CELLULOSIC BIOFUEL: Instead of producing ethanol from corn via fermentation, new techniques could produce grassoline from otherwise unused biomass.
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Editor's Note: George W. Huber and Bruce Dale are chemical engineers at the University of Massachusetts Amherst and Michigan State University, respectively.

In this article, a rough draft of which appears below, Huber and Dale point out that biofuels remain one of the most technically promising alternatives to oil. The key will be learning to convert cellulosic biomass (like stalks and stems, and unlike edible cereal corn, which is noncellulosic) into fuel. Please help us edit the following piece by suggesting factors the researchers may have overlooked or refinements to their argument.

Here are some questions to get started:

What is your reaction to their assertion that "huge amounts of cellulosic biomass can be sustainably harvested to produce fuel"?

What do you think are the most promising avenues of exploration in figuring out how to deconstruct cellulosic material?

What other viable biofuel manufacturing processes might Huber and Dale want to consider?

Do Huber and Dale present a persuasive case that cellulosic biofuels are the most technically promising alternative to oil?

What is your reaction to their assertion that the "raw feedstocks that go into making the biofuel are far less expensive than raw crude?"

How do you think a "move toward 'grassoline'" would "fundamentally change the world"?

Your feedback will be considered by the writers and editors as they complete the final draft of this article, which will appear in an upcoming edition of Scientific American magazine.

By now it ought to be clear that we must get off oil. We can no longer afford the dangers that our overwhelming dependence on petroleum poses for our national security, our economic security or our environmental security. Yet civilization is not about to not stop moving, and so we must develop a new way to power the world’s transportation fleet. Biofuels, or liquid fuels made from plant material, remain the most technically promising alternative.

Biofuels can be made from anything that is, or ever was, a plant. First-generation biofuels are made from edible biomass such as corn or sugarcane. Although we already possess the technology to convert these feedstocks into fuels (as evidenced by the nearly 200 refineries currently processing corn into ethanol in the U.S.),  there is simply not enough corn, sugar cane or vegetable oil to provide more than about 10 percent of the liquid fuel needs of developed countries such as ours. These first generation biofuels also compete for farmland with crops used for human food and animal feed, which complicates the calculations of the environmental costs and benefits associated with them. We need biofuel raw materials that are cheap, abundant and that do not interfere with food production.

The winner in all three categories is cellulosic biomass—woods, grasses and inedible stalks of plants. Fuel made out of this biomass—what we’ll call “grassoline”—could come from dozens, if not hundreds, of potential sources, from wood residues such as sawdust and construction debris, to agricultural wastes such as corn stalks, to “energy crops”—fast-growing grasses and woody materials that are grown expressly for their energy content.

Huge amounts of cellulosic biomass can be sustainably harvested to produce fuel. According to an upcoming study by the U.S. Department of Agriculture and Department of Energy, the U.S. can produce at least 1.3 billion dry tons of cellulosic biomass every year, and all without decreasing the amount of biomass available for our food, animal feed or exports. This much biomass could produce more than 100 billion gallons per year of grassoline, or about half the current annual consumption of gasoline and diesel in the U.S. Similar projections estimate that the global supply of cellulosic biomass has an energy content equivalent to between 34 billion to 160 billion barrels of oil per year, numbers that exceed the world’s current annual consumption of 30 billion barrels of oil. And unlike biofuel made from corn, cellulosic biomass can be converted to any type of fuel—ethanol, ordinary gasoline, diesel or even jet fuel.