Achievement

Estimating the greenhouse gas balance of biofuel is critical to understanding its ability to reduce emissions. Producing accurate balances is difficult because of uncertainty surrounding emissions of gases like nitrous oxide (N2O) from agricultural land used to grow feedstocks. N2O has a global warming potential 298 times greater than carbon dioxide, so accurate estimates are critical. This study measures emissions of N2O from soils of prospective cellulosic biofuel crops in Kansas. We compared the measured emissions to emission factors commonly used to estimate N2O emissions in biofuel greenhouse gas balances. Finally, the measured emissions and crop yield data were used as inputs into a life cycle analysis model which estimates the greenhouse gas balance of cellulosic biofuels. This study found that N2O emissions from soils can represent a major greenhouse gas source in cellulosic ethanol production and that current estimates may not sufficiently account for N2O emissions.