By Audrey Rabalais, CG Science

In the perpetual quest for more efficient and renewable sources of energy, Dr. Ben Stuart, director of the Biofuels Research Laboratory at Ohio University, is turning his focus away from amber waves of grain for emerald ponds of algae.

Stuart and other researchers are cultivating and processing cyanobacteria, or blue-green algae, that can be harvested and processed by different methods to produce gasoline and diesel fuel.

“What I end up with is a chemically equivalent fuel that is made from biomass that’s currently being produced,” Stuart said. “So it’s domestically produced, it’s renewable, which means it’s sustainable, the only question is ‘how much total biomass do I need?’”

The diesel fuel produced from algae acts in the same way as the petroleum-derived diesel fuel. Algae can produce 3,000 to 5,000 gallons of oil an acre per year, according to the National Renewable Energy Laboratory. In order to keep enough diesel fuel in all U.S. engines for a year, the landmass required to grow that amount of algae would be the equivalent of one-third of Ohio.

Comparing these figures for algae with other sources of biodiesel has created many algae believers.

For every acre of corn, 18 gallons of oil are produced in a year. To provide enough diesel fuel for the United States for one year, farmers would have to grow 3.5 billion acres of corn, the equivalent of 122 times the landmass in Ohio.

The figures for soybeans are slightly less. For every acre of soybeans, 50 gallons of oil are produced in a year. The landmass required to fuel the United States for one year is the equivalent of 46 times the landmass in Ohio.

Biofuels became popular when scientists began searching for a way to reduce greenhouse gas emissions and produce a more renewable, ecological-friendly source of fuel. Utilizing algae as a fuel source accomplishes both.

So how do algae translate into a fuel source?

One method is to directly extract oil that is contained in the algae. By mixing the algae with solvents such as alcohol, the cell membrane is broken and the oil inside the cell can be extracted to be used as an alternative to diesel fuel.

The oil, however, only comprises about 20 percent of the organism, Stuart said.

A video about the algae purification process (produced by the Scripps School of Journalism).

Another method is gasification, which uses 60-70 percent of the organism. In this process, biomass is burned in a reactor with little oxygen. Rather than the normal oxidation products of carbon dioxide and water, it releases carbon monoxide and hydrogen. These products are then sent through another reactor where the carbon monoxide and hydrogen are recombined to form CH₂, the building block for alkynes. These hydrocarbons are put into chains to form petroleum products that can then be refined and used as anything from jet fuel to low-grade diesel fuel.

In 2008, biomass accounted for about four percent of the energy consumed in the United States, but making biofuels a greater part of the U.S.’s energy scheme may be a smoother transition than one would think. Stuart points out that the same infrastructure and technology that is being used for coal can be used for biomass. The two could even be burned concurrently, reducing the use of fossil fuels.

But, there are some downsides to biomass energy.

“Biomass has a little bit more ash component to it, so you don’t get as much energy out of it. With a good coal, 90 percent of it is right into the fuel. Even a bad coal is at 80 percent. With biomass it’s 60 to 70 percent” Stuart said. “So, yeah, I’m not as efficient, but I’m still pretty close and it’s a lot better than the 20 percent that I would have gotten through biodiesel by oil. For me, it’s an acceptable percentage loss because of its renewability.”

Stuart suggests that, much like diversifying a stock portfolio, the best plan for energy conservation is to dip into several sources at once. This will spread the burden of powering the U.S. over a wide range of options rather than quickly depleting one or two.

The change to alternative energy sources will not occur over night. A pond one-third the size of Ohio is a big pond and cannot be created in one day, Stuart said.

“You have to start somewhere. So you start building that infrastructure. Ten years? No. Twenty years? That’s a start. Fifty years? Now you’re thinking right,” Stuart said. “Our petroleum infrastructure took 150 years to build or more. It doesn’t go away in one or two years. But as it ages, you can opt to put in new infrastructure to make a step away from it.”

The next time you pass a pond with a bright green blanket of algae resting on top of it, reconsider the worth. In fifty years, algae could be the most powerful plant in the world, fueling everything from fighter jets to minivans, curbing global climate change and reducing humans’ ecological footprint in the process.