The Power of Pond Scum: Biodiesel and Hydrogen From Algae

A start-up may have the key to boosting algae's chances as a future fuel, and scientists see a path to hydrogen production from pond scum
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].”

Valcent’s proprietary technique, called Vertigro (which the company is also applying to the cultivation of plants like lettuce), is one of a bunch of approaches to growing algae. Instead of growing pond scum in large open ponds —whose yields are affected by seasonal variations like air temperature and relative humidity—Valcent uses the area above a plot of land to increase its yield. Hence the name Vertigro.

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