Algae on the Edge
The National Renewable Energy Laboratory's Aquatic Species Program identified about 300 species of algae that have the potential to produce thousands of gallons of biodiesel per acre. Researchers and entrepreneurs are on the cusp of bringing this promising technology to commercial production.
The plastic tubes were a one-fifth-scale demonstration of a photobioreactor designed by Solix Biofuels Inc. The lab at CSU is partnering with Solix, a start-up company based in Boulder, Colo., to commercialize a system that, if successful, would create a low-cost feedstock for biodiesel production while removing carbon dioxide and nitrogen oxides from power plant emissions.
Solix plans to develop an algae bioreactor pilot plant in conjunction with a local brewery in 2007 and has plans to scale that up to commercial production in the coming years.
The photobioreactor system was originally developed by Jim Sears, who approached EECL researchers in 2005 with an idea that dated back to the energy crisis of the 1970s: Use oil-rich species of algae to provide feedstock for biodiesel production. Sears and the researchers scaled up his design for a photobioreactor, which is basically a tank to grow algae, to an industrial size while keeping costs low enough to make the system financially viable. Together, Sears and CSU's Doug Henston and Bryan Willson created Solix. Henston is CEO of the company, and Willson is chief technology officer. CSU holds an equity position in Solix.
Oil-rich strains of algae have long been recognized as a potential source of feedstock for biodiesel production. The National Renewable Energy Laboratory (NREL) operated its Aquatic Species Program from the late 1970s to 1996 and identified more than 300 algae strains with economic potential. Some of these algae contain more than 50 percent oil by dry weight and have the potential to produce thousands of gallons of oil per acre, as opposed to a few hundred gallons that can be obtained from an acre of conventional oilseed crops.
"It's not a new technology," Henston says. "NREL, for the better part of 20 years, demonstrated the technology. What's new is essentially 'how do you commercialize this?' How do you develop this so the numbers work out, so there is a compelling business case for developers, for biodiesel producers, for investors, for power plants and for ethanol refiners?"
However, producing an economical product from algae was more complicated than it sounded. "Many people look at the issue of raising algae for biofuels and ask 'How tough can that be?' because you can't keep algae out of ponds or swimming pools," Willson says. "Under natural conditions, algae doesn't grow at a particularly high rate and, in general, doesn't accumulate high amounts of lipids. If you go through the NREL report, you sort of get the idea that you order the right algae, put it in a tank, bubble in carbon dioxide, and you'll be getting oil yields of 10,000 gallons per acre per year. It turns out there are just an incredible number of knobs to turn. Realistically it's very challenging."
NREL tried to breed its algae strains in open ponds in southwestern United States. While high-oil strains of algae are productive, they're not particularly robust. Wild algae carried by birds or the wind would contaminate the ponds. "What they found was the local 'mongrel' algae outcompeted the 'thoroughbred' strains from other areas," Willson says.
Scaling it Up
Growing the algae in closed tanks seemed to be a natural solution to the contamination problem. However, the cost of material, equipment and energy, combined with lower oil prices in the 1980s and '90s made such projects uneconomical. "We believe that what we need to be successful are production systems that allow us to grow existing algae strains at high rates and high lipid contents at low cost," Willson says. "We recognize that, to get high growth rates and high yields, we need to use certain strains of algae."
To keep costs down, Solix's system uses long tubes made of relatively low-cost plastic instead of rigid tanks. Water-weighted rollers act as peristaltic pumps to keep water and nutrients flowing within the tubes. The mixing action allows Solix to make its bioreactor 12 inches deep and still provide light to all the algae. "Systems using glass, stainless steel, rigid plastic tubes-from our economic modeling-all of those don't appear to meet the capital cost requirements that we think we need to meet," Willson says. "So we like to say what we've been working on has been closed-reactor performance at open-reactor costs."
The nutrients within the bioreactor must be carefully monitored to encourage the maximum growth and lipid production from the algae. Like all plants, algae can use carbon dioxide for food in the presence of light. In fact, enriching the growing media with carbon dioxide encourages the production of desirable oils and speeds growth. "The production facilities will have a unique feature in that they will be tied necessarily to point sources of CO2 production, such as power plants or ethanol production," Henston says. "The reason is driven by the technology. We can't just pull CO2 out of the atmosphere. We can't get enough CO2 to produce our algae that way. So, our large production facilities will be centered around greenhouse gas emitters."
