A new analysis of two commercial biofuels finds that while both provide more energy than they consume, soybean biodiesel gives more bang for the buck than ethanol made from corn does.
Corn-grain ethanol and soybean biodiesel are the two major alternative transportation fuels in the United States. The biofuels can replace gasoline and diesel, respectively. A team of Minnesota ecologists and economists set out to add up all the energy and environmental costs and benefits of the two food-based biofuels.
The researchers included the energy required to grow the crops, run farm machinery, manufacture fertilizers and pesticides, transport the crops, and transform the raw material into fuel. They also considered the environmental impact of the added fertilizers and pesticides.
Both biofuels yield energy, but with corn-based ethanol, "it takes so much energy to grow the corn and convert it into a fuel, you don't gain very much energy in the overall process," says ecologist