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Engineers Concerned About Algae-Based Biofuel

DOE recently announced that it is awarding $78 million in stimulus money for research and development of algae-based biofuel. Yet researchers from the University of Virginia have found there are significant environmental hurdles to overcome, and propose using wastewater as a solution to some of these challenges.

The U.Va. research demonstrates that algae production consumes more energy, has higher greenhouse gas emissions, and uses more water than other biofuel sources - such as switchgrass, canola, and corn.

"Given what we know about algae production pilot projects over the past 10 to 15 years, we've found that algae's environmental footprint is larger than other terrestrial crops," said Andres Clarens, an assistant professor in U.Va.'s Civil and Environmental Engineering Department.

As an environmentally sustainable alternative to current algae production methods, the researchers propose placing algae production ponds behind wastewater treatment facilities to capture phosphorous and nitrogen – essential nutrients for growing algae that would otherwise need to be produced from petroleum. Those same nutrients are discharged to local waterways, damaging water bodies, and current technology to remove them is expensive.


Though the researchers found algae production to have a greater environmental impact than other sources, it remains an attractive source for energy. Algae - which are grown in water - don't compete with food crops grown on land and tend to have higher energy yields than sources like corn or switchgrass. Algae's high lipid content also allows for efficient refinement to liquid fuels that could be used to power vehicles.

"Before we make major investments in algae production, we should really know the environmental impact of this technology," Clarens said. "If we do decide to move forward with algae as a fuel source, it's important we understand the ways we can produce it with the least impact, and that's where combining production with wastewater treatment operations comes in."

To exemplify the importance of completing the environmental life cycle study, Clarens noted how the 2008 ethanol boom created a spike in corn prices worldwide, and raised complex issues that could have been avoided by producing separate crops for food and fuel.

"People were investing in ethanol refineries, but then we realized that it takes a lot of petroleum to grow corn and convert it to ethanol," Clarens said. "By the time you get done, you've used almost as much petroleum to make ethanol that you would have if you just put the oil straight into your car."

The research group plans to conduct demonstration projects for the wastewater production methods, and is pursuing complementary research on the economic lifecycle of algae compared to other bionenergy feedstocks.

(University of Virginia)