This IEEE Spectrum article investigates a plentiful, up-and-coming biodiesel source – algae. Using algae to produce biofuels instead of crops will help eliminate the competition between food and fuel. Also, rising food prices are breaking many people’s resistance to genetically engineered crops.
Algae – easy to grow and an efficient producer of biodiesel.
21 April 2008—Food riots erupting around the world have been partly blamed on the growing use of food products to produce fuels like biodiesel and corn ethanol. But biofuels need not come from food crops. According to some researchers, the best source of biofuel may be algae, best known as pesky green pond scum.
As anyone who has had to clean a swimming pool or fish tank knows, algae grow quickly. All they need is light, carbon dioxide, and a little water to grow like, well, weeds. It turns out that algae produce oil that can be processed to make biodiesel. In some species, this oil represents more than half of the plantlike organism’s mass. Researchers are also trying to genetically alter algae to make them give off copious amounts of hydrogen to meet the needs of future fuel-cell-powered cars.
Algae’s biodiesel capacity compares well with today’s sources, says Glen Kertz, president and CEO at Valcent Products, a Vancouver, B.C., start-up that aims to become a leading algae oil supplier. A single hectare planted with corn will yield about 40 liters of oil per year; a hectare planted with oil palm would yield 1000 L. But according to Kertz, an algae bioreactor occupying the same space could yield more than 48 000 L. “And we think we can do far better than that,” says Kertz. “In a few years, when we come to understand more about this crop we’re growing, we could see bioreactors producing more than [150 000 L per hectare per year].”
In addition to biofuel, algae can also produce hydrogen, which can then power fuel cells, another clean source of electricity.
Meanwhile, other researchers are trying to ratchet up algae’s natural production of hydrogen to make pond scum bioreactors a fuel source for fuel cells. David Tiede, a senior scientist at Argonne, says he and his colleagues are looking to manipulate an enzyme called hydrogenase, which generates small amounts of hydrogen gas during a process that is concurrent with photosynthesis. Tiede hopes to take the part of the hydrogenase enzyme that produces hydrogen and insert it into a protein integral to photosynthesis. Doing so, he says, could yield amounts of hydrogen equivalent to as much as 10 percent of the algae’s mass, or roughly the same as the amount of oxygen they create.
Algae’s fecundity is so great that researchers at the DOE’s National Renewable Energy Laboratory say that algae bioreactors covering less than 40 000 square kilometers—roughly one-tenth of the sun-baked state of New Mexico—could churn out enough biodiesel, bioethanol, and molecular hydrogen to completely replace petroleum as transportation fuel in the United States, the world’s largest automotive market. That’s a lot of pond scum, considering that in 2006, U.S drivers burned through more than 800 billion L of fuel, according to the Energy Information Administration, which is part of the DOE.
Algae awareness! Algae is the Earth’s primary oxygen source.
But biofuel experts foresee a day when algae bioreactors like Valcent’s will be set up not only in places like New Mexico’s deserts but also in urban areas, atop the smokestacks of industrial plants or coal-burning electric generation plants, and in rural areas where the algae would act as remediators, using human or animal waste streams as a food source. “The reality is that from an ecological standpoint, algae already play a huge role because they’re the primary oxygen source for the planet,” says Kertz. “Most people don’t know that. But I think it’s time for some algae awareness.”
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Also from IEEE, researchers are trying to use termites to produce ethanol.
