Tuesday, April 25, 2006

Biodiesel and cleaner air from algae

Extracts from
Algae - like a breath mint for smokestacks

By Mark Clayton for The Christian Science Monitor

BOSTON – Isaac Berzin is a big fan of algae. The tiny, single-celled plant, he says, could transform the world's energy needs and cut global warming.

... Dr. Berzin, a rocket scientist at Massachusetts Institute of Technology ... came up with the idea for using [algae] to clean up power-plant exhaust.

Bolted onto the exhaust stacks of a brick-and-glass 20-megawatt power plant behind MIT's campus are rows of fat, clear tubes, each with green algae soup simmering inside.

Fed a generous helping of CO2-laden emissions, courtesy of the power plant's exhaust stack, the algae grow quickly even in the wan rays of a New England sun. The cleansed exhaust bubbles skyward, but with 40 percent less CO2 (a larger cut than the Kyoto treaty mandates) and another bonus: 86 percent less nitrous oxide.

After the CO2 is soaked up like a sponge, the algae is harvested daily. From that harvest, a combustible vegetable oil is squeezed out: biodiesel for automobiles. Berzin hands a visitor two vials - one with algal biodiesel, a clear, slightly yellowish liquid, the other with the dried green flakes that remained. Even that dried remnant can be further reprocessed to create ethanol, also used for transportation.

GreenFuel has already garnered $11 million in venture capital funding and is conducting a field trial at a 1,000 megawatt power plant owned by a major southwestern power company. Next year, GreenFuel expects two to seven more such demo projects scaling up to a full production system by 2009.

One key is selecting an algae with a high oil density - about 50 percent of its weight. Because this kind of algae also grows so fast, it can produce 15,000 gallons of biodiesel per acre. Just 60 gallons are produced from soybeans, which along with corn are the major biodiesel crops today.

Berzin calculates that just one 1,000 megawatt power plant using his system could produce more than 40 million gallons of biodiesel and 50 million gallons of ethanol a year. That would require a 2,000-acre "farm" of algae-filled tubes near the power plant. There are nearly 1,000 power plants nationwide with enough space nearby for a few hundred to a few thousand acres to grow algae and make a good profit, he says.

In 1990, Sheehan's NREL program calculated that just 15,000 square miles of desert (the Sonoran desert in California and Arizona is more than eight times that size) could grow enough algae to replace nearly all of the nation's current diesel requirements.

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