New studies have revealed a potential unexpected effect of the electric vehicle shift in India and China, indicating that sulfur dioxide emissions could rise above current levels if these countries completely localize their electric vehicle supply chains. Most of these emissions would originate from the refinement and production of nickel and cobalt, which are crucial minerals for today’s electric vehicle batteries.
Although electric vehicles are essential to the global energy transition, recent research from Princeton University has shown that processing the vital minerals used in these batteries could lead to pollution hotspots around manufacturing centers.
By concentrating on China and India, the researchers discovered that sulfur dioxide (SO2) emissions could rise by as much as 20% from current levels if these countries were to completely localize their electric vehicle supply chains. The majority of these SO2 emissions would stem from the processing and manufacturing of nickel and cobalt—key minerals for modern electric vehicle batteries.
“Many discussions around electric vehicles tend to focus on reducing emissions from transportation and power generation,” remarked Wei Peng, the lead author and an assistant professor of public and international affairs at the Andlinger Center for Energy and the Environment. “However, our research indicates that the implications of electric vehicles extend beyond just tailpipe emissions or electricity usage; it’s also about the entire supply chain.”
In an article published in Environmental Science & Technology, the researchers emphasized that nations must take a thoughtful approach when constructing clean supply chains as they implement plans to reduce carbon emissions.
When it comes to battery production, the team highlighted the necessity of establishing and enforcing robust air quality standards to prevent the unintended effects associated with the electric vehicle transition. They also recommended exploring alternative battery chemistries to avoid the SO2 emissions linked to conventional battery manufacturing.
“Every clean energy technology has its own challenges and tradeoffs,” stated Anjali Sharma, the first author and a former postdoctoral researcher in Peng’s group, now an assistant professor at the Centre for Climate Studies and Ashank Desai Centre for Policy Studies at the Indian Institute of Technology, Bombay. “Recognizing these tradeoffs doesn’t imply halting the energy transition; rather, we must proactively address and mitigate them as much as possible.”
A tale of two countries
Both India and China have significant reasons to limit SO2 emissions, given that this compound contributes to fine particulate matter, which is linked to a range of cardiovascular and respiratory issues. These countries are already grappling with severe air pollution problems, with approximately 1.4 million premature deaths in China and around 1.7 million in India attributed to exposure to fine particulate matter in 2019.
However, the two nations are at different stages in terms of electric vehicle development. Peng explained that while China has a domestic electric vehicle supply chain firmly in place, India is still at the beginning of developing its own. This differential status enabled researchers to outline immediate priorities as both countries work on building their electric vehicle supply chains.
“China needs to figure out how to clean its existing supply chain, whereas India has the chance to create a more efficient supply chain from scratch,” stated Peng, who is also part of the Center for Policy Research on Energy and the Environment. “Each scenario presents its unique challenges and opportunities.”
For India, a key initial step would be to focus on reducing pollution in the power sector. This would entail implementing stringent SO2 controls for thermal power plants, utilizing established technologies such as flue-gas desulfurization. In contrast, China, which already adheres to strict emissions regulations in the power sector, needs to prioritize reducing SO2 emissions from battery production—an area still less understood.
Moreover, the researchers pointed out that neglecting emissions from battery production would be a critical mistake. In scenarios where both China and India completely localized their supply chains, prioritizing a cleaner power grid did little to mitigate SO2 emissions. Only by focusing on cleaning the battery manufacturing processes could they prevent the emergence of SO2 pollution hotspots.
“People often assume that transitioning to greener technologies will always yield beneficial outcomes for both climate and air quality,” noted Sharma. “However, if manufacturing emissions are overlooked, you might reduce carbon and nitrogen oxide emissions but inadvertently increase air pollution burdens for communities near production facilities.”
Human-centered approaches to decarbonization
While the analysis concentrated on China and India, the researchers argued that if pollution from battery manufacturing goes unaddressed, it will become an increasingly global issue as electric vehicle adoption grows. Sharma emphasized that even if countries like China and India were to outsource battery production, failing to have strategies in place for curbing SO2 emissions would merely shift the problem elsewhere.
“It’s crucial to analyze electric vehicles from a global supply chain perspective,” Sharma stated. “Regardless of whether India opts to establish a domestic supply chain or imports batteries, the pollution problem won’t disappear; it will simply be transferred to another country.”
Alongside advocating for proactive air pollution standards at national or local levels, the researchers also explored how altering battery chemistry in electric vehicles could help reduce SO2 emissions on a broader scale.
Presently, most electric vehicle batteries depend on cobalt and nickel, but the emergence of alternative chemistries involving iron and phosphate (known as lithium iron phosphate batteries) could mitigate some concerns linked to the extraction and processing of cobalt and nickel. By avoiding these two minerals, scenarios with widespread use of lithium phosphate batteries showed significantly reduced SO2 emissions from production.
Ultimately, Peng highlighted the importance of keeping human impact at the forefront when planning decarbonization initiatives, as even the most promising technologies can lead to unintentional consequences.
“We understand a lot about the crucial technologies for cutting carbon emissions,” noted Peng. “However, it’s equally important to assess how these technologies will impact people. My focus is on identifying the best ways for technologies to harmoniously coexist with societal needs, as such strategies will yield the most favorable outcomes for the greatest number of individuals.”
