(491b) Regional Variations in N2O Emissions From Rotation Cropping of Rapeseed With Winter Wheat
To reduce petroleum dependency and economic cost of conventional jet fuel, Hydrotreated Renewable Jet (HRJ) fuel from oilseed plants has become increasingly important for the aviation sector. Rapeseed (Brassica Napus) is now considered as feedstock for HRJ because it has high potential for producing more HRJ fuel than jatropha, camelina, and soybean. The purpose of this research is to evaluate the importance of regional differences in N2O releases to the GHG emissions of rapeseed HRJ fuel. The Roundtable on Sustainable Biofuels (RSB) methodology was applied to determine regional N2O emissions in several counties in 10 U.S. wheat-growing states where rapeseed cultivation as a rotation crop is being considered: Kansas (KS), Montana (MT), North Dakota (ND), Nebraska (NE), Oklahoma (OK), Oregon (OR), Texas (TX), South Dakota (SD), and Washington (WA). The results of N2O emissions were compared to the Intergovernmental Panel on Climate Change (IPCC, 2006) guidelines. The results show that the RSB-calculated N2O emissions varied for different U.S. states. N2O emissions were highest in OR (0.73 kg N2O ton-1 seed) whereas NE had the lowest N2O emissions (0.72 kg N2O ton-1 seed), while N2O emissions from IPCC (2006) were the same for all sites, 0.87 kg N2O ton-1 seed. The life cycle GHG emissions of rapeseed HRJ using RSB method were in the range of 42.66 - 42.97 g CO2eq/MJ depending on state compared to 45.86 g CO2eq/MJ using IPCC method.