The Norwegian fjords are home to steep cliffs, blue water and, it turns out, teeming populations of a particularly slimy marine creature that could prove to be an interesting source of energy.
Yellowish tubes that feed on microorganisms, tunicates are the only animal known to produce cellulose. Cellulose breaks down into sugars that can produce bioethanol. Tunicate are also 60 percent protein when dried and a rich source of omega 3 fatty acids, making them a sought-after addition to salmon feed. They can produce 100 times more protein per 10 square feet than any land-based protein source.
Researchers at the University of Bergen decided to go ahead and test tunicates’ potential as a fuel source by farming them at a small scale. At the end of a finger-like fjord, they attached plastic sheets to the seabed and buoys. Tunicates attach to the resulting vertical sheets and feed on the microorganisms that flow by. They have no marine predators and grow year round, so their numbers rise quickly. About 2,500 to 10,000 of them can grow per 10 square feet.
“Our single greatest challenge is cultivating enough biomass per square metre to make operations profitable,” project manager Christofer Troedsson said in a statement. “We anticipate a crop of [220 to 440 pounds] per square metre, which is an extremely high yield. But that is what is needed for profitability because the price per [pound] is so low.”
They also have to develop more efficient techniques to remove water from the tunicates’ bodies after harvesting. The animals are 95 percent water. The researchers want to remove 90 to 95 percent of that water while still on the harvesting boat.
“On an isolated basis we have managed to mechanically press out 97 percent of the water,” Troedsson said. “Now we must try to carry out that process efficiently on board the harvesting boats, while at the same time pulling several tonnes of tunicates per hour out of the sea.”
They now plan to scale up quickly, with the project running through 2014.