Exploring the Algae Tradeoff

UVa researchers look at energy yields, GHGs and the financial appeal of algae
| September 20, 2011

Lisa Colosi might be an assistant professor of civil and environmental engineering at the University of Virginia, but she knows what it is like to be a 1-acre farmer and an environmentally conscious driver. Colosi, along with a team of researchers at UVa, has completed a report that details whether algae-derived sources are more energy efficient and greenhouse gas (GHG) friendly compared to biofuels from switchgrass or canola. The purely hypothetical report based on engineering calculations and database impact factors indicates that although algae-based biofuel contains more energy per acre, the GHG levels are higher than other biofuels.

“We have this clear tradeoff,” Colosi says. “If I’m going to have a 1-acre farm and I wish to know what I should grow so that I can make biofuels to drive a certain distance in my car,” she adds, “I actually get the most, or the largest amount of usable transportation energy, if I grow algae.” Why? Because algae grow quicker and can be harvested multiple times a year. But, on the flip side, she says, if a person is concerned about their environmental impact incurred while driving, algae isn’t as favorable as other biofuels. Why? Because the more time a fuel is handled (heated up, stirred, upgraded) the more energy is used, she says, taking away from the overall energy efficiency related to that biofuel—an occurrence commonly associated with algae-based fuel.

“From our perspective, we are intrigued by the fact algae gives better overall energy yields, but we are puzzled by the fact that it doesn’t do as well on an environmental performance basis,” she says. But that isn’t all the team at UVa is intrigued by. “We are also interested to see how the energy analysis tracks with the financial analysis because there is very interesting decision-making when environmentally the right thing to do is A, and financially the right thing to do is B.”

Although Colosi and her team are still working to figure out the GHG impact shortfall of algae, the more important work may have nothing to do with GHGs but instead, money. Colosi says they are working to find out if current algae systems will be attractive enough “for people to make a living on,” and, if they aren’t, what policy or implements can be introduced to make sure they are. 

—Luke Geiver