and major modifications made to the original VISION model in developing VISION-NRC (Section H.1.3). For more information on the VISION model and to download the model itself, see the attached Appendix H VISION Model Spreadsheet.

H.1.2 VISION-NRC Scenarios

To explore possible paths to attain the goals, VISION-NRC was run for a range of cases. The predominant characteristic of these runs was to focus on a market dominated by a particular vehicle type and alternative fuel (i.e., battery electric vehicles (BEVs), fuel-cell vehicles). To assess the range of possibilities, the committee looked both at runs that used the midrange vehicle efficiencies for these advanced vehicles as well as runs that used the optimistic efficiencies to represent technological breakthroughs, as described in Chapter 2 and summarized in Table 2.11. From the fuels side, the committee considered both business-as-usual (BAU) production of a fuel (gasoline, hydrogen, or electricity) as well as a low-GHG fuel supply technologies, as described in Chapter 3 (low-net-GHG biofuels, H2 generation with carbon capture and storage (CCS), or a low-GHG electric grid).

Some of the key assumptions throughout all of the runs are listed below.

• There are two “reference cases” in the committee’s analysis. There is the BAU Case, which is basically the AEO 2011 assumptions, and then there is the Committee Reference Case, which includes, instead of the AEO assumptions, all of the committee assumptions about vehicle efficiencies, fuel carbon intensity, and effects in the future of existing regulations (see below).

• All runs of the model, except the AEO BAU Case, use the committee’s assumptions on vehicle efficiencies, GHG impact of the fuels supplied, and availability of resources. Committee estimates of vehicle fuel efficiencies can be found in Table 2.12 of Chapter 2.

• Total new vehicle sales each year are drawn from the AEO 2011 Reference Case and do not change with the different runs, only the mix of vehicles changes; VMT per vehicle is from AEO Reference Case forecast and falls over time as vehicles age; total VMT of the fleet is the same for each run and is consistent with the AEO 2011 assumptions about total VMT over time (see Table H.1).

• Oil prices are taken from AEO 2011 and are expected to gradually increase to $125/barrel by 2035, resulting in a pre-tax gasoline price of $3.16 in that year. Gasoline prices are then extrapolated out to 2050, assuming the compound rate of growth modeled in AEO 2011 from 2030-2035. The current gasoline tax of $0.42/gallon is assumed to hold true out to 2050.

• VMT per year for battery electric vehicles (BEVs) are assumed to be two-thirds that of other vehicles, due to battery range limitations.

• The shares of new vehicles sales by type of vehicle (hybrid electric vehicle [HEV], plug-in hybrid electric vehicle [PHEV4], fuel cell electric vehicle [FCEV], etc.) are from AEO Reference Case for our BAU run; for the committee scenarios, shares are assumed to change as specified in Table H.1. In the scenarios where alternative vehicles are assumed to enter the fleet in large numbers, it is assumed that new vehicle shares never increase by more than 5 percentage points of the new vehicle stock in any given year.

• Only one PHEV, a PHEV-30, with a real world all-electric driving range of 25 miles—this yields a utility factor of 46 percent is included.

• GHGs from biofuels include both direct emissions from production and also emissions from indirect effects on land use (see Chapter 3).

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4 BEVs and PHEVs are collectively known as plug-in vehicles (PEVs).



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