Solix's pilot plant, which is slated for construction in 2007, will use carbon dioxide from New Belgium Brewing Company in Fort Collins. The pilot project will include a 350-foot-long by 50-foot-wide unit, covering about one-third of an acre. Carbon dioxide from the brewery's fermentation vats, and exhaust from its boilers, will be used to fertilize the bioreactor.
The goal of the project is to test how well the technology scales to full size, in order to produce enough algae to work on extracting the oil and other valuable coproducts. Willson expects the oil content of the algae in the commercial-scale systems to be about 30 percent. The remainder will contain sugars and cellulose that can be used for ethanol production, and proteins that could be valuable as livestock feed. "This is a many-faceted problem," Willson says. "You have lots of issues related to biology: which algae to use, what media and environment to grow them in, how to entice them to create lipid. On the other side, we have to deal with lots of issues related to engineering in terms of the design of the photobioreactors, design of harvesting and extraction systems, processing the lipids, etc."
If all goes well, Solix could be on track to begin work on a commercial-sized project in 2008. Once it's established, Solix will license its technology to get it to the marketplace quickly. "Where we see this going is the licensing of the technology so we can get as many production facilities out in the market as possible," Henston says. "In order to demonstrate the technology to the market, I use a McDonalds' analogy. Ray Kroc had the idea for the restaurant, built a few restaurants himself to demonstrate it and started licensing the technology, so to speak."
Solix isn't alone in the algae game. At least six strong contenders are working on other algae technologies, and some are working on their own pilot plants, "There are many different technologies," Willson says. "One of the reasons so many people are looking at this is because of the potential of such high benefits."
Greenfuel Technologies Corp. in Cambridge, Mass., has been working on algae production since 2001, says GreenFuel CEO Cary Bullock. In 2004, it installed an algae photobioreactor on a 20-megawatt cogeneration plant at the Massachusetts Institute of Technology. In 2006, it completed construction of an engineering-scale plant at a 1,040 megawatt, coal-fired power plant in Arizona, which will be starting production shortly. "We are trying to get the engineering-scale things done in 2007 so we can start commercial-scale facilities in late 2007 and 2008," Bullock says. "Hopefully, we will have those operational in late 2008."
Researchers with Utah State University's Biodiesel Initiative Group are working on a system that would use vertical photobioreactors to grow algae on polymer membranes, Project Director Byard Wood says. The novel approach in this system is that it uses light-gathering parabolic reflectors to concentrate sunlight on fiber optics. The fiber optics pipe the light into the biorefinery. Wood says one square meter of parabolic mirror can illuminate 10 square meters of algae. The project is examining a number of complementary technologies that could be incorporated, such as anaerobic digestion of cattle manure, to create an integrated biofuels production facility. "The pilot plant should be up and running within two years," Wood says. "The first stage will be built by the end of this year and the second stage by the end of next year. You've got to have a large enough production facility to evaluate the economics of the system. That's what we intend to do."
The Center of Excellence for Hazardous Materials Management, a nonprofit organization located in Carlsbad, N.M., is looking at refining the open-pond concept, says project manager Ron Reeves. The project uses brine from salt-laden aquifers to raise marine species of algae. Since there is little open salt water in New Mexico, the likelihood of contamination is reduced. In 2007, the research center will scale up its experiments by building a 100-acre pond. Its bench-scale demonstrations show potential production in line with NREL results of 5,000 to 15,000 gallons of algae oil per acre per year, Reeves says. The project will provide algae oil to a 3 MMgy biodiesel plant in Carlsbad that is being built by Cetane Energy. "We are on an aggressive schedule," Reeves says. "We believe in being very aggressive and very proactive in everything we do. We are not risk averse. We are willing to gamble and take chances, and have been very successful in doing so."
Aquaflow Bionomic Corp. of New Zealand takes another approach entirely to the contamination problem. It works with native algae that grow in sewage pond discharge, according to the company's prospectus. In 2006, the company extracted lipids from the native algae and used it to make biodiesel. It demonstrated the results publicly by using a 5 percent blend of algae biodiesel to fuel a car that was driven by David Parker, New Zealand's minister for climate change.
More information on projects involving algae can be found at:
Jerry W. Kram is an Biodiesel Magazine staff writer. Reach him firstname.lastname@example.org or (701) 746-8385.