Powered by pond scum

Algae may prove a promising source of biofuel

  • Jim Sears imagines tank after tank of algae surrounding rural coal-fired power plants, as in the artists rendering above

  • Sears examines algae samples at his Fort Collins lab


FORT COLLINS, COLORADO -- At the start of his career in 1974, Jim Sears was a long-haired hippie who went straight to work developing diving equipment for the Navy Seals. “Nothing worse will ever happen to you in nature,” the jovial, silver-haired inventor from Boulder, Colo., now says with a belly laugh. “They tried to drown me 99 different ways.”

Sears spent years inventing new equipment, including an underwater speech unscrambler and a hand-held mine detector. During that time, he says, he learned a lot about water and aquaculture. But one particular vision — of glowing phosphorescent algae seen on a night dive off Panama City, Fla. — would change his life.

Decades later, as Sears pondered global warming and diminishing oil in his Colorado garage/office/science lab, he remembered the tiny daggers of light that had swirled past his face mask. He started contemplating the energy potential of algae. His research led him to a National Renewable Energy Laboratory report detailing 18 years of algae-to-biodiesel research.

Today, Sears is one of a handful of sustainable energy entrepreneurs and researchers, from M.I.T. to Colorado State, who say algae might be the next answer to oil. They’re picking up where the National Renewable Energy Laboratory left off when it abandoned algae-to-biodiesel research in 1996. (Cheap oil and Department of Energy budget cuts killed the program.)

If you pick the right algae, place it well and grow it using an efficient reactor, an acre yields about 10,000 gallons of biodiesel per year. That compares to a mere 50 gallons from an acre of soy. Adding to the enticement, lipid-rich species of algae require a concentrated source of CO2 that can be gleaned from heavy emitters like breweries and power plants.

Imagine miles of algae farms surrounding rural coal-fired power plants, sucking up Earth-warming CO2 straight from the stack. Picture them in places like Colorado, New Mexico, Arizona and Nevada. Algae farms need warm, sunny, flat land with a low population density and a slew of CO2-emitters. That means, researchers say, that the Southwest has the potential to be America’s new green belt — for algae farms, that is.

Algae requires far less fertilizer than soy or corn. Unlike corn, which recently hit record-breaking prices due to competition for ethanol plant feedstock, it doesn’t create a food-versus-fuel conflict. Algae farms can use agriculturally undesirable land. And with Sears’ technology, algae uses less than one percent of the water it takes per acre to grow soy.

“This is the future — somehow,” Sears says.

The National Renewable Energy Lab had been growing algae in open ponds in Roswell, N.M., a scheme that strategic energy analyst John Sheehan says worked OK for small-scale research, but not as a perpetual and consistent source of algae. Open ponds invited invasive algae, evaporation and too many environmental variables. Sears figured the only way that algae would ever reach its potential would be through closed bio-reactor systems.

Sears designed a model bio-reactor that he calls Mercury One. It’s basically a giant waterbed, consisting of two 70-foot-long, 4-foot-wide plastic bags filled with a foot of nutrient-rich water and algae, and a thermal blanket to regulate temperature. Once the algae grows dense enough, it’s removed from the reactor to process into biodiesel. After the algae is removed from the reactor, it is spun dry and separated into lipids (fats), carbohydrates, protein and other components. The lipids are brewed into biodiesel through the same kind of chemical separation process used for soybean oil or french-fry grease. As a bonus, leftover carbohydrates from the algae can be fermented for bioethanol, and the protein can be fed to livestock. This reactor is still at one-fifth scale; at full scale, Sears envisions a viable fuels system that is cheap enough to use in places like India, China and sub-Saharan Africa.

Sears’ company, Solix Biofuels, has found a home in an abandoned Fort Collins power plant along the banks of the Cache La Poudre River. Here, he’s joined forces with Bryan Willson of Colorado State Univer-sity’s Engines & Energy Conserva-tion Lab. Willson, Sears and a team of designers are still tweaking the bio-reactor technology. Sometime next year, they will build their first full-scale reactors on the east side of Fort Collins’ New Belgium Brewery — CO2 emissions from beer fermentation will fuel the algae. Solix’s petite Ukrainian chief biologist, Anna Ettinger, is helping the company hone in on the right species of high-lipid pond scum.

Despite promising lab results from around the country, not everyone is sold on the technology. Biofuels skeptic Tad Patzek, professor of civil and environmental engineering at the University of California, Berkeley, says algae is undoubtedly efficient, but computer modeling makes him doubt that any plant-based system can significantly slake the world’s growing thirst for energy. He’s still working on a mathematical analysis, but he doesn’t hesitate to point out the hurdles: diseases that plague concentrated marine life, constraints on desert water supplies, land-use controversies and the challenges of sustaining massive-scale outdoor operations (easily 15 to 20 square miles of algae reactors around a 1,000 megawatt plant).

In Colorado, Xcel Energy, which produces about 3,000 megawatts of coal-fired power for the state, says it’s always interested in ways to cut carbon emissions, but a project like Solix’s algae reactors is probably a long way out. Xcel tends to own a few acres, not several square miles, around its power plants. If a CO2-capturing algae farm were to be built near any of its rural plants, the land would have to be bought or leased from nearby ranchers.

Despite the promise of algae farming, everyone from environmentalists to bankers will have to weigh in before great green fields of algae spread across the Southwest.

“It’s a noble task,” says Ettinger as she swirls a beaker full of pale green algae. Having lived through the 1986 meltdown at the Chernobyl nuclear power plant, she sees great hope in the future of clean algae fuel. Last year, she turned down three jobs with plush offices, stunning mountain views and more money to join Solix. “You come here to do something good for this world,” she says.


The author writes from Steamboat Springs, Colorado.

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