Sensitivity analysis of fleet-level life cycle carbon emissions to biofuel options and emission policy schemes for the U.S. commercial airlines

There is a need for different approaches to study fleet-level impact analyses involving biofuel options, emission policy schemes, and advanced level of aircraft technologies. This paper present an approach to assess accumulative life cycle carbon emissions from 2005 to 2050 under scenarios with alternative fuels and emission policy schemes along with uncertainties on alternative biofuel sources and some economic factors. The approach centers on the combination of two tools, the Fleet-Level Environmental Evaluation Tool and MultiActor Life Cycle Assessment Biofuel Model. Two emission policy schemes: the European Union Emission Trading Scheme and the International Civil Aviation Organization Global Market-Based Measure. The simulation outcomes provides two major insights. First, the International Civil Aviation Organization Global Market-Based Measure scheme model is more likely to result in lower cumulative carbon emissions than those of European Union Emission Trading Scheme. Second, factors related to biofuel options that have strong impact on fleet-level carbon cycle emissions include biorefinery firms profitability threshold and material and energy inputs to biofuel production from camelina, corn stover, and switchgrass.