PORTLAND, Ore. (AP)–“Pond scum” biodiesel? There are plenty of nicknames for algae, but it is one of the more plentiful natural crops in the world, and now it is being considered as a potential fuel source.
Oregon State University researchers are working to find an efficient method of processing algae to produce biodiesel fuel and ethanol.
Technology to mass-produce algae and extract its oils could be five to 10 years in the future, but the advantages would be worth the wait, says Ganti Murthy, an assistant professor of biological and ecological engineering.
“In a closed growing system,” Murthy said, “algae require 99 percent less water than any other crop.”
Algae can be found nearly everywhere, and it does not require a choice between food and fuel, such as converting corn into ethanol does.
“Algae can be grown using wastewater and in areas that cannot support agriculture,” Murthy said.
Varieties of the organism have been found flourishing in fresh and salt water and all kinds of environments, from the Arctic to tropical areas.
Algae also are highly productive compared with conventional crops. For example, a productivity model estimates that 48 gallons of biodiesel can be produced from an acre of soybeans. Algae could produce 819 gallons in a single acre, and theoretically as much as 5,000 gallons.
One of algae’s most remarkable qualities is that it can thrive on greenhouse gases from industry and coal-fired electrical generating plants. Waste carbon dioxide can be piped to algae ponds, where the gas is a necessary ingredient for growth and can even accelerate it by up to 30 percent.
Murthy has built two small experimental photobioreactors to grow microscopic algae in a closed system at OSU’s Sustainable Technologies Laboratory in Corvallis.
The reactors are simple plastic cylinders that have advantages over an open-pond system in greater productivity, reduced contamination and better control of growth.
It takes about three weeks for the algae, combined with light, water, carbon dioxide and mineral nutrients, to multiply and turn the water green.