The U.S. DOE’s National Renewable Energy Laboratory has a rich history when it comes to algae research. Its landmark program, known as the Aquatic Species Program, is commonly considered the bedrock of the modern algae industry. While the program was discontinued in 1996, the close-out report NREL researchers complied at its sunset is still considered to be the primary source on algae for companies entering the sector. Algae research was revived by NREL in 2006, and has since achieved many promising benchmarks.
The Aquatic Species Program was quite well known for as establishing the state of technology for algal biofuels, says Phillip Pienkos, acting group manager of the applied sciences group at NREL. “It was a comprehensive effort applied across the entire value chain,” he says, from basic biology and bioprospecting, to strain improvement, cultivation, harvesting, conversion and economic analysis.
At the time the program was discontinued, even the most optimistic analysis of available data showed algae biofuels were still far too expensive to compete with petroleum. “The most optimistic projection was somewhere on the order of $40 per barrel for algae oil, compared to the price of petroleum, which was about $20 per barrel [at that time],” Pienkos says. “The best prognostication of that period suggested that oil was going to remain at $20 per barrel for the foreseeable future.”
“The low cost of petroleum really took the wind out of the whole biofuels arena,” Pienkos continues. “The DOE decided to cut back on funding, end the algae program, and focus [almost exclusively] on cellulosic ethanol. Of course, the foreseeable future ended a lot sooner than anyone expected.”
By 2008, the price of oil had reached all time highs. “As we were moving in that direction, there was a sense that we really needed to reevaluate our commitment to biofuels,” Pienkos says. In 2006, the DOE and USDA produced a report that has widely become known as the “Billion Ton Study.” The report determined that the U.S. could produce approximately 1 billion tons of terrestrial biomass each year. According to Pienkos, analysis clearly showed that terrestrial biomass could not alone meet our nation’s fuel needs, especially when one considers that that biomass is a sought-after feedstock for many other industries, including the heat and power sectors.
“When that study was done, it became clear at NREL and at other places that there was perhaps a need to reevaluate the decision that was made to end research into algal biofuels,” Pienkos says. In 2006, it was decided to bring NREL back into the game.
While petroleum companies traditionally showed little interest in cellulosic ethanol, NREL anticipated it might be interested in forming partnerships for algae research. Indeed, the oil industry did show interest, due in part to the fact that algal lipids make a better feedstock for their refinery operations.
A research agreement was established with Chevron in 2007, breathing life back into NREL’s algae program. “That really helped us get back on the map,” Pienkos says. “Although as a flagship program, [cooperative research and development agreements] are rather unsatisfactory because we can’t really talk about the work. Our management and scientific leaders here at NREL recognized the value of algal biofuels, and NREL made available internal funding to allow us to make some strategic capital purchases and do some remodeling of our labs to restore our ability to grow algae and actually support some research projects. Through this internal funding, we began to build a series of projects that we could actually talk about and help better establish ourselves as a lead organization in algal biofuels.”
NREL’s primary focus in algae research is biology. “There are a number of reasons for that,” Pienkos says. “If you do economic modeling and you do sensitivity analysis, you see that the biological productivity [of algae] is by and large the major cost lever for algal biofuel production.” There are a lot of numbers and goals tossed around when it comes to productivity and lipid content, however, the ranges most often cited by industry ultimately result in huge changes in the calculations and projections of the cost per gallon of algae oil. “That drives a lot of people to the basic biology,” Pienkos says. One reason NREL is here, he adds, is to help identify how to achieve high growth rates, while achieving high lipid content.
One internally funded NREL project focuses on finding better ways to extract lipids from algae cells. The project led by NREL researchers Eric Knoshaug and Henri Gerken, centers on the use of enzymes.
“It’s difficult to get oil out of the algae,” Pienkos says. “Extraction requires things like dewatering the cells to the point of dryness. Even with that, you can’t necessarily count on the solvents getting into the cell and being efficient at extracting the oil.” The use of solvents also generally requires a great deal of energy, in terms of mixing or disrupting the cell walls.
“One thought that we had was if you found enzymes that could help degrade the cell wall, that would facilitate the extraction of the lipid,” Pienkos says. “It might also allow the lipid droplets to simply escape from the cell so that you might not even need solvents.”
There are two possible ways to exploit the use of these enzymes. “One is to take your algae and concentrate them some way in an aqueous slurry, throw enzymes in and weaken the cell wall to get the oil out,” Pienkos says. “Another way is actually to engineer the algae so that under controlled conditions they produce those enzymes themselves. You would harvest the cell, process it in some way, and all of a sudden they would begin to weaken their own cell walls, [which would] reduce the cost and the energy necessary for lipid recovery.”
While Knoshaug and Gerken are working on methods to more efficiency extract oil from algae cells, Lee Elliott, a PhD candidate at the Colorado School of Mines who works as a researcher at NREL, has been traveling around the Southwest collecting native algae strains.
