sumes that vehicles are 5 years older and assigns them the corresponding emissions. When using GREET to evaluate vehicles in 2005, emissions from vehicles correspond to year 2000. However, all other values in GREET’s assessment (such as fuel sulfur levels or electricity mixes) correspond to 2005.

The 2030 assessment is outside the GREET temporal upper range, so 2020 is used as a baseline (although adjustments are made and described later in this section).

GREET Vehicle-Manufacturing Emissions

The GREET 2.7a model was used to determine vehicle-manufacturing emissions. The model performs a life-cycle assessment from vehicle material inputs to determine emissions from manufacturing for cars and SUVs. The model distinguishes between internal-combustion-engine vehicles, hybrid electric vehicles, and fuel-cell electric vehicles from both conventional and light-weight materials. The material inputs are evaluated for the body, powertrain system, transmission system, chassis, battery, fluids, paint, traction motor, generator, electronic controller, and fuel-cell auxiliary system. These components are assessed from material extraction through assembly, and emissions are determined at each stage. Disposal is included.

There is no time dependency with GREET’s vehicle-manufacturing assessment, so process changes from 2005 through 2030 are not captured. Energy and emission factors are determined for the vehicle size, powerdelivery systems, and material-composition combinations, as shown in Table D-1 and Table D-2.

The car conventional-material factors are used for all light-duty autos, and the SUV conventional-material factors are used for light-duty trucks class 1 and 2.

GREET Light-Duty Auto and Truck Energy and Emissions Factors

Light-duty automobile and truck life-cycle energy inputs and emissions are determined from GREET. GREET distinguishes between light-duty trucks class 1 and 2 to capture the increased energy requirements and resulting emissions of the larger vehicles. Class 1 trucks are between zero and 6,000 lb gross-vehicle-weight rating (GVWR) and less than 3,750 lb loaded vehicle weight (LVW), and class 2 trucks have the same GVWR and greater than 3,750 LVW. For each vehicle and fuel combination, GREET is used to determine feedstock, fuel, and operational factors for light-duty autos, trucks in class 1 (LDT1), and trucks in class 2 (LDT2).

GREET allows for the adjustment of many vehicle and fuel parameters; however, certain critical parameters are adjusted some of the vehicle and fuel combinations to estimate life-cycle emissions. For reformulated gaso-



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