How do second-generation biofuels work?

The Trouble With Biofuels

The summer of 2012 was hot and dry across much of the United States, especially the Midwest, America's breadbasket. Arid conditions withered corn and other grain crops, driving up prices and straining an already weak economy.

The historic drought, the worst in 50 years, highlighted the limitations of first-generation biofuel feedstock. As food prices skyrocketed, farmers, bureaucrats and politicians began debating the wisdom of diverting food crops to biofuel production. It was a scene being played out in an increasingly hot, dry and hungry world. The problem got so bad that food aid groups and the United Nations began asking governments to scrap biofuel production mandates in order to allow for more food production. The U.N. said that when the world faces a shortage of food, countries should rethink their biofuel policies [source: Blas].

In addition to contributing to a food crisis, producing ethanol and biodiesel from feedstock is not as environmentally and economically friendly as you might think. First-generation biofuels are made from sugars and starches that are easily digested by yeast. If refineries turned every ear of corn into ethanol, it would replace only 12 percent of the gasoline supply [source: Brune].

Additionally, farmers use copious amounts of fossil fuel, water and fertilizers to grow and process first-generation feedstock into biofuel. The growing and manufacturing process that turns corn into ethanol, for example, produces only 15 percent less greenhouse gas than gasoline [source: Tilman and Hill].

Fortunately, there's a new generation waiting to step in. Unlike biofuel made from corn, soybeans or other first-generation feedstock, second-generation biofuels are made from plants that no one wants to eat. Although it's a difficult process to turn the waste products from plants, such as corn stalks, stems, leaves, husks and wood chips into biofuel, the potential benefits are enormous. Second-generation technology can make much more fuel than first-generation biofuels, minimally affecting the food supply and environment.

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