Plant waste biofuels benefit from food debate
By Julie Gordon
TORONTO (Reuters) - In the search for renewable energy, turning low-value materials like switchgrass and corn husks into ethanol to fuel cars is something of a Holy Grail.
In theory, these materials would replace corn as the main feedstock for ethanol in North America, reducing the pressure on farmland that has played a role in rising food prices and put drivers into competition with hungry people.
But scientists on the front lines of this search are finding that making the process commercially and environmentally viable is proving much harder than some of the hype would suggest.
In a greenhouse on the top floor of the science complex at the University of Guelph in southwestern Ontario, microbiologist Anthony Clarke stands next to rows of corn plants sprouting out of black plastic pots.
In them, he sees the future of renewable fuel -- but he's not looking at the corn kernel.
"We have all that other green matter: the leaves, the stalk, the husks even," he said. "So the idea would be to use that material for the biofuel and the grain itself as a food."
But turning plant waste into fuel is not easy. Plant cellulose is woven into a tight grid, making it difficult -- and costly -- to extract the glucose needed to make ethanol.
"There is a technology out there for biofuels from cellulosic material, but it does involve acid and steam," said Clarke. "Both require energy to produce. So more energy is going in, currently, and expense, then is being recovered." Continued...