Findings

Driving away EV doubts

Electric vehicles reduce carbon footprints--even when the whole supply chain is taken into account.

Mark Alden Branch ’86

Mark Alden Branch ’86

Electric vehicle charging stations in Hamden, Connecticut. View full image

Worldwide, transportation is among the largest consumers of energy and the most significant producer of CO2 emissions, with the main culprit being light-duty vehicles—mostly passenger cars. To curb those emissions, many nations, including the US, are investing billions of dollars in promoting electric vehicles (EVs).  

Consumer demand for EVs is increasing. But is that electric vehicle you’re eyeing really going to reduce your carbon footprint? Critics cite the emissions released in the process of building EVs, such as excavating the necessary metals and producing the plastics.

Even so: the answer, says a team from the Yale School of the Environment, is yes.

For a paper in Nature Communications, the researchers studied carbon pricing, assessed the vehicles’ life cycles, modeled energy systems, and more. “There have been concerns that the electric vehicle supply chain, including the mining and processing of raw materials and the manufacturing of batteries, is far from clean,” says economics professor Kenneth Gillingham. “What we found is that—in addition to the pollution produced from tailpipe emissions by gasoline-powered vehicles—the fossil fuel supply chain is also dirty.” As technology continues to decarbonize the electricity supply, the EV supply chain will become even cleaner.

Another environmental concern is disposal of the lithium-ion batteries used by most EVs. But here too, electric vehicles come out cleaner when compared with factors such as leaking oil wells and the disposal of gasoline-powered car parts. Also, notes postdoctoral fellow Stephanie Weber ’21PhD, “We are seeing options for handling batteries, from developing more effective recycling methods to incorporating them into power-storage grids.”

As the electricity supply continues to decarbonize, says Gillingham, “large-scale adoption of electric vehicles can reduce CO2 emissions in more ways than we previously expected.”  

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