Combustion engine supply chain emissions are far worse than those for electric vehicles (EVs), despite concerns from analysts that indirect emissions from EV production could nullify their environmental benefits, a new report concludes.
“The surprising element was how much lower the emissions of electric vehicles were,” post-doctoral associate and study co-author Stephanie Weber told PVBuzz Media. “The supply chain for combustion vehicles is just so dirty that electric vehicles can’t surpass them, even when you factor in indirect emissions.”
Transportation is the world’s largest source of carbon dioxide in the atmosphere, responsible for nearly a quarter of global emissions. To cut back the greenhouse gases emitted by personal and light commercial vehicles, governments like the United States are investing heavily in a large-scale transition to EVs. However, some analysts “have cautioned that [large-scale EV adoption] can come with increased indirect emissions from electricity and battery production that are not commonly regulated by transport policies,” says the study in the journal Nature Communications.
The researchers used energy modelling and life cycle assessment to compare different emissions policy scenarios and decarbonization strategies. They found that supply chain as well as tailpipe emissions are lower for EVs. “The elephant in the room is the supply chain of fossil fuel-powered vehicles, not that of electric vehicles,” said lead author Paul Wolfram, adding that the faster drivers switch to EVs, the better—at least in countries like the U.S., where the electricity supply is sufficiently decarbonized.
To cost out the real carbon benefits, transportation emissions policy should be broadened to regulate all sources of vehicle emissions along the supply chain, the researchers suggest. Furthermore, nations with suitable low–carbon electricity grids can implement EV policy most effectively by backing battery EVs, but hydrogen fuel cell vehicles could become a viable alternative when the technology is more cost-competitive. The researchers say future research should consider the impacts of new technologies like carbon capture and storage at fuel refineries, as well as regional variations.