The project Elliott is leading was funded by the Colorado Center for Biofuels and Biorefining (C2B2). During the summers of 2008 and 2009, Elliott collected more than 70 water samples from areas in California, Nevada, Utah, Colorado, New Mexico and Arizona.
Back at NREL, he worked to isolate algae strains found in the water samples, resulting in about 360 individual isolates. Once the strains are isolated, they are screened to identify promising strains in terms of lipid production and growth rates.
The bioprospecting portion of Elliott’s project is now complete, but a similar project is under development to collect strains from regions in Canada. That research is being developed through a partnership formed between the DOE and the Canadian National Research Council.
Elliott says he should be done screening the algae samples he collected by the end of the year. It has not yet been determined who will have access to the samples once lipid screening is complete. “Other people are interested in screening this [collection] in more detail and for other products,” Elliott says. This includes screening for carbohydrate levels, characteristics relevant to hydrogen production, and protein content. In addition, Elliott notes that some may be interested in screening for toxins. A lot of algae produce toxins that may actually be valuable, he says.
Another NREL researcher is working to develop a mathematical model that could expedite the process to measure the lipid content of algae cells. “My work is mainly focused on understanding the biochemical composition of microalgae biomass,” says Lieve Laurens, a research scientist in NREL’s National Bioenergy Center.
Laurens uses near infrared spectroscopy to determine the composition of algae samples. The testing method is allowing Laurens and her team to develop mathematical equations that can predict lipid content based on a spectra fingerprint.
Traditionally, the lipid content of algae cells has been measured by using highly toxic and carcinogenic solvents to extract the oils. After the oil is extracted, gas chromatography is used to analyze the individual lipid types present in a biomass sample. The entire process is extremely labor intensive and can take several days to complete, Laurens says.
Spectroscopic fingerprinting, on the other hand, takes a matter of seconds. Using the mathematical models Laurens and her team are developing, the lipid content of an algae cell can be estimated in under a minute.
The completion of a feasibility study was the first step in developing the prediction models. The results of that study were published last year. Since that time, work has continued, and Laurens says the project is progressing nicely. “The more samples we collected, the more fingerprints we have,” she says. “For all these samples, we also have the actual measured concentrations [of oils]. So, now we have models we can actually apply to new samples as well.”
While there is still a bit of uncertainty associated with the mathematical models, Laurens says her team is working to improve them and reduce the level of uncertainty. One clear benefit of the method is that it is nondestructive. This means that the algae cells aren’t destroyed during the evaluation.
The method being developed by Laurens and her team is clearly beneficial in a lab setting, where researchers need to process a large number of samples as quickly as possible. However, the models might also be useful in commercial applications. Those who produce algae commercially will need to have a method to monitor lipid content in real-time so that they can determine the optimal time for harvest. Near infrared spectroscopy could allow commercial-scale producers to take a sample of their algae culture and determine its lipid content in a matter of minutes.
Into the Future
Now that NREL is back in the algae game, Pienkos says he expects the lab to continue to be a leader in the industry. “I think [algae] is an ideal subject for NREL research because there remains a lot of technical hurdles, and there remains quite a bit of uncertainty,” he says. “Although there has been a significant amount of large-scale investments in algae, there still remains a lot of uncertainty in the short-term, and with commercialization in general.”
Many of the technical hurdles identified during the Aquatic Species Program still remain, he continues, noting the best cost projections still show that algae is too expensive to compete with oil. That said, Pienkos continues, the strategic value of algal biofuels when it comes to energy security implications and greenhouse gas reductions is far too important to pass us. “We need to continue doing this work, even it if takes years to accomplish, simply because the need is so great,” he says. “And the risk is high enough that you can’t expect private industry and private investors to necessarily shoulder the burden.”
The government and national labs can really help the entire industry move forward by helping to reduce risk and stimulating private investment, Pienkos adds. “I think algae biofuels are going to require a bit more R&D,” he says. “Some of the R&D, especially in the algal biology falls into a sweet spot for our research, so I think that we have an important role to play in accelerating the path to commercialization.”
Regarding the future of the algae industry as a whole, Pienkos says that he thinks the new wave of companies entering the space has already peaked. What we’re seeing now, he says, is some new companies entering the space and very quickly taking prominence. In many cases, those are companies that have either developed a game-changing technology or have identified a niche in the field that allows them to stand out.
Rising oil prices are certainly helping to drive all forms of biofuel research. “There is no question about that,” Pienkos says. However, it is important to ensure algae companies are cost competitive with low petroleum prices. “The worst that could happen,” he says, “would be for an undercapitalized company to make its move towards commercial production and then have the price of oil depressed for a period of time, driving them out of business.”
Author: Erin Voegele
Associate Editor, Algae Technology & Business