Why not in New England?
"Because ethanol is made mostly in the Midwest," explains Wyman. "There are also places that benefit from using ethanol. In Denver, for instance, ethanol helps gasoline burn cleaner at the mile-high altitude, particularly in older cars."
Although corn ethanol and cellulosic ethanol are chemically identical, important features of the life cycle of ethanol production and utilization are different for the two feedstocks. Corn ethanol has many desirable attributes, but energy balance, net greenhouse gas emissions, and environmental appeal are still better for production from cellulosic materials. Plus, cellulosic biomass is a more abundant resource than the corn starch and sugars used now to make ethanol in the U.S. and Brazil, respectively.
A substantial portion of cellulosic biomass consists of the insoluble carbohydrates cellulose and hemicellulose. The processes Wyman and Lynd envision involve pretreatment to make biomass accessible to cellulase enzymes followed by enzymatic hydrolysis and fermentation. When the carbohydrate ferments, a residue rich in a compound called lignin remains. This residue can be used to provide all the heat and electricity needed to run a cellulosic ethanol processing facility, with some excess electricity left to export. Because photosynthesis is a carbon dioxide- consuming process, the entire cycle of plant production, ethanol production, and ethanol utilization has near-zero net emissions of greenhouse gases.
"Our overall approach is distinctive," says Lynd. "We're saying, 'What can we do to improve sustainability, and what are the tools we need?' These tools include applied biology, chemistry, process engineering, and resource and environmental efficacy analysis."
Wyman works in the process-engineering realm developing new pretreatment processes to break down the cellulosic material to its component sugars. Lynd works in the applied biology realm, genetically engineering microorganisms to make enzymes, which break down cellulose to glucose, and ferment all sugars into ethanol. They both investigate various aspects of biochemical engineering as well as process design and evaluation.
Wyman and Lynd acknowledge there are substantial hurdles to making cellulosic ethanol commercially successful. Although progress is often slow to advance the technology needed to convert cellulosic biomass to ethanol, both of their research groups are working on breakthrough opportunities.
"We're knocking on the door of some revolutionary advances," says Lynd.
There are more hurdles to clear, however.
"To seriously pursue this, I think the government needs to invest more money in bioenergy research and development," says Lynd.
"Government investment in energy research and development is less now, in comparable terms, than it was in 1973, and industrial investment in fundamental research and development has been declining since the 1980s. This does not square with the challenges facing the world on both the sustainability and security fronts."
Lynd and Wyman see cellulosic ethanol as having potential to be the primary mode of energy storage for a sustainable transportation sector over the long term.
"Although hydrogen has merit in this context," says Wyman, "cellulosic ethanol is very promising, and it is a mistake to limit our options."
Over the next two years, Wyman and Lynd will participate in an initiative called "The Role of Biomass in America's Energy Future." The program, led by Dartmouth and the National Resources Defense Council and supported by the U.S. Department of Energy and the Energy Foundation, will tackle overall resource availability and policy strategies.
"Doing a comprehensive analysis with a forward-looking orientation and a broad cast of participants from different sectors-environmental, technical, energy policy-is a giant step," says Lynd, who helped organize the effort and sits on the steering committee.
Wyman and Lynd are well on their way to revolutionizing our transportation energy needs as we know them.