Effect of regional grid mix, driving patterns and climate on the comparative carbon footprint of gasoline and plug-in electric vehicles in the United States

Abstract

We compare life cycle greenhouse gas (GHG) emissions from several light-duty passenger gasoline and plug-in electric vehicles (PEVs) across US counties by accounting for regional differences due to marginal grid mix, ambient temperature, patterns of vehicle miles traveled (VMT), and driving conditions (city versus highway). We find that PEVs can have larger or smaller carbon footprints than gasoline vehicles, depending on these regional factors and the specific vehicle models being compared. The Nissan Leaf battery electric vehicle has a smaller carbon footprint than the most efficient gasoline vehicle (the Toyota Prius) in the urban counties of California, Texas and Florida, whereas the Prius has a smaller carbon footprint in the Midwest and the South. The Leaf is lower emitting than the Mazda 3 conventional gasoline vehicle in most urban counties, but the Mazda 3 is lower emitting in rural Midwest counties. The Chevrolet Volt plug-in hybrid electric vehicle has a larger carbon footprint than the Prius throughout the continental US, though the Volt has a smaller carbon footprint than the Mazda 3 in many urban counties. Regional grid mix, temperature, driving conditions, and vehicle model all have substantial implications for identifying which technology has the lowest carbon footprint, whereas regional patterns of VMT have a much smaller effect. Given the variation in relative GHG implications, it is unlikely that blunt policy instruments that favor specific technology categories can ensure emission reductions universally.

Electricity Generation in LCA of Electric Vehicles: A Review

“…They require few data and calculation time compared to models [85] They are not suitable to capture significant changes (infrastructural changes, fuel price, energy policies, changes to the grid due to economic conditions or other factors, generator or transmission additions) [43,85].…”

Alternative-fuel-vehicle policy interactions increase U.S. greenhouse gas emissions

“…No existing vehicle model in the 2015 Fuel Economy Datafile has a lower factor increase than 1.17 or a higher factor increase than 1.51. The location-related marginal emission factors for electric vehicles is important to accurately assess emissions from electric vehicles, and we adopt a range of estimates for regional marginal electricity grid emission factors summarized in Table S8 in the SI, wide enough to capture estimates from multiple studies, regions, seasons, and charge timing assumptions (Holland, Mansur, Muller, & Yates, 2016;Tamayao, Michalek, Hendrickson, & Azevedo, 2015;Yuksel, Tamayao, Hendrickson, Azevedo, & Michalek, 2016;Archsmith, Kendall, & Rapson, 2015). We use marginal generation mix estimates together with estimates of emissions for feedstock production emissions for coal and natural gas to produce a range of life cycle estimates associated with marginal electricity consumption (see Table S8).…”

Solar PV as a mitigation strategy for the US education sector

“…In SM section F, we provide a [43]. These estimates are produced by our research group using an approach similar to the one described in Siler-Evans et al [44,45] and used in the literature to assess the emissions and damages consequences from renewables, energy efficiency, and storage [11,[46][47][48][49][50][51]. Marginal damages reported on this website are marginal emissions reductions that are translated to damage reductions using two integrated air quality models: AP2 and EASIUR [29,45,52].…”