Algae: Hope or Hype?

Algae has been called the "fuel source of the future." But when that future will come is still hard to call.

Roger Ruan

For more on Roger Ruan's novel approach to biofuel production, read "From the Sewage Plant, the Promise of Biofuel" at Yale Environment 360.

Talk about making lemonade out of lemons. University of Minnesota scientist Roger Ruan and his colleagues are busy figuring out how to produce biofuel from the stinky stuff of sewage treatment plants.

No, not that stuff. The algae that can grow in it. There are hundreds of thousands of types of algae, and scientists have found some that contain up to 75 percent oil. The trick is to produce fast-growing, oil-rich algae from the wastewater, harvest it, extract the oil and convert it to fuel.

The process involves drying and pressing the algae before adding a solvent to extract the oil, not unlike a method used for soybeans. Ruan says the equivalent of 15,000 gallons of oil could grow annually in an acre of algae, as opposed to 20 gallons of oil from an acre of corn.

Last February, Ruan’s pilot project was the headline of the month in newspapers across the country, only to take a back seat to other “Next Big Things” a few months later. So, is algae really the fuel source of the future? Or will it go the way of other highly hyped but still unproven gasoline substitutes, such as hydrogen?

Like any new technology, Ruan says, the idea is not without its hurdles. “There is a general consensus that there’s great potential here, but the key is cost.”

A national boom in interest from venture capitalists, the Pentagon, utilities and oil companies has corresponded with more media attention to the industry, not coincidentally while gas prices skyrocket.

But at a current cost of about $20 per gallon of algae biofuel, you won’t be filling up your Ford Focus with pond scum byproducts anytime soon.

Moreover, in order to keep up a steady cash flow, individual companies need to sell other high-value components from the same stock, says Clemson University professor David Brune, who has worked with algae for 20 years.

“There is no simple answer,” says Brune. “You are not just making one product. Biorefineries need to make many products. The bottom line is, how well can you use all the materials?”

As one revenue-producing measure, Ruan’s team is looking at the potential of using leftover biomass to produce bio-oils and other products such as protein-rich animal feed.

Along with creating new economic opportunities for the state, the Metropolitan Council, Xcel Energy and the U of M’s Initiative for Renewable Energy and the Environment are supporting the project with an even bigger-picture goal in mind. Currently, the wastewater solids incinerators at two local treatment plants release carbon dioxide into the atmosphere. These emissions could be captured, while simultaneously enhancing the algal growth.

From New Mexico to New Zealand, growing algae in large, open ponds is a widespread practice in warmer climates. However, “that wouldn’t work so well in Minnesota in February,” says IREE Director Dick Hemmingsen. In addition, open ponds are prone to evaporation and are vulnerable to contamination by bacteria or invasive species.

Ruan’s team has responded by growing the algae indoors, in a closed-loop system located at a Mississippi River treatment plant near St. Paul. The system utilizes the wastewater and heat produced by the treatment plant.

Yet, one major hurdle remains, says Michael Briggs, a lab manager in the University of New Hampshire’s Biodiesel Group: We need 9.5 million acres of algae farms to grow enough biofuel to replace our current oil consumption. That’s an area about the size of Maryland.

 “They never talk about the big problem, which is the big scale,” says Brune. “If they did, funding agencies would run for the hills.”

Despite the complexities, Hemmingsen believes that algae will have staying power for several reasons, and our basic needs are high on the list. “The potential yields don’t compete with tortillas or cornflakes, so it gets us out of the food-fiber-fuel debate.”

In what might be the perfect storm of alternative fuel ideas, at least one company is attempting to extract hydrogen from algae.

At any rate, algae holds promise. But if it doesn’t work out, perhaps lemons are next.

MARK NEUZIL is a professor in the Department of Communication and Journalism at the University of St. Thomas, St. Paul. He is a regular contributor to and the author of five books, including The Environment and the Press: From Adventure Writing to Advocacy (Northwestern University Press, 2008).