growth and has a unique design that can sustain growth year-round in a temperature-controlled environment. It recycles water through its serpentine canals and only adds water when needed to control temperature or for harvesting and cleaning. The RAFT is comparing ARID with other designs to identify the best-performing systems in different parts of the country. Results of an evaluation published in October 2013 described ARID’s superior economic potential over open ponds. The ARID system located in Tucson is available for use by researchers from elsewhere for other algae projects.