Environmental costs and benefits of transportation biofuel production from food- and lignocellulose-based energy crops. A review

Transportation biofuel production in the United States is currently dominated by ethanol from the grain of maize and, to a much lesser extent, biodiesel from soybeans. Although using these biofuels avoids many of the environmentally detrimental aspects of petroleum-based fossil fuels, biofuel production has its own environmental costs, largely related to fossil fuel use in converting crops to biofuels and crop cultivation itself, including ecological damages caused by nitrogen and phosphorus fertilizers, pesticides, and erosion. A new generation of biofuels derived from lignocellulosic sources offers greatly reduced environmental impacts while potentially avoiding conflicts between food and energy production. In particular, diverse mixtures of native prairie species offer biomass feedstocks that may yield greater net energy gains than monoculture energy crops when converted into biofuels, while also providing wildlife habitat and enriching degraded soils through carbon sequestration and nitrogen fixation. Ultimately, as demand for both food and energy rise in the coming decades, greater consideration will need to be given to how land can best be used for the greater benefit of society.