Recent movements urging consumers to reduce the country's dependence on oil by using an ethanol-gasoline combination to power their vehicles may be strengthened by a new process invented at Dartmouth. In response to the high costs of producing ethanol, which is made from corn and other grain products, current Thayer professor Lee Lynd and former Thayer researcher Y.H Percival Zhang have developed a new, cost-effective ethanol pretreatment process that could eventually help the United States break its dependence on foreign oil.
"We have the technical ability, but making ethanol production economical is the problem," said Zhang, currently an assistant professor at the Virginia Polytechnic Institute. "The largest challenge for bioconversion from raw materials to bioethanol is high processing costs, resulting in higher prices for bioethanol than for gasoline."
In his most recent State of the Union address, President George W. Bush called for a doubling in ethanol production by 2012 and said he aimed to replace 75 percent of U.S. consumption of Middle-Eastern oil with bioethenol by 2025. In order to reach this goal the United States must increase its ethanol production to 30 to 60 billion gallons per year, Zhang said, which would also mean using the entire corn plant including the leaves, stalks and cobs.
Leftover stalks of grain and corn, which can be processed into ethanol, are the most abundant agricultural residues in the United States. In order to utilize these resources, the sugars must be separated from the plant cell wall through an expensive process.
"No one wants to take the risk --- to invest a billion dollars in a large-size biorefinery based on lignocellulose [which is present in woody plant cells]," Zhang said. "Processing costs are also high. It requires chemicals, utilities, enzymes and recycling in the pretreatment and the sequential processing stages."
But Zhang and Lynd hope to change this by introducing their new technology, which makes the entire corn plant usable, into the mainstream of ethanol production methods.
The researchers' cost-effective pretreatment process operates at much lower temperatures than other methods, 120 degrees instead of 150 to 250 degrees. In addition, their process uses a strong cellulose solvent instead of highly corrosive chemicals and high pressure to break cellular bonds.
Unlike other methods, their process also results in four profitable biproducts: lignin, hemicellulose sugars, amorphous cellulose and acetic acid.
"Co-products can generate more income, making biorefinery more profitable, and enable satellite biorefineries that fully utilize scattered lignocellulose resources," Zhang said. "For instance, lignin has many industrial uses, from glue to polymer substitutes and carbon fiber, and xylose can be converted to a healthy sweetening additive."
If Lynd and Zhang's process does eventually enter the mainstream and succeeds in driving the cost of ethanol down below the cost of gasoline, the United States could look forward to less energy dependence on the Middle East, reduced greenhouse gas emissions, a renewable fuel source, better performing cars and a boost to the domestic agriculture industry, according to Ethanol Across America, a grassroots organization devoted to promoting ethanol consumption.
Currently the United States produces four billion gallons of ethanol each year at a cost of $10 billion and 11 percent of U.S. corn goes to ethanol production, according to General Motors' "Live Green, Go Yellow" campaign. Chrysler, GM and Ford already manufacture vehicles that run on this type of fuel, and there are over 600 refueling stations across the United States.
Today, a car such as the 2006 GM Cheverolet Suburban, using ethanol and traveling about 15,000 miles a year, would save 16 barrels of oil and use 22,800 corn cobs, according to "Live Green, Go Yellow."
While at Dartmouth, the team received a patent for their discovery which was then licensed to bioethanol startup company Mascome Co. But while Lynd oversaw Zhang's research at Thayer, Zhang recently relocated to Virginia Tech in August of 2005 where he has since made significant improvements to the process. Virginia Tech recently applied for a global patent for his work.
Lynd, who served on the Advisory Committee on Reducing Greenhouse Gas Emissions from Personal Vehicles during the Clinton Administration, has received national attention for his research at Thayer. He has testified twice before the U.S Senate and is co-leading a project called "The Role of Biomass in America's Energy Future."
Currently, Thayer has the largest academic research program in the country in this field, Lynd said. He credits Thayer with providing the type of environment that has allowed his research to flourish.
"I hope to work simultaneously at the fundamental and applied frontiers -- which feels like having my cake and eating it too," Lynd said. "This is an important reason why I choose to work at Thayer School -- you don't have to apologize for working on real problems here."
Dartmouth has not looked into using ethanol to power any of the College's operations.
"Nobody has suggested Dartmouth use ethanol, because none is available locally," Lynd said. "Hiring Jim Merkel as sustainability coordinator was a big step forward, and I am confident that he will formulate exciting recommendations for energy conservation and renewable energy use."
Zhang and Lynd's paper, entitled "Novel lignocellulose fractionation featuring modest reaction conditions and reagent recycling," was presented at the Advances in Fuel Science and Technology session of the 231st American Chemical Society National Meeting.
