By Ethan Goffman

Algae-based biofuels can power some cars with no modifications required.
© Congressman Brian Bilbray

It was big news last July when oil giant Exxon Mobil announced a $600 million deal with Synthetic Genomics, the company founded by science wunderkind J. Craig Venter, to explore using algae to create fuel. Adding Venter’s prowess at genetic modification to Exxon Mobil’s brawn seems to signify a new chapter in algal biofuels.

Bursting with lipids—fat, oily molecules—algae can be converted to a clean biodiesel or jet fuel. Algal biofuel could potentially fuel trucks, buses and many cars worldwide, with little change in infrastructure. The trick is to produce it cheaply enough, and on a large enough scale, for mass commercial use. Scientists are attempting to genetically modify algae to create the strains most amenable to farming and energy production.

Of the variety of biofuels being explored—from corn to sugar to cellulosic plants—“photosynthetic algae provide the best opportunity and have the biggest advantages,” says Rob Young, corporate spokesperson for Exxon Mobil. But, he adds: “We’re a long way from producing commercial-scale algal fuel.”

Exxon Mobil is the fourth major oil company to begin exploring algae’s uses, after British Petroleum, Conoco Philips and Chevron. The U.S. government is also jumping in, with the Department of Defense exploring the use of algae in jet fuels, and the Department of Energy working on a roadmap to spur algal biofuel use. One of its chief goals is to provide the same tax incentives for research and development of algal fuels as is available to other alternative energies.

When one considers the advantages of algal fuel, it’s a wonder it came so late to the alternative energy mix. The humble, one-celled organisms that compose algae are extremely efficient at converting sunlight to energy. Where corn ethanol produces about 250 gallons of fuel per acre per year and sugar cane produces 450 gallons, algae could yield more than 2,000 gallons.

 

Algae fuels discussed at a U.S. Navy event: Algae cells close (inset).
© Top: U.S. Navy, Inset: Solazyme

And algae thrive on carbon dioxide (CO2), which means that cultivation can function like a sink to reduce greenhouse gases. Some imagine algae cultivation around coal plants, sucking up CO2 before it can begin its deadly journey into the atmosphere.

Algae can also remove nitrogen and phosphorus from rivers and lakes, and convert agricultural runoff into “a much cleaner product,” says Darzins.

There is one drawback, however: The effects of mass cultivation of genetically modified strains of algae are unknown. Darzins wonders about the “environmental impact of growing a certain species of algae” over thousands of square acres where it may release into the wild.

Growing algae for biofuels also poses some thorny technical problems. Grown in open sunlight, all sorts of undesirable organisms can get into the mix. Enclosed bioreactors are far more expensive, and the algae produce waste in the form of oxygen, poisoning themselves. Without further breakthroughs, “ways of harvesting and extracting algae are too expensive,” says Darzins.

Still, Darzins is optimistic about the future. He foresees algal farms scaling up to a million square miles that can “start displacing 44 billion gallons of petroleum diesel” annually.

The company Solazyme’s algal biofuel production is achieved by using industrial wastes, sugar and wood chips to feed the algae. In this process, the algae take energy indirectly, from sunlight previously converted by other organisms. The algae start producing oil in a matter of days.

Overall, use of this biofuel “reduces greenhouse gas emissions by 85% compared to diesels from fossil oil,” says Solazyme President Harrison Dillon.

Solazyme is ready to ship oil by the barrel to interested parties who can then test it, although “we are not yet selling it commercially,” Dillon says. He believes his company is about “2½ years away from parity with $60- to $80-a-barrel oil.”

While the total economic and environmental effects of large-scale algal production are unclear, it seems likely that algae will come to play a growing part in the nation’s energy supply.