2013 Annual Report
1a.Objectives (from AD-416):
Develop life-cycle assessments (LCAs) informed by inputs from multiple landscape scales to evaluate the environmental impacts of land-use change on greenhouse gas emissions, fossil energy demand, and water use.
1b.Approach (from AD-416):
Cooperator will assess the environmental indicators listed above for the proposed processes to convert Brassica crop (rapeseed) to hydrotreated renewable jet (HRJ) fuel. Inputs will be received from each project team across the production chain and LCA results will be communicated frequently back to the Feedstock Development and Biofuel Development project team components. Preliminary LCA data for renewable fuel production will be developed using laboratory or literature data from the project partners. In addition to the process-level data received (attributional inputs), the LCA will also include inputs from indirect effects of the production system, so called consequential inputs that have not been thoroughly investigated for their impacts on the sensitivity of LCAs. The consequential inputs will come from “beyond system boundary” effects captured in the modeling efforts involving EPIC, SWAT, and GTAP on indirect effects that affect water quality and indirect land use change emissions of CO2 and other greenhouse gases. LCA results will be communicated early in the project and continue throughout the four-year program. These communications (inputs to the LCA and LCA results) will help achieve a cohesive and integrated research program and will aid in focusing the research team members on actions to overcome barriers to sustainability and protection of the environment.
Work under this agreement was conducted under the funded National Institute of Food and Agriculture (NIFA) Biomass Research and Development Initiative (BRDI) grant for the development of hydrotreated renewable jet (HRJ) fuel from brasssica rotations in the wheat belt of the western U.S. ARS scientists in the Bio-Oils Research Unit at the USDA-ARS National Center for Agricultural Utilization Research, Peoria, Illinois, are engaged in research to develop renewable jet fuel from brassica, as well as analyzing germplasm and conducting seed oil processing research for this effect. The work under this agreement is specifically directed toward the development of a "cradle to grave" life cycle assessment (LCA) for the development of HRJ fuel from brassica in rotation with wheat. The research first evaluated regional differences in nitrous oxide (N2O) emissions, one of the main contributors to greenhouse gas (GHG) emissions in the brassica HRJ fuel pathway. The Roundtable on Sustainable Biofuels (RSB) method was used in order to model variations in GHG emission for N2O emissions in several counties in 10 U.S. states (California, Kansas, Montana, North Dakota, Nebraska, Oklahoma, Oregon, Texas, South Dakota, and Washington) and those results were compared to the Intergovernmental Panel on Climate Change (IPCC) “Tier I” guidelines. In this study, rapeseed was assumed to be cultivated as a rotation crop with wheat according to the rotation schedule planned for in this project. The nitrogen (N) fertilizer application rate, N fertilizer type, and rapeseed yield were maintained to be the same in each state in order to compare and contrast the RSB and IPCC methods for N2O emissions. The RSB-calculated N2O emissions varied across the U.S. rapeseed cultivation regions, though regional variations resulting from ammonia (NH3) volatilization and nitrate leaching were very small, in the range of 0.72-0.73 kg N2O Mg-1 seed, which was lowest in NE and highest in OR. The N2O emissions results from the IPCC method were the same for all the sites, at 0.87 kg N2O Mg-1 seed. The sensitivity analysis of rapeseed yield at ±500 kg ha-1 was conducted assuming constant fertilizer inputs in order to estimate the influence of yield on N2O emissions. The N2O emissions from the RSB and IPCC methods were increased by 17-18% with decreased yield and reduced by 12-13% with increased yield. Secondly, we focused on a preliminary analysis of GHG emissions baseline of rapeseed HRJ fuel due to regional variation in N2O emissions using the displacement allocation. The data inputs of cultivation, oil extraction, HRJ fuel conversion, transportation, and combustion were mostly taken from the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model, a well-known biofuel pathway LCA tool published by the Argonne National Laboratory. The preliminary GHG emissions baseline of rapeseed HRJ fuel using the RSB method were in the range 42.66-42.97 g CO2 eq/MJ, which achieved the GHG savings of greater than 50% compared to conventional jet fuel for multiple regional sites. Conversely, the GHG emissions from the IPCC method were the same for all locations, and slightly under the GHG saving threshold of 50%.
This research is calculating direct land use change (dLUC) emissions of GHGs which was measured as changes in soil organic carbon (SOC) stocks due to various management practices in 10 U.S. states using the IPCC guidelines (approach.
2)applied for wheat-rapeseed crop rotation every three years. These preliminary results showed that high wheat residue left on the field without tillage practice had the best result for increasing soil carbon stocks.