From Petri Dish to Gas Pump

Some commercial adventurers are considering topping off their tank with pond scum, an approach that gains currency as other biofuels lose some luster.
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Some commercial adventurers are considering topping off their tank with pond scum, an approach that gains currency as other biofuels lose some luster.

In a comic book world, a superhero single-handedly addresses the ills of the world. Now imagine a simple organism simultaneously tackling three of Earth’s nagging problems: air pollution, global warming and depletion of energy supply.

The organism with this potential is the lowly alga, sometimes known as pond scum. Since the dawn of time, it has been ready for its “15 minutes.”

Chemists, fuel companies, venture capitalists and public utilities are looking to harness alga’s potential as an eco-friendly and economical biofuel as well as an answer to those pesky flue gas emissions. Their efforts come as other bio-fuels, such as corn-based ethanol, face concerns that they help create more climate woes than they solve.

Microalgae (to distinguish it from such macroalgae species as seaweed) have many desirable attributes for energy producers. Their oil content, in the form of molecules known as lipids, can be as high as 80 percent in dry weight, although 40 percent is more the average — still easily higher than any other biomass feedstock being considered today. Algae reproduce exponentially and can grow about anywhere. In fact, algae prefer salty and sunny conditions, opening up the possibility of using desert and marginal agricultural land for production of algal feedstock. They can even grow in wastewater, and they thrive on carbon dioxide from gas- and coal-fired power plants.

Indeed, they may be the original multitaskers.

Keith Cooksey, a professor emeritus at Montana State University, was researching ways of removing algae from U.S. Navy vessels more than 20 years ago when he became interested in separating lipids from algae. While doing a literature search, his wife saw an article on how lipids were being detected in human cells. Cooksey decided to see if the same process would work with algae.

He developed a method of staining the cells to determine lipid content. Using a dye called Nile red, he was able to reduce the sample size needed, making the detection of oil in the microscopic plant feasible. Much of his research was conducted with grants from the U.S. Department of Energy’s (DOE’s) Aquatic Species Program. An executive summary of the project’s work in 1998 concluded that algal fuel was not yet economically feasible, and the project lost funding.

End of story — until 2007, a year that saw the price of oil near $100 a barrel, Al Gore and climate scientists win the Nobel Prize for their global warming call to arms and several coal-fired power plants nixed by state regulators.

Cooksey recently attended an algal fuel conference in San Francisco that attracted 300 people. The national press has taken notice, with stories in The Washington Post and BusinessWeek. Sandia National Laboratories is looking into developing algal oil as a military jet propellant. And the U.S. Air Force Office of Scientific Research has partnered with the DOE's National Renewable Energy Laboratory to bring scientists, including Cooksey, together to assess the state of today’s algal fuel research.

Meanwhile, Cooksey has received several calls from academic and commercial entities asking about “tweaking” the Nile red procedure. “In the last few months, I’ve had more than 30 requests for information,” he said, “mainly from small companies who want to improve their research and from some who want to start something on algal biodiesel production.”

So what are the downfalls of this unexpected wunderkind? Feedstock is needed on a mass scale. Separating the water from the algae and leaving the oil remains a challenge. Sometimes the algae’s exponential growth overwhelms its human keepers. Various strains of algae are being tested to determine compatibility with different processes and uses. And, as with all new technologies, level of scale and mass production will be the last, and possibly most formidable, mountains to climb.

The field has an expectant and secretive air to it, with companies declining to provide interviews citing proprietary issues. Cooksey commented on his experience at the San Francisco conference: “No one will tell you anything.”

Several approaches are being researched, with the trend turning away from open ponds because of lower-than-expected yields of algae. Today’s research involves photobioreactors and fermentation processes, methods for identifying the most productive strains of algae and use of carbon dioxide emissions to feed the algae and sequester carbon in both gas- and coal-fired power plants.

The switch to bioreactors has made determining how much land and capital might be required for industrial-scale biofuel production an open question. Michael Briggs, a physicist at the University of New Hampshire, made some estimates for replacing imports of foreign oil in a 2004 paper, but four years later he’s backed off those optimistic estimates as it’s become obvious that commercial production will rely on more costly enclosed processes.

Still, when compared to use of corn, rapeseed or soy, the other main biofeedstocks, creating algal fuel can be done much faster because algae grows so fast — up to 40 times faster than other plants. Ron Pate, a technical expert at Sandia National Laboratories, has been quoted as saying algae has the potential to deliver 10 or 100 times more energy per acre than currently used energy crops. Other sources put it at 140 times.

Solazyme, a San Francisco-based synthetic biology company, recently announced it had road-tested the first algae-derived biodiesel in a factory-standard automobile over long distances under typical driving conditions. Chief Executive Officer Jonathan Wolfson said the company signed a development and testing agreement with Chevron Technology Ventures, a division of Chevron U.S.A.

Solazyme is using a standard industrial fermentation process to produce its algal biodiesel. Wolfson believes the company’s proprietary process, based on proven methods that utilize the current infrastructure to refine and distribute the fuel, is the ticket to commercialization, which he sees as possible within the next two or three years.

Noting that the oil fields of Alaska’s North Slope likely are a product of an ancient massive algal bloom, he described his company’s process as “taking one of the best oil producers on the planet and marrying it with the tools of bioproduction and biotechnology to shrink that multimillion-year process into a few days.”

Arizona Public Service Company (APS) is taking a different tact. It has partnered with GreenFuel Technologies of Cambridge, Mass., to test the feasibility of recycling carbon dioxide emissions from its Redhawk gas-fired power plant. Using GreenFuel’s trademarked technology, smokestack emissions are trapped and transferred to containers holding algae, which consume carbon dioxide and multiply. Estimates are that for every acre of algae grown on the plant site, 150 tons of carbon dioxide can be absorbed — possibly 80 percent of the total emissions from the plant.

In addition, algae’s nontoxic leftovers have value, too: APS says the starches can be turned into ethanol and the proteins into livestock food.

APS was the first to use algae biomass produced on-site to create transportation-grade biofuels and received a Global Energy Award in 2006 for the accomplishment. However, early tests have not been without their problems. At Redhawk, the algae grew too fast, overwhelming GreenFuel’s ability to harvest the oil.

The company has come up with another approach and is looking to test the mighty alga’s ability to fight environmental crime at its Four Corners coal-fired plant. The company also is testing its technology at a 1,489-megawatt coal-fueled power plant in New Roads, La.

Imperium Renewables, a Seattle-based biofuels producer, is buying algal oil being produced by U.S. startup companies. Although commercial-scale production of an algae-derived diesel is likely years away, Imperium has dedicated its original 5 million-gallon refinery to research and development of algal biodiesel and other new fuels.