voyager

Q&A December 2008

Q Where did you get the idea to use algae as biofuel?
—Submitted by 5th graders at Hearst Elementary School, San Diego, Calif.

A Some algae make abundant amounts of molecules called lipids (a form of fat) that can be converted into liquid fuel for car engines. The use of lipids for fuel has a long history, and the earliest fuel sources came from plant oils. For example, one of the first diesel engines ran on peanut oil in 1900.

flasks Flasks of green algae used in biofuel experiments at Scripps Oceanography.


In general, lipids aren't perfect for fuel, but if you chemically alter their structure, they become combustible like oil and can power a car engine.

In nature, algae produce abundant amounts of lipids, which they store as a form of chemical energy that can be used when nutrients are low and to remain buoyant in the ocean. Buoyancy helps algae stay near the ocean surface, where they capture energy from the sun and use it to convert carbon dioxide into sugar. This process is called photosynthesis. Then, sugars are broken down into smaller carbon units and reassembled to form lipids.

Carbon Capture Corporation develops algae ponds in Imperial Valley, Calif.

In 1978, the U.S. Department of Energy began investigating algae as a source of lipids for biofuel. Algae were chosen because they grow in much greater abundance and much more rapidly than plants. They also can produce tens to hundreds of times more lipids in the same area as plants. Algae can grow in salty water and in regions where the soil is not suitable for growing crops. Algal-based biofuels offer the possibility of a renewable source of energy that is nearly "carbon neutral," meaning that the amount of carbon dioxide produced by engines that run on the biofuel is partly compensated by the amount of carbon dioxide captured from the atmosphere when the algae create the lipids.

It's a win-win!

— Mark Hildebrand, biologist, Marine Biology Research Division

 To learn more about how algae can make fuel, read our feature "Green Bullet."
 

voyager

Scripps Scientists take on questions from students curious about ocean and earth sciences


hildebrand

"One of the first diesel engines ran on peanut oil in 1900. "
—Mark Hildebrand, biologist, Marine Biology Research Division