TABLE 4.3 Potential Reductions in Petroleum Use and Greenhouse Gas Emissions from Vehicle Efficiency Improvements over the Next 25 Years

Propulsion System

Vehicle Petroleum Consumption (gasoline equivalent)a

Greenhouse Gas Emissionsa

Relative to Current Gasoline ICE

Relative to 2035 Gasoline ICE

Relative to Current Gasoline ICE

Relative to 2035 Gasoline ICE

Current gasoline

1

1

Current turbocharged gasoline

0.9

0.9

Current diesel

0.8

0.8

Current hybrid

0.75

0.75

2035 gasoline

0.65

1

0.65

1

2035 turbocharged gasoline

0.57

0.89

0.57

0.88

2035 diesel

0.55

0.85

0.55

0.85

2035 HEV

0.4

0.6

0.4

0.6

2035 PHEV

0.2

0.3

0.35–0.45

0.55–0.7

2035 BEVb

0.35–0.5

0.55–0.8

2035 HFCVb

0.3–0.4

0.45–0.6

Note: These estimates assume that vehicle performance and size (acceleration and power-to-weight ratio) are kept constant at today’s levels. BEV, battery-electric vehicle; HEV, hybrid electric vehicle; HFCV, hydrogen fuel-cell vehicle; ICE, internal-combustion engine; PHEV, plug-in hybrid vehicle.

aGreenhouse gas emissions from the electricity used in 2035 PHEVs, 2035 BEVs, and 2035 HFCVs are estimated from the projected U.S. average electricity grid mix in 2035. Greenhouse gas emissions from hydrogen production are estimated for hydrogen made from natural gas.

bThe metric “vehicle petroleum consumption” is not applicable to vehicles powered by batteries and hydrogen fuel cells. Estimated greenhouse gas emissions are those resulting from production of the needed electricity and hydrogen. Source: Bandivadekar et al., 2008.

PHEVs are likely to become more widely available in the near term to midterm, whereas BEVs and FCVs are high-volume alternatives for the midterm to long term.

Deployment of Light-Duty Vehicle Technologies

To have a significant effect on fuel use in the vehicle fleet and on associated CO2 emissions, advanced-technology vehicles must garner a sizable market share. Generally, however, a decade or more elapses in developing a technology to a stage that it can be deployed, introduced on a commercial vehicle, and then achieve significant sales. There are also technical constraints on the speed with which the



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