Energy and Environment Reporting for Texas

The Downside of Using Algae as a Biofuel

Photo by Mose Buchele

UT Research Engineer Robert Pearsal looks into a vat of algae.

It seems like everyone’s talking pond scum these days.

This year, people ranging from the President of the United States to this humble reporter, have spoken of algae’s potential in creating a carbon neutral biofuel. A recent study from the University of Texas showed how the tiny organisms could create 500 times more energy than they take to grow.  And the promise of the slimy green stuff is made even more enticing by the fact that it consumes carbon dioxide, sewage, and fertilizer run-off. It could, theoretically, clean the planet even as becomes a new source of fuel.

Now comes the downside.

A report by the National Academies of Science has identified major road blocks to the widespread development of algal biofuel. Chief among them is water use, says Paul Zimba Director for the Center of Coastal Studies at Texas A&M Corpus Christi.

Zimba took part in the study. He says “as much as 3000 liters of water” are required to produce a single liter of fuel when algae growers use open pond systems in arid environments.

“There are commercial operations, open pond system operations in the southwest primarily,” Zimba told StateImpact Texas. He says there’s a general feeling that water loss from those systems is too much “to allow the development of large scale systems hundreds of acres along this line.”

Water availability was just one of the challenges to widespread algae cultivation outlined in the report. Others include finding space for large growing operations, and competition for fertilizer.

“There will be a competitive demand for fertilizers that could affect food production in terms of being competitive cost-wise for their fertilizer products,” he said.  

Nonetheless, Zimba believes that algae holds promise as a fuel, and scientists are working on ways to avoid the pitfalls illustrated in the report.

They suggest or using sewage or agricultural runoff to cultivate algae. And when it comes to water, there’s a lot of research being done into saltwater or brackish water cultivation.


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