Green Energy From Forests
If a tree falls in the forest and no one is there, could it make biofuel? NC State scientists are determined to answer this Zen-like question with a less philosophical “yes.” The University is taking a vertically integrated approach to research on using cellulose in trees to make fuel, from harvesting the wood to processing ethanol to converting aging paper mills into biofuel refineries.
“Making ethanol out of biomass isn’t just about making money—it’s about national security.”
Forestry professor Joe Roise didn’t set out to be a biofuel feedstock collector. He was only trying to decrease the risk posed to suburbs by wildfires. Decades of wildfire suppression have left forests brimming with enough small trees to create a safety hazard if they go up in flames, he says. With funding from the U.S. Forest Service, Roise’s research team worked with a mulching machine manufacturer to design a harvester that could drive through a forest, collect small woody material, grind it up, and dump it in a bin to be hauled away.
The researchers have been providing the chips to a wood-fired power plant in Craven County, but Roise says someone could easily process the material for ethanol if the economics are right. “Biomass is everywhere in the forests,” he says. “The stuff we’re after isn’t on anyone’s radar, and it can minimize the wildfire danger, improve forest ecosystems, and give us an energy source that doesn’t cut into our food or timber resources.”
Making ethanol production more cost-effective is
Dr. Hasan Jameel’s goal. One-third of the production cost is tied up in pretreatments to separate cellulose from lignin, the glue-like polymer that makes wood stiff. The pretreatments leave a chemical mess behind, so Jameel, a professor of wood and paper science in the College of Natural Resources, has devised an alternative, water-based separation process. He and Dr. Vincent Chiang, co-director of the Forest Biotechnology Group, have won grants from the U.S. Department of Agriculture and the Department of Energy to bioengineer and study the feasibility of growing genetically modified trees in North Carolina and using them to produce ethanol inexpensively. The poplars have a low lignin content, and the water in Jameel’s high-temperature process dissolves the hemicellulose in the wood, poking holes in the polymer structure so enzymes can get around the lignin and break down the cellulose for processing.
To cut production costs even further, Jameel and Richard Phillips, a former International Paper executive now working in the Department of Wood and Paper Science, have calculated the economics of converting paper mills to ethanol production plants. Building a plant from scratch to produce
100 million gallons a year could cost $500 million, while converting a paper mill could cut that in half, Jameel says. NC State is part of a team that is trying to produce six million gallons of biofuel a year at a Wisconsin paper mill under a recent Department of Energy award. “These are not mom-and-pop operations,” Jameel says. “Making ethanol out of biomass isn’t just about making money—it’s also about national security.”