Study Examines Trade-Off between Decarbonization and Air Pollution Mitigation

The changeover to electric vehicles must be reflected by the growth of clean energy grids to reduce air pollution and mitigate climate change.

That is the major finding of a new study carried out by scientists from the Lawrence Berkeley National Laboratory, California, and Stanford University, California.

The study was recently published in the IOP Publishing journal Environmental Research Letters and investigates the most useful vehicle fuel technology for transportation in the United States, as well as the trade-off between the reduction in air pollution (health) and decarbonization (climate).

The transportation sector is the largest contributor to CO₂ emissions in the United States. Its impact on health and the environment is also significant. Greenhouse gases and criteria air pollutants affect different places in different ways.

Inês M.L. Azevedo, Study Co-Author and Professor, Stanford University

Azevedo continued, “Greenhouse gases disperse globally, stay in the atmosphere for decades to centuries, and their effects differ globally, but such an effect does not depend on where the emissions originate. Criteria pollutants have much shorter lifespans, and their effects depend on where the emissions occur.”

The study predicted the life cycle monetized damages caused by greenhouse gas emissions and criteria air pollutant emissions for transit buses, SUVs, and passenger cars in the United States.

Vehicles powered by four different kinds of fuel—grid electricity, CNG, diesel, and gasoline—coupled with three vehicle technologies (battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and internal combustion engine vehicles (ICEVs)) were taken into account.

Marginal damage method was utilized to evaluate climate change monetized damages related to greenhouse gases (N₂O, CH₄, CO₂) and health and environmental monetized damages due to criteria air pollutants (CO, NO_x, SO₂, VOCs, and PM2.5).

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.

Dr Fan Tong, Study Co-Author, Lawrence Berkley National Laboratory

Tong continued, “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.

Dr Fan Tong, Study Co-Author, Lawrence Berkley National Laboratory

“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,” added Tong.