Could algae be the next great biofuel source?

Published: November 14, 2018

green-algae-with-large-cells Photo by Ye.Maltsev/Shutterstock

It isn’t often we see algae in a positive light—it is the bane of lakefront property owners and can spell a summer without swimming or fishing if blooms get out of control. But researchers at the University of Michigan have plans to put this living organism to use. They’re working on preparing the perfect cocktail of algae to run a diesel combustion engine.

Creating a biofuel from algae is not a new idea, says André Boehman, a professor of mechanical engineering at University of Michigan and director of its automotive lab.

“Lots of people have tried to do this,” he says. “A lot focused on highly engineered algae—a monoculture that has problems of scale-up … To make fuel, you have to see a cost-effective way to scale up.”

There are a few steps to the three-year project Boehman and his team are undertaking, thanks to a $2-million grant from the U.S. Department of Energy. The first step falls under the direction of U of M biology professor and Director of the Institute for Great Lakes Research, Bradley Cardinal.

His team is growing different combinations of algae in large kettledrums to figure out which species are best suited for a fuel source. “What are the right combinations to maximize lipid yield, overall productivity, and to keep the algae from crashing,” says Boehman.

The lipids, or oils, are the portions that are traditionally extracted from algae to develop biofuel—as with soy or canola biofuel. For this project, the team that also includes scientists from Penn State, would take the entire algal paste out of the tub and process it through hydrothermal liquefaction—emerging technology using pressure and temperature, modelled after the natural process of oil production underground—to make the biocrude, explains Boehman. “The whole wet mess, skimmed off the pond, that whole mass is processed altogether. Lipids but also algae mass which can then yield more fuel,” says Boehman.

With that biocrude product, Boehman’s team will work on refining the recipe of algae used according to how it works within the combustion process. “We want to understand the bio-blend stock’s behaviour, optimize that and make certain improvements with diesel combustion and the quality of fuel,” he says.

The payoff for this project could be huge, says Boehman. A current environmental target calls for 36 billion gallons of transportation fuels in the U.S. to be made from blended sources—or biofuel—by 2022. “When you grow soybeans in a large part of the U.S. to make biodiesel, you get, with modern cultivation technology, something in the order of 90 gallons per acre—maybe that has crept up in the last several years,” says Boehman. “Our projection is you could grow algae at 3,000 to 5,000 gallons per acre.” And this doesn’t require the use of good farmland that could otherwise grow food crops.

Boehman says they expect to have at least 60 per cent renewable content in the biodiesel produced through this process—similar to other biofuels—but it could also be higher. And there’s potential for using captured CO2 to feed the algae and increase productivity. “There’s very good potential,” says Boehman. And this could do wonders for cleaning up algae’s otherwise murky reputation.

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