Kelly Tiller, a professor at the university's Agricultural Policy Analysis Center and one of the program coordinators, said the aim of the project is to solve cellulosic ethanol's chicken-and-egg problem: Farmers won't grow switch grass without first finding a buyer, and investors won't build a plant without growers. She said farmers are excited about the project: One acre of switch grass is enough to produce 1,000 gallons of ethanol a year at a production cost of less than $300.
Even if farmers are willing to grow switch grass, will investors be willing to build plants to refine it? Thomas Foust, the biofuels research director for the Department of Energy's National Renewable Energy Laboratory in Colorado, says that using current technology, and assuming a 10 percent rate of return on investments, a gallon of cellulosic ethanol can be produced for between $2.10 and $2.40 a gallon—without government subsidies. By 2012, Foust expects to bring that cost down to $1.35 per gallon.
The impact of cellulosic ethanol on greenhouse-gas emissions seems equally clear. Because the lignin isn't a sugar, it can't be converted to ethanol. But according to Foust, that lignin can be used to fuel the refining process, which means that cellulosic ethanol fuels its own refinement—a modern-day version of alchemy. "That's why climate change scientists are lukewarm about corn-based ethanol but pretty excited about cellulosic," said Foust, "because it'll show an 85 percent reduction in [greenhouse gases] over gasoline."
The benefits of cellulosic ethanol come with a crucial caveat. In February, Timothy Searchinger, a researcher at Princeton, published a paper in Science arguing that while cellulosic ethanol reduced direct greenhouse-gas emissions, it actually increased emissions if you took into account the changes in land use that result elsewhere.
"If you were to grow switch grass on corn land in the U.S., it would result in a 50% increase in [greenhouse gases]," said Searchinger, "because when you divert an acre of corn land, most of that acre will be replaced somewhere around the world." And because farmers in other countries often produce lower yields per acre, replacing those acres overseas often means more land is needed to produce the same amount of food.
In order to reduce greenhouse-gas emissions, and also to avoid increasing the price of food, Searchinger said the biomass used for cellulosic ethanol must be grown on land that wouldn't otherwise be used to grow crops. And even that rule isn't straightforward. "If you take a hectare that's not being used for food today," Searchinger said, "it might very well be a hectare that we're going to need for food tomorrow."
Can we grow enough plant material on marginal land for cellulosic ethanol to become our next big energy solution? Maybe not. But, then, maybe that's the real lesson of the biofuels flip-flop—the need to be wary of promises of a big fix.