The Seafarm project involves growing underwater algae farms on ropes. Photo:

The Seafarm project involves growing underwater algae farms on ropes. Photo:

William Tucker writes in about the lure the oceans have for advocates of biofuel, particularly in Scandinavia. “Two-thirds of the globe is covered with water,” says Khanh-Quang Tran, a Norwegian researcher who has published papers on the possibility of growing algae as a biofuel on an industrial basis. “If we used only a tiny portion of that space, we’d have enough to supply ourselves with all the fuel we needed.”

Of particular interest to researchers is one species, laminaria sacceyarina (“sugar kelp”), which grows along the coast of many countries, including Scandinavia. It is the seaweed that seems to be a flower but is actually all one undifferentiated cellular structure that takes on various forms in competing for sunlight. As the name implies, it contains lots of sugar – three times as much as the sugar beet. Scandinavian scientists have been especially intent on harvesting this plant for food and fuel use.

“It’s actually regarded as a nuisance, since it grows everywhere and clogs the beaches,” says Fredrik Grondahl, a researcher at the KTH Royal Institute of Technology in Sweden who heads the Seafarm project. “But it absorbs nitrogen out of the water, as effectively as a wastewater treatment plant. It’s regarded as an environmental problem, but it’s actually a valuable resource.”

The big question will be: Can a weed that grows so prolifically in the sea be domesticated so that it can grow in large quantities under controlled conditions?

Sweden and Norway seem to have taken the lead on this project, mainly because of their long coastlines, where the algae grow intensely in a cold climate. The Seafarm project involves growing underwater algae farms on ropes. The team collects excess algae from the Baltic Sea and cultivates it as food and fuel.

One technique is called the “sporophyte factory farm.” The algae spores are sown onto ropes. They sink and grow in the sea. In about six months they are harvested and processed on land. From there it can be converted to eco-friendly food, medicine, plastics and fuels such as methanol. The Swedish city of Trelleborg, with a population of about 30,000, estimates that 2.8 million liters of fuel can be extracted from its algae resources.

Kahnh-Quang Tran has been following another line of research and is now looking for partners who can help him move up to an industrial scale. He mixes a slurry of kelp biomass and water and heats it rapidly to 350 degrees Centigrade. Tran says the fast hydrothermal liquefaction gives him a product that is 79 percent bio-oil. “What we are trying to do is mimic the natural process that produces oil,” he said. “Whereas it takes geological time in nature to produce oil, we can do it in a matter of minutes.”