Implications of sustainability for the United States light-duty transportation sector

This article presents a cradle-to-grave (C2G) assessment of greenhouse gas (GHG) emissions and costs for current (2015) and future (2025-2030) light-duty vehicles. The analysis addressed both fuel cycle and vehicle manufacturing cycle for the following vehicle types: gasoline and diesel internal combustion engine vehicles (ICEVs), flex fuel vehicles, compressed natural gas (CNG) vehicles, hybrid electric vehicles (HEVs), hydrogen fuel cell electric vehicles (FCEVs), battery electric vehicles (BEVs), and plug-in hybrid electric vehicles (PHEVs). Gasoline ICEVs using current technology have C2G emissions of ∼450 gCOe/mi (grams of carbon dioxide equivalents per mile), while C2G emissions from HEVs, PHEVs, H FCEVs, and BEVs range from 300-350 gCOe/mi. Future vehicle efficiency gains are expected to reduce emissions to ∼350 gCO/mi for ICEVs and ∼250 gCO/mi for HEVs, PHEVs, FCEVs, and BEVs. Utilizing low-carbon fuel pathways yields GHG reductions more than double those achieved by vehicle efficiency gains alone. Levelized costs of driving (LCDs) are in the range $0.25-$1.00/mi depending on time frame and vehicle-fuel technology. In all cases, vehicle cost represents the major (60-90%) contribution to LCDs. Currently, HEV and PHEV petroleum-fueled vehicles provide the most attractive cost in terms of avoided carbon emissions, although they offer lower potential GHG reductions. The ranges of LCD and cost of avoided carbon are narrower for the future technology pathways, reflecting the expected economic competitiveness of these alternative vehicles and fuels.

Section: Resultsmentioning

confidence: 99%

Current and Future United States Light-Duty Vehicle Pathways: Cradle-to-Grave Lifecycle Greenhouse Gas Emissions and Economic Assessment

Elgowainy

Han

Ward

et al. 2018

“…Driven by economic pressures, market competition, and environmental regulations, auto manufacturers are actively pursuing technological solutions to reduce the greenhouse gas (GHG) emissions associated with personal transportation. Although much of the recent discussions of automotive technology change center around electrification of the drivetrain, − there are, in fact, other technology strategies that can reduce vehicle fuel consumption. − One important strategy is mass reduction, which the industry refers to as lightweighting. − By reducing the mass of the vehicle, the inertial forces and rolling resistances that the engine has to overcome are lowered, and the energy required to drive the vehicle is reduced. Assuming that vehicles stay about the same size, substantial mass reduction generally requires material substitution. − …”

Section: Introductionmentioning

confidence: 99%

Regional Heterogeneity in the Emissions Benefits of Electrified and Lightweighted Light-Duty Vehicles

Guo

Field

et al. 2019

Electrification and lightweighting technologies are important components of greenhouse gas (GHG) emission reduction strategies for light-duty vehicles. Assessments of GHG emissions from light-duty vehicles should take a cradle-to-grave life cycle perspective and capture important regional effects. We report the first regionally explicit (county-level) life cycle assessment of the use of lightweighting and electrification for light-duty vehicles in the U.S. Regional differences in climate, electric grid burdens, and driving patterns compound to produce significant regional heterogeneity in the GHG benefits of electrification. We show that lightweighting further accentuates these regional differences. In fact, for the midsized cars considered in our analysis, model results suggest that aluminum lightweight vehicles with a combustion engine would have similar emissions to hybrid electric vehicles (HEVs) in about 25% of the counties in the US and lower than battery electric vehicles (BEVs) in 20% of counties. The results highlight the need for a portfolio of fuel efficient offerings to recognize the heterogeneity of regional climate, electric grid burdens, and driving patterns.

“…The review of lightweighting by Lutsey ignored negative aspects of lightweighting electric vehicles. Gearhart provided a review of vehicle emission reduction technologies including different automotive materials (high strength steel, aluminum, magnesium, and carbon fiber) and powertrains (internal combustion engine vehicles (ICEV), hybrid electric vehicles (HEV), fuel cell electric vehicles (FCEV) and battery electric vehicles) but did not mention any interactions. Kim and Wallington conducted a review of the impact of lightweighting on life cycle GHG emissions but explicitly excluded analyses of different powertrains due to the dominance of internal combustion engine vehicle analyses in the literature.…”

Section: Introductionmentioning

confidence: 99%

Review of the Fuel Saving, Life Cycle GHG Emission, and Ownership Cost Impacts of Lightweighting Vehicles with Different Powertrains

Luk

Kim

Kleine

et al. 2017

The literature analyzing the fuel saving, life cycle greenhouse gas (GHG) emission, and ownership cost impacts of lightweighting vehicles with different powertrains is reviewed. Vehicles with lower powertrain efficiencies have higher fuel consumption. Thus, fuel savings from lightweighting internal combustion engine vehicles can be higher than those of hybrid electric and battery electric vehicles. However, the impact of fuel savings on life cycle costs and GHG emissions depends on fuel prices, fuel carbon intensities and fuel storage requirements. Battery electric vehicle fuel savings enable reduction of battery size without sacrificing driving range. This reduces the battery production cost and mass, the latter results in further fuel savings. The carbon intensity of electricity varies widely and is a major source of uncertainty when evaluating the benefits of fuel savings. Hybrid electric vehicles use gasoline more efficiently than internal combustion engine vehicles and do not require large plug-in batteries. Therefore, the benefits of lightweighting depend on the vehicle powertrain. We discuss the value proposition of the use of lightweight materials and alternative powertrains. Future assessments of the benefits of vehicle lightweighting should capture the unique characteristics of emerging vehicle powertrains.