addressed in this study are discussed in Section 3.
Table 1-1: Fuels, Feedstocks, and Refining Processes Evaluated in this Study
Diesel, reformulated diesel, LPG
Methanol, synthetic diesel, LPG
For the purposes of this study, fuel-cycle emissions represent fuel extraction, production, distribution, and vehicle conversion as illustrated in the example for diesel processing in Figure 1-1. This definition is often referred to as “well to wheels”. The analysis considers the marginal, or incremental gallon (or equivalent fuel unit) consumed in the South Coast Air Basin (SoCAB). In order to help evaluate the impact on air quality, the emissions will be geographically categorized. Energy needed for fuel production in the South Coast Air Basin will also be sorted to count sources that correspond to incremental fuel production.
Fuel-cycle emissions were analyzed over a range of assumptions. The major factors that affect fuel-cycle emissions in this study include the following:
Vehicle fuel economy (which is proportional to fuel-cycle emissions)
Reduction in emissions due to stationary control measures in Southern California
Different alternative fuel production feedstocks and technologies
Control of vehicle refueling emissions
Emissions were estimated for conditions in 1996 and 2010 with emission regulations, and vehicle fuel economy consistent with these time periods. These estimates serve as upper and lower bounds. Table 1-2 shows the scenarios explored in this study.
A significant fraction of the new vehicle mix in the year 2010 is expected to be comprised of SULEVs and ultra-low-emission vehicles (ULEVs). This time period is appropriate for the evaluation of fuel-cycle emissions since a significant fraction of these vehicles may be alternative-fueled or powered by hybrid electric drivetrains.