How Green Is An Electric Car?
Electric cars have been hailed as the clean energy solution to personal transportation demands. The technology has come a long way in just a few years, and already there are thousands of plug-in vehicles gliding silently through our city streets.
A new study out of Norway challenges the claim that these cars are truly “green,” however. It’s true that there aren’t any emissions coming out of the tailpipe, but that’s not the only way personal vehicles impact the environment. The research, published recently in the Journal of Industrial Ecology, concludes that our push for widespread EV adoption might be premature, and that the electric car is just a trade-in of an old set of pollution problems for new ones.
While they acknowledge that the electric car is an important (and long overdue) technological innovation, the researchers say that its life cycle — from creation to disposal — isn’t that much better than its fossil-fueled counterparts. In the Norwegian study, titled “Comparative Environmental Life Cycle Assessment of Conventional and Electric Vehicles,” the authors looked at conventional and electric vehicles to see how all phases, from production to use to dismantling, affect the environment. Here’s what they found:
EVs powered by the present European electricity mix offer a 10% to 24% decrease in global warming potential (GWP) relative to conventional diesel or gasoline vehicles assuming lifetimes of 150,000 km [93,205 miles]. However, EVs exhibit the potential for significant increases in human toxicity, freshwater eco-toxicity, freshwater eutrophication [introduction of excess nutrients that stimulate abnormal plant growth], and metal depletion impacts, largely emanating from the vehicle supply chain. Results are sensitive to assumptions regarding electricity source, use phase energy consumption, vehicle lifetime, and battery replacement schedules. Because production impacts are more significant for EVs than conventional vehicles, assuming a vehicle lifetime of 200,000 km exaggerates the GWP benefits of EVs to 27% to 29% relative to gasoline vehicles or 17% to 20% relative to diesel. An assumption of 100,000 km decreases the benefit of EVs to 9% to 14% with respect to gasoline vehicles and results in impacts indistinguishable from those of a diesel vehicle.
“Although EVs are an important technological breakthrough with substantial potential environmental benefits, these cannot be harnessed everywhere and in every condition,” the researchers conclude. “Our results clearly indicate that it is counterproductive to promote EVs in areas where electricity is primarily produced from lignite, coal, or even heavy oil combustion.”
This same point has been made by those who resent the auto industry’s tendency to bill the EV as a zero-emission car. While the completed car may not emit toxic fumes, they are most certainly emitted in the production process. And then there’s the problem of charging. Unless you generate the bulk of your own electricity through solar, wind or geothermal (or purchase power from a utility that does) it’s coming from coal, gas or nuclear power plants. Instead of reducing the demand for fossil fuels, the rush to embrace EVs might actually be keeping these industries in business.
However, as EV owners and clean tech companies are quick to point out, electric vehicles give you the opportunity to power your car with renewable energy, while combustion engine vehicles do not. We’ve seen several solar companies debut charging stations that are powered by the sun, while just as fast and powerful as traditional stations. If you’re interested in calculating potential cost vs. benefit of bundling solar arrays and electric cars together, check out the recently unveiled WattPeople app.
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