When comparing electric vehicles (EVs) to gas-powered vehicles, most studies have focused on the electricity or fuel consumed while driving, and where those fuels come from. But a European study, published in the Journal of Industrial Ecology on October 4, provided a full lifecycle analysis that took into account not only the so-called “use phase,” but also the “production” (manufacturing) and “end-of-life” (disposal and recycling) phases. The results were dismaying.
The researchers found that in some ways, or in some circumstances, EVs are more polluting than gas-powered vehicles. But few reporters who covered the study explained those distinctions clearly, producing short stories that portrayed EVs as an unqualified “threat” to the environment instead.
What tripped up many reporters was the conclusion that while the majority of all vehicles’ “global warming potential” (i.e. direct or indirect greenhouse gas emissions) comes from their use phase, EVs produce twice the warming potential of gas-powered vehicles during the production phase. For instance, a CBS station in Connecticut reported that EVs produce twice the global-warming potential overall, but that’s not true. In fact, they usually counter the excesses of the production phase during the use phase—all the more so the longer they’re driven.
According to study, when powered by “average European electricity,” EVs have 20-24 percent less warming potential over their lifetime than gas-powered vehicles, and 12 percent less when powered by electricity made from natural gas. It’s only when powered by electricity from coal that EVs have 17-27 percent more warming potential. The conclusion that the “dirtiest” types of electricity erase EVs’ advantage is similar to one reached by the Union of Concerned Scientists back in April. But then, as now, gotcha-oriented coverage belied the fact that EVs are generally better than gas-powered vehicles where global warming is concerned. [Update: The author of the UCS’s April report wrote a helpful analysis of the European study that calculated that even when taking its conclusions about production into consideration, EVs are still a net positive for the climate.]
Many articles quoted lines in the European study where the researchers wrote, “It is counterproductive to promote EVs in areas where electricity is primarily produced from lignite, coal, or even heavy oil combustion … a more significant reduction in GWP could potentially be achieved by increasing fuel efficiency or shifting from gasoline to diesel….”
But few quoted the sentences that came next, which read:
Conversely, the combination of EVs with clean energy sources would potentially allow for drastic reductions of many transportation environmental impacts, especially in terms of climate change, air quality, and preservation of fossil fuels. The many potential advantages of EVs should therefore serve as a motivation for cleaning up regional electricity mixes…
The more troubling conclusion of the European study, which few reports explained well enough, had nothing to do with “warming potential.”
While EVs can lead to less land and air pollution (which occurs mostly during the use phase and depends on the energy mix), the researchers found that the production of EVs can lead to a lot more pollution than production of gas-powered vehicles, with higher potential for human toxicity, freshwater eco-toxicity, and freshwater eutrophication (nutrient runoff that creates harmful algal blooms). According to the researchers, these effects “stem mostly” from the disposal of the sulfide-rich waste produced by the mining of the extra copper and nickel that EVs need for their batteries.
That’s a significant concern and the researchers wisely counseled, in a section of their paper devoted to policy implications, that:
[A] promotion of EVs should be accompanied by stricter life cycle management and life cycle auditing. Considering how the potential problem shifts mostly arise from material requirements of EV production, effective recycling programs and improved EV lifetimes would constitute an appropriate first response.
Indeed, far from vilifying electric vehicles, the researchers seem to see potential for improvement, acknowledging that “EVs have only recently entered mass production, their ongoing development is still very much open-ended, and technologies and production processes are evolving rapidly.”
The Guardian’s Leo Hickman, who provided the most thorough and nuanced explanation of the study by far, came to a similar interpretation after consulting the researchers and multiple other sources. “The authors of this new paper are evidently not saying that electric cars are ‘bad’ for the environment in all circumstances,” he wrote, “but they are confirming what many already knew: that as electric cars become more popular” we must pay attention to their drawbacks.
Perhaps the researchers themselves put it best:
EVs offer advantages in terms of powertrain efficiency, maintenance requirements, and zero tailpipe emissions, the last of which contributes to reducing urban air pollution relative to conventional internal combustion engine vehicle. This has led to a general perception of EVs as an environmentally benign technology. The reality is more complex, requiring a more complete account of impacts throughout the vehicle’s life cycle.
If only that complexity wasn’t so consistently lost on the media.
Curtis Brainard writes on science and environment reporting. Follow him on Twitter @cbrainard.