The Mascoma Corporation, a leading biofuel technology company founded by two Thayer School of Engineering professors, is now producing cellulosic ethanol from sustainable biomass -- a renewable energy source that may one day help power vehicles and reduce the country's dependence on oil -- at its newly constructed pilot facility in Rome, N.Y. While the pilot plant does not produce ethanol on a commercial scale, it is one of the largest U.S. manufacturers of cellulosic ethanol, a wood-derived alcohol that is blended with gasoline to create more sustainable fuel.
"The goal is not to maximize the production of cellulosic ethanol, but rather to demonstrate the process and the equipment," Jim Flatt, Mascoma's executive vice president of research and development, said in an interview with The Dartmouth.
Mascoma could generate between 125,000 and 200,000 gallons of ethanol per year if the demonstration facility produced ethanol continuously, Flatt said. He added that a commercially feasible plant would need to produce around 20 million gallons per year.
The fully-functional pilot plant is an essential step toward the commercial production of cellulosic ethanol, Thayer Dean Joseph Helble said.
"Many people would agree that the future of sustainable fuels is dependent on the development of fuels from cellulosic feedstocks," Helble added. "It's a very significant step."
The demonstration facility, which was completed in December 2008, is the first of its kind to manufacture ethanol using microbes that simplify cellulose fermentation, or the conversion of plant matter to alcohol. The process consolidates many technological steps and lowers costs of ethanol production, Flatt said.
"The biggest trick with cellulosic ethanol is getting the cost down to be competitive with gasoline," Thayer School professor Charles Wyman, co-founder of Mascoma and chairman of its Scientific Advisory Board, said. "Very expensive enzymes are used now for breaking down the cellulose, so the key is driving down that cost, and that's what Mascoma's really targeted directly."
The demonstration facility's success is an important step toward more widespread use of cellulosic ethanol, Flatt said. Producing cellulosic ethanol currently emits 85 to 95 percent less greenhouse gas than the production of gasoline.
"We think we can even be reducing it more than 100 percent, which means you're actually pulling carbon dioxide out during the cycle and making a small reduction," Flatt said.
This reduction is largely due to the facility's ability to use the ethanol-producing biomass as a fuel for further production.
"We remove and dry [the solid] that remains and use it as a fuel to generate steam and electricity to run the process," Flatt said. "You really don't have to use fossil fuel to produce ethanol if you can use the energy available in the biomass. Also, the feedstock that you're using -- the plants and trees -- absorb the carbon dioxide. That's what makes the cellulosic processes so attractive."
Mascoma's pilot plant is the first and largest such facility to use wood as its primary fuel source, another feature of cellulosic ethanol production that Flatt says is environmentally beneficial.
"What's quite advantageous about using wood as feedstock is that it's something that doesn't require the use of any fertilizers or additional water," Flatt said. "You're not displacing food use, and you're not providing any additional burden on the water supply."
Cellulosic ethanol will also provide a more efficient alternative to corn-derived ethanol, which is often mixed with gasoline and used commercially today, Wyman said.
"The challenge with corn is that it's done a great job paving the way for acceptance of alternative fuels, but ultimately, in terms of having a large impact at a very low cost, corn will struggle at some point," Wyman said. "It's already struggling some. We need a much larger resource base."
Cellulosic ethanol production will also reduce the stress ethanol production currently places on the corn industry, Helble said.
"People are producing ethanol from corn, for example, but by diverting corn to produce ethanol, people are arguing that you're removing a food source, driving up the price of food," Helble said. "With cellulosic ethanol, you're not using food materials to produce the fuel."
Flatt recognized that the facility's reliance on hardwood could raise questions about deforestation, but stressed Mascoma's dedication to sustainable plant use.
"The process that we're envisioning is all sustainable, meaning we're only harvesting out of any given area what [the forests] generate the year before," Flatt said. "In terms of the overall ecosystem, we think it can be done in a truly sustainable fashion."
Generating an efficient replacement for gasoline is an important goal in environmental engineering, Wyman said.
"It's getting to the point where oil is at about maximum availability," Wyman said. "We import about two-thirds of the oil we use, and about two-thirds of the oil we use goes to transportation and gasoline, so having a replacement for gasoline is really important."
The pilot plant serves to demonstrate the sustainability and efficiency of cellulosic ethanol in hopes of attracting more funding from investors, Wyman and Flatt said.
"With the current economic climate, actually creating funds for the investment for first-time technology is probably our biggest non-technical challenge," Flatt said. "Right now it's just a very risk-adverse, capital-adverse environment."
Although the economy has created some funding difficulties, it does not pose a serious threat to Mascoma, Wyman said.
"Certainly right now there's difficulties in access to private capital, but I don't think Mascoma's in any danger of shutting down," Wyman said.
The plant was funded in part by grants from the New York State Energy Research and Development Authority and the New York State Power Authority, as well as by Mascoma's investors. Mascoma is headquartered in Boston, Mass., with laboratories in Lebanon, N.H. and Woburn, Mass.
