We use a lot of biofuels in the US -- corn ethanol now makes up 10% of every gallon of gasoline. Ethanol made from cellulose, from agricultural waste or non-food crops, has been in development for years and may eventually become commercial, along with new kinds of aviation biofuels. Valerie Reed, Bioenergy Director at the DOE, and Yiying Xong from the Great Lakes National Laboratory discuss.