Fast-growing Trees Could Take Root as Future Energy Source
A tree that can reach 90 feet in six years and be
grown as a row crop on fallow farmland could represent a major replacement for
fossil fuels.
A tree that can reach 90 feet in six years and be grown as a row crop on fallow farmland could represent a major replacement for fossil fuels.
Purdue University researchers are using genetic tools in an effort to design trees that readily and inexpensively can yield the substances needed to produce alternative transportation fuel. The scientists are focused on a compound in cell walls called lignin that contributes to plants’ structural strength, but which hinders extraction of cellulose. Cellulose is the sugar-containing component needed to make the alternative fuel ethanol.
In 2005 ethanol accounted for only 4 billion gallons of the 140 billion gallons of U.S. transportation fuel used - less than 3 percent. About 13 percent of the nation’s corn crop was used for that production. Purdue scientists and experts at the U.S. departments of Agriculture and Energy say corn can only be part of the solution to the problem of replacing fossil fuel.
“If Indiana wants to support only corn-based ethanol production, we would have to import corn,” said Chapple, a biochemist. “What we need is a whole set of plants that are well-adapted to particular growing regions and have high levels of productivity for use in biofuel production.”
Using hybrid poplar and its relatives as the basis for biofuels has a number of advantages for the environment, farmers and the economy, they said.
“Poplar is a low-maintenance crop; plant it and wait seven years to harvest it,” Meilan said. “You’re not applying pesticides every year; you’re not trampling all over the site every year and compacting the soil. You’re allowing nutrients to recycle every year when the leaves fall and degrade. In addition, you are more likely to have greater wildlife diversity in poplar plantings than in agricultural fields.”
“We need a bioenergy crop that can grow many places year-round,” Meilan said. “The genus Populus includes about 30 species that grow across a wide climatic range from the subtropics in Florida to sub-alpine areas in Alaska, northern Canada and Europe.”
Researchers believe that using the hybrid poplar in its present form could produce about 70 gallons of fuel per ton of wood. Approximately 10 tons of poplar could be grown per acre annually, representing 700 gallons of ethanol. Corn currently produces about 4.5 tons per acre per year with a yield of about 400 gallons of ethanol. Changing the lignin composition could increase the annual yield to 1,000 gallons of ethanol per acre, according to experts. Planted on 110 million acres of unused farmland, this could replace 80 percent of the transportation fossil fuel consumed in the United States each year.
I’ve followed hybridization experiments with poplars for a couple of decades, now. It’s always been a wonder tree for fast-growing deciduous plantations.
These guys are proving what I always expected would be possible. Given appropriate economic circumstances, scientists would get the opportunity to run right past the know-nothings who want to stay with extractive, dead-end solutions.
Yes, I’m talking about long-term solutions. Think our politicians can handle that?
Posted: Thu - August 24, 2006 at 06:28 AM