Switch-grass vs Corn

Pimentel and Tad W. Patzek, professor of civil and environmental engineering at Berkeley, conducted a detailed analysis of the energy input-yield ratios of producing ethanol from corn, switch grass and wood biomass as well as for producing biodiesel from soybean and sunflower plants. Their report is published in Natural Resources Research (Vol. 14:1, 65-76).

In terms of energy output compared with energy input for ethanol production, the study found that:
# corn requires 29 percent more fossil energy than the fuel produced;
# switch grass requires 45 percent more fossil energy than the fuel produced; and
# wood biomass requires 57 percent more fossil energy than the fuel produced.

In terms of energy output compared with the energy input for biodiesel production, the study found that:
# soybean plants requires 27 percent more fossil energy than the fuel produced, and
# sunflower plants requires 118 percent more fossil energy than the fuel produced.

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