Scientists have speculated that algal fuel could be the magic bullet for fossil fuel dependency, and a new idea by Kansas State University engineers Wenqiao "Wayne" Yuan and Zhijian "Z.J." Pei may make the costs of algae oil production more reasonable.
In the realm of biofuel, alga has attracted interest largely because it grows up to 40 times faster than other plants. Some algae can average more than 6,000 gallons of oil an acre a year — which knocks soybeans, at 50 gallons, out of the water. Excuse the pun.
A big obstacle with algae-derived fuel is that it's not cheap to produce. As a previous Miller-McCune.com article noted, "level of scale and mass production will be the last, and possibly most formidable, mountains to climb."
Current algae-growing methods use ponds and bioreactor columns, but harvesting the algae in these systems is costly. Expenses like centrifuges and electricity are needed to reap the benefits of these moving targets. The end-product biodiesel using the best technologies still costs about $56 a gallon.
Yuan and Pei (who were awarded a National Science Foundation grant this year for their work) have suggested growing algae in the ocean on very large, supporting platforms. The two believe that land used to produce food should not be used to produce algae for fuel. (One of the reasons that the corn-based ethanol bubble popped was the biofuel's effect on the corn market and food prices.)
They are working to figure out which oil-rich algae species can grow in large quantities on a solid surface. Using algae with these traits would simplify the harvesting process and make production manageable.
Yuan said they saw "tremendous potential" for their oceanic ambitions. Half the cost of growing algae is in providing a steady supply of food and water, the growth medium; ocean water offers those in abundance.
Yuan and Pei are trying to determine what makes algae stick to various surfaces, which materials they prefer and what surface textures (if any) encourage them to bloom and grow.
In studies of two algae species that both grow fast and are high in oil, the species got pretty attached to a slightly dimpled, thin-film surface of stainless steel (which is durable, cheap and easy to texture). Once they put down roots, so to speak, they grew very well, producing a clump several millimeters thick. Yes, a thick clump of oily goop means progress.
The researchers envision a long, continuously rolling conveyer-belt-like surface for algae production. If you'd like a mental picture, imagine a gigantic airport security X-ray machine on the ocean, with a dimpled, stainless-steel conveyer belt covered in algae. At some point, the algae underneath the water will roll up into the sunlight (where you would theoretically place your carry-on) to dry. Instead of going under the X-ray for examination, the dried algae will be scraped off by a harvesting knife, and the surface will be re-submerged for the next growth cycle.
Yuan predicts that it will be five to 10 years before scientists know enough about large-scale algal production to reduce costs to the target of around $5 a gallon. He says it will take that much time to understand the fundamentals and establish pilot projects.
One pilot project, a joint project led by Australia's Murdoch University along with the University of Adelaide, is achieving the world's best production rates of oil from algae grown in open saline ponds. The project now leads world algae biofuel research, having achieved consistent results for over 12 months at both universities. Construction on a multimillion-dollar pilot plant in Australia to test the whole process on a larger scale is slated to begin in January.
Project leader Michael Borowitzka from Murdoch University predicts the high production rates (50 metric tons per hectare per year, over half of which is converted to oil) are expected to increase at the new pilot plant.
There has already been significant investment in the development of algal biofuel. Miller-McCune.com has followed the developments of startup Sapphire Energy, as well as the progress of Biodiesel Industries, which has developed a self-contained biodiesel fuel production system. We also mentioned an at-home biodiesel how-to guide.
Whether or not you choose to make algae biodiesel in your backyard or the beach, the advances in the field indicate that an algae conveyer belt in the sea may not be pie in the sky.
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