TABLE H.1 Assumptions Taken from AEO 2011; These Hold for All VISION Cases
|Total LDV sales, 1000s/year||16,766||18,502||22,219|
|Stock of LDVs, millions||234.6||282.2||365.2|
|Share of cars, percent of total fleet|
|Total VMT, trillion VMT||2.69||3.76||5.05|
|Average VMT a VMT/LDV||11 455||13 316||13 822|
a Average VMT is assumed to two-thirds of this for BEVs.
A detailed overview of the different VISION cases is provided below, with Table H.2 summarizing the differences. For more information on fuel efficiency assumptions of vehicles, see Table 2.12. For more information on the carbon rates of different fuels, see Table 3.4 in Chapter 3.
• AEO BAU Case. Uses AEO 2011 Reference Case assumptions on VMT, vehicle shares, vehicle efficiencies, fuels shares, and fuel GHG impacts. AEO forecast only is made to 2035. VMT was extrapolated to 2050 assuming a 1.5 percent growth rate from 2036 to 2050. Corporate Average Fuel Economy (CAFE) standards are only assumed to be specified through the 2016 model year, but not beyond. This case assumes a small amount of coal to liquid (CTL) fuel and gas to liquid (GTL) fuel is introduced by 2035.
• Committee Reference Case. The Committee defines its own reference case that includes all of the midrange assumptions about vehicle efficiencies, fuel availability, and GHG impact developed by the committee (summarized in Chapters 2 and 3). In addition, this case assumes that the recently finalized 2025 CAFE and GHG standards for fuel efficiency of light-duty vehicles (LDVs) will be met, and the standards will then stay at that level through 2050. The standards are interpreted to require that new vehicles in 2025 must have on-road fuel economy averaging about 41 mpg (given a fleetwide CAFE rating of 49.6 mpg). New vehicle sales shares are adjusted to meet this standard—primarily, advanced internal combustion engine vehicle (ICEV) and HEV shares are increased. After 2025, there is a very small annual improvement in average fuel consumption (~0.3 percent), which is consistent with the AEO2011 projection. This case also assumes that the federal Renewable Fuels Standard (RFS2) will be met by 2030. As a result, corn ethanol sales rise to about 10 billion gallon of gasoline equivalent (gge) per year by 2015 and stay at that level through the period. And, based on the analysis in Chapter 3, it is assumed that all cellulosic biofuels will be thermo-chemically derived drop-in fuels. The RFS2 requirements result in production of 14 billion gge per year of such biofuels by 2030, and it is assumed that they remain roughly constant after that time.
• Emphasis on ICE Vehicle Efficiency. A set of model runs that continue the focus on light duty fuel efficiency improvements through the period to 2050. Shares of advanced ICEVs and HEVs increase to just over 80 percent of new vehicles by 2050. Two runs are included that differ only in their assumptions about the fuel efficiency improvements of vehicles over time. The first assumes the midrange assumptions for fuel efficiency for all technologies (Chapter 2, Table 2.12), and the second assumes optimistic fuel efficiency for ICEs and HEVs, while maintaining midrange values for the small numbers of other types of vehicles in the fleet. It is assumed that the RFS2 requirements described above (under the Committee Reference Case) are still in place, bringing in some corn ethanol and cellulosic biofuels. These increased vehicle efficiency cases require much less liquid fuel over time, and it is assumed that the fuel backed out is gasoline.
• Emphasis on ICE Vehicle Efficiency and Biofuels. Two runs are similar to the Committee Reference Case and the emphasis on efficiency case, with the difference that more biofuels are brought into the market after 2030. The amount of biofuel brought to the market rises to the limit specified by the