Study: EVs 3 Times More Polluting than Gas Cars in Some States

by David Iaconangelo (E&E News) The grid may still be too coal-heavy in some parts of the United States for electric vehicles to be a better option for local air quality than gas cars, according to an analysis published yesterday by scientists at Lawrence Berkeley National Laboratory and Stanford University. READ MORE

Excerpt from Institute of Physics/Phys.Org): Any uptake in electric vehicle use must be mirrored by the development of clean energy grids to mitigate both climate change and air pollution.

That is the key finding of a new study by researchers at the Lawrence Berkeley National Laboratory, California, and Stanford University, California.

Published today in the IOP Publishing journal Environmental Research Letters, the study examined the most beneficial vehicle fuel technology for transportation in the US, and the trade-off between decarbonization (climate) and air pollution (health) mitigation.

The study estimated the life cycle monetized damages from greenhouse gas emissions and criteria air pollutant emissions for passenger cars, SUVs, and transit buses in the US. It looked at vehicles powered by four different fuel types—gasoline, diesel, CNG, and grid electricity—paired with three vehicle technologies: internal combustion engine vehicles (ICEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs).

It used a marginal damage approach to estimate climate change monetized damages associated with greenhouse gases (CO₂, CH₄, N₂O) and health and environmental monetized damages caused by criteria air pollutants (SO₂, NO_x, CO, PM2.5, and VOCs).

Co-author Dr. Fan Tong, from the Lawrence Berkley National Laboratory, said: "We found vehicle electrification has substantial potential to reduce climate change damages and air pollution damages. With the 2014 electricity grid, vehicle electrification can already reduce climate change damages compared to conventional petroleum vehicles on the west coast and New England."

"However, in some locations, battery-electric vehicles can lead to much higher air pollution damages than conventional gasoline/diesel vehicles. This occurs in regions where coal is still prevalent (such as Midwest and Southeast)."

"Even in US regions with relatively clean electricity grids (such as the west coast and New England), battery electric vehicles can only partially reduce air pollution damages. Our results highlight the importance of continually cleaning and decarbonizing electricity grids, such as with increased amounts of renewable energy technologies and nuclear power, as well as improving vehicle efficiency. A clean electricity grid with near-zero emissions not only benefits the electricity sector and traditional electricity consumers such as buildings but also becomes increasingly crucial for a sustainable transportation future." READ MORE

Abstract from Environmental Research Letters: The transportation sector is the largest contributor to CO₂ emissions and a major source of criteria air pollutants in the United States. The impact of climate change and that of air pollution differ in space and time, but spatially-explicit, systematic evaluations of the effectiveness of alternative fuels and advanced vehicle technologies in mitigating both climate change and air pollution are lacking. In this work, we estimate the life cycle monetized damages due to greenhouse gas emissions and criteria air pollutant emissions for different types of passenger-moving vehicles in the United States. We find substantial spatial variability in the monetized damages for all fuel-vehicle technologies studied. None of the fuel-vehicle technologies leads simultaneously to the lowest climate change damages and the lowest air pollution damages across all U.S. counties. Instead, the fuel-vehicle technology that best mitigates climate change in one region is different from that for the best air quality (i.e. the trade-off between decarbonization and air pollution mitigation). For example, for the state of Pennsylvania, battery-electric cars lead to the lowest population-weighted-average climate change damages (a climate change damage of 0.87 cent/mile and an air pollution damage of 1.71 cent/mile). In contrast, gasoline hybrid-electric cars lead to the lowest population-weighted-average air pollution damages (a climate change damage of 0.92 cent/mile and an air pollution damage of 0.77 cent/mile). Vehicle electrification has great potential to reduce climate change damages but may increase air pollution damages substantially in regions with high shares of coal-fired power plants compared to conventional vehicles. However, clean electricity grid could help battery electric vehicles to achieve low damages in both climate change and air pollution. READ MORE