Seaweed – it’s great for sushi, and perhaps even better for biofuels.
A study by a University of Victoria mechanical engineering student has shown that large-scale seaweed farms could make environmental sense in B.C. in terms of producing biofuels.
Aaron Philippsen, a 27-year-old Saanich resident, produced a study for his master’s thesis that shows B.C. has the coastline capacity to produce enough seaweed-based ethanol to replace what’s being imported into the province. And on the face of it, that ethanol production would produce less greenhouse gases than conventional ethanol derived from corn or wheat.
“With seaweed, you don’t need irrigation, you don’t need farmland. These are the main drawbacks to current biofuels,” Philippsen said. “We found seaweed ethanol is twice as effective in terms of reducing greenhouse gas emissions.”
Philippsen’s work estimated B.C.’s near-shore coastline could yield 1.3 billion litres of ethanol, where B.C. consumes about 240 million litres of ethanol, typically blended with gasoline. Seaweed-based animal feedstock could also offset costs for large-scale seaweed ethanol production.
“It looks like there’s potential to reduce the amount of ethanol imported into B.C. through farming on the coast,” he said. “Here it could make a significant difference. Globally, it won’t replace gas.”
The study examined the “energy return” and carbon output for seaweed versus conventional biofuels in terms of equipment, harvesting, processing, transportation fuel and electrical consumption. The biggest factor behind why seaweed is less of a carbon emitter than corn or wheat is the use of fertilizers.
“Growing seaweed doesn’t require fertilizer,” he said, although it does require large rafts in the ocean, which would need to co-exist with fishing, boating and other aquaculture.
Slightly more ethanol can be squeezed from corn than seaweed, and large-scale seaweed production needs a renewable energy process for drying, otherwise it’s unlikely to be cost effective or have a large advantage in terms of carbon output.
“Seaweed is big and heavy and has a lot of water to deal with,” he said. “That means you have to use solar thermal (greenhouses) or geothermal to do the drying. Part of the next step is to look at the cost of thermal drying in our climate.”