V i v i a n  S o n g
Freelance writer
Freelance writer
Pond scum takes new meaning

Published in the Toronto Sun and Sun Media papers July, 2008.

Pond scum.

It's a harsh spiteful slur I reserve for those who have wronged me injuriously: That stupid bird that pooped on my skirt recently, narrowly missing my head, the driver of the beige sedan who nearly ran me over on my bike last month.

But I may soon have to find another slanderous, acid barb because in the renewable energy world, the scum of ponds is being hailed as the latest, great answer to the global oil crisis and climate warming. Sadly, the epithet loses some of its venom when it's upheld as honourable goop.

As a biofuel, algae doesn't present a moral dilemma since it's not a food crop and doesn't require arable land to grow. The single-celled organisms are fiendish reproducers, able to double in biomass in a matter of hours in contrast to traditional crops such as soybean and corn. Not only can the lipids or fats be turned into biodiesel and biofuel, but algae ponds also soak up carbon dioxide, common industrial pollutants like nitrogen dioxide and absorb nitrogen from wastewater.

They need just carbon, sunlight and water to survive. They don't need freshwater, able to live happily on dirty water or saltwater. Some strains of algae can yield more oil per acre than any other terrestrial feedstock. For example, some algal species contain as much as 50% of their weight in oil, estimated to be between 30 to 100 times more productive than land crops. Lab tests indicate algae can produce up to 19,000 litres (5,000 U.S. gallons) of oil per acre per year. That compares to 190 litres (50 gallons) of oil per acre per year from soy, 110 litres (30 gallons) from corn, and 2,500 litres (650 gallons) from palm.

The U.S. Department of Energy also estimates that replacing all the petroleum fuel in that country with algae fuel would require 40,000 sq/km of land -- less than one-seventh of the area devoted to growing corn in the United States, or roughly the size of Maryland.

In Canada, a group of four research partners are working to harness the power of algae with the help of government funding. Scientists at Innoventures Canada, or I-CAN, an umbrella organization for provincial research organizations, have been working on the CARS program -- Carbon Algae Recycling System. The project proposes to divert flue gases such as carbon and nitrogen dioxide from industrial facilities such as power plants and feed them to algae ponds to stimulate growth. Preliminary test results have shown that a 32-sq/km algae pond will sequester up to 30% of the greenhouse gases produced by a 300 MW coal-fired power plant. Algae would then be harvested and processed into biodiesel, biofuel, ethanol and the remaining biomass turned into animal feed. The system is described as simply "fast-tracking" Mother Nature's own respiration process.

"That's what so exciting about this," said project manager Quinn Goretzky at the Alberta Research Council, one of the provincial partners. "It's a natural system."

Previously, it was believed Canada's feeble light conditions and extreme weather wouldn't support algae systems, Goretzky said. But Canadian researchers are looking at the potential of a hybrid covered pond system -- a contained system that avoids the dangers of invasive species taking over the algal strain in an open pond.

"The uniqueness of the CARS system is that we don't want to create a major footprint on space," he added. That means researchers are trying to increase efficiency by increasing the depth of algae ponds. Typically, a pond is 30 cm deep and the light penetrates 20 cm off the top. CARS scientists want to triple the depth to 90 cm.

The project's Quebec partner, meanwhile, is working on growing Canadian algal species in the right conditions. But Le Centre de Recherche Industrielle du Quebec is also looking at other pharmaceutical byproducts algae can yield, like pigments and cancer-fighting properties, part of the project's goal to make the system "pay for itself" with value-added products. Currently, costs make algae biofuel prohibitive.

"There's a vast range of products that we can extract from algae," said spokesman Laurent Cote.

Currently researchers are exploring three main ways to extract oil. Adding solvents to the system, heating the algae and using ultrasounds, a new technique that promises to be economically viable, Cote said. The most optimistic estimate would see algae biofuel enter the consumer market in about five years, he added.

While enthusiasm for algae's potential is high, sceptics point out stored carbon will eventually be returned to the atmosphere when it's burned. But because algal biofuel replaces petroleum fuel, we're reducing our dependency on fossil fuels and therefore reducing our net emissions.

"We see this as a tool in a toolkit in minimizing emissions," Goretzky said. "There is no one solution."

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