By Deborah Halber, MIT
Mar 11, 2007, 19:46
We'll be filling our tanks with ethanol made from prairie grass while producing no greenhouse gases and improving agricultural soil in the bargain, if Lee R. Lynd has his way.
Lynd, a professor of engineering and biology at Dartmouth, spoke to an overflow crowd in Bartos Theater last week about how to create an environmentally sustainable future by substituting biomass-derived fuels for fossil fuels for transportation.
Lynd spoke on "The Role of Biomass in America's Energy Future," presenting results from an ongoing multi-institution project by the same name. The study is looking at two dozen scenarios in which biomass fuels could become cost-competitive with gas over a range of oil and power prices.
The mass energy yield of oil is very high, almost 80 units per 100 processed. "To make a serious dent in oil refining, the results would have to be impressive," Lynd said.
Cellulosic ethanol produced from native prairie perennial switchgrass, plus agricultural forestry and municipal residues such as wood chips and paper sludge, has the greatest potential to become a viable primary transportation sector energy carrier, he said. Lynd said that it is "likely that cellulosic ethanol can eventually be produced on an unsubsidized basis at costs comparable to the cost of gasoline production." Among its benefits are essentially zero net emissions of greenhouse gases and improved fertility from the carbon that switchgrass replaces in the soil as it grows.
The researchers investigating biomass chose to focus on switchgrass, not corn or soy, because food crops are not necessarily the most productive energy sources. Yet in future scenarios, Lynd said, farmers would rotate switchgrass with food crops.
"In my view, people have underestimated the importance of biomass in the context of using limited earth space to produce human needs such as food and energy," Lynd said.
Even if the United States and other countries embrace this vision as a goal, a lot will have to happen before it becomes a reality. Continued technological innovation to make biomass more productive, coupled with new, highly efficient vehicles and farmers agreeing to grow switchgrass or other "energy crops" as part of the overall agricultural system, would all be necessary for a transition from fossil fuels to biomass fuels.
And this is for an alternative fuel that rarely gets lip service, although Lynd pointed out that President Bush mentioned biomass in his State of the Union address last week.
During the Industrial Revolution, resources were plentiful and people scarce. Now that the opposite is true, we need a second Industrial Revolution to create the technology to fix the mess we've gotten ourselves into, Lynd said.
"Our best chance of successfully navigating the sustainable resource transition is based on aggressive and effective efforts devoted to innovation and increased resource utilization efficiency," Lynd said. "Without both of these complementary strategies, we are far less likely to be successful in this endeavor."
Biomass conversion to fuel depends on fermentation and hydrolysis, among other techniques. Lynd said results would come faster with the help of genetically engineered plants. "This is a challenging job for metabolic engineering. That kind of energy hasn't been brought to this field, but some really elegant things have been done in pharmaceuticals. If we've done that, we can do this."
Lynd noted that "there are also very important questions about effective policy formulation and the willingness of society to make the changes needed to accommodate this, or any other, path to a sustainable and secure energy future."
Lynd's talk was the second in a series of colloquia sponsored by MIT's Energy Research Council and the Laboratory for Energy and the Environment.
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