A new study examining the life-cycle impacts of electric vehicles looks at global warming emissions and other environmental impacts from the production and use of vehicles in the European Union. Here’s one media story about the report with a rather damning headline – Study: ‘Global Warming Potential’ From Electric Cars Twice That Of Conventional. Kind of reminds me of some of the coverage of our State of Charge report (See a Columbia Journalism Review blog on that). It’s stories like this that might lead some casual readers to conclude that electric vehicles are a disaster.
But not so fast….
After reading the study, I found that while some portions of the analysis were surprising, the basic conclusions are not entirely new.
(1) EVs offer global warming benefits today (20-24% on today’s electricity mix in the EU compared to a gasoline vehicle, according to the authors’ assumptions), but the greatest global warming benefits occur when EVs are paired with cleaner sources of electricity, such as renewables.
(2) The manufacturing impacts of EVs are greater than those of conventional gasoline vehicles primarily because of battery production. These impacts need to be addressed through the use of greater material recycling and other measures. (The study does find that manufacturing an EV results in twice as many global warming emissions as a conventional vehicle – which IS surprising. More on that below.)
The impacts of current vehicle production and use are important, but this is only one part of the story when evaluating alternative vehicles and fuels. It’s also critical to understand the potential for reducing those impacts over time. EVs, or any other promising alternatives to the internal combustion engine, shouldn’t be dismissed based solely on an assessment of current vehicle production processes and fuel production (grid electricity in this case). Otherwise we are likely to be tethered exclusively to the gas pump for decades to come.
And misleading media coverage of science journal articles certainly doesn’t advance the conversation.
Now on to some of the substance.
If the emissions of producing an EV are really twice as high as a gasoline vehicle, what does that do to the global warming benefits of EVs?
One finding of the study that caught my attention was the estimate that global warming emissions of EV production are twice that of a conventional gasoline vehicle. I’ve addressed global warming emissions of EVs in a number of previous blog posts and in our State of Charge analysis, but I’ve focused on the emissions from plugging-in, not vehicle manufacturing.
I ran a quick comparison using two sources on vehicle manufacturing emissions. The two sources are the Argonne National Labs GREET2012 model, which shows EV production emissions are 33% higher than a comparable gasoline model, and the new study results from Hawkins et al., which estimate that EV production emissions are closer to double (200%) those of a conventional vehicle.
The figure below shows the reduction in global warming emissions compared to a 27 mile-per-gallon gasoline vehicle – which is the average efficiency of new compact cars sold in the US.
The columns on the far left show the State of Charge results without accounting for vehicle manufacturing; an EV results in a 98% drop in global warming emissions when charged exclusively with solar power, a 77% drop when charged on the cleanest US regional electricity grid, and a 19% drop in when charged on the dirtiest US regional electricity grid region.
The second and third set of columns add in the estimates of vehicle manufacturing emissions from GREET2012 and Hawkins et al. respectively.
The numbers show that even in the worst case, on the dirtiest grid and assuming EV vehicle production creates twice the number of global warming emissions as a gasoline vehicle, an EV still has a slight (6%) emission advantage compared to the average new compact.
If the worst case represented the full potential of electric vehicles to reduce global warming emissions, pursuing EVs as part of our solution to oil use and climate change would certainly be questionable. But it doesn’t. Even today’s cleaner electricity grids provide substantial benefits and renewables like solar are even better.
By better understanding the impacts of vehicle production we can identify opportunities to reduce them. The authors of the new study suggest as a first step focusing on recycling of materials and increasing the life of electric vehicles (the longer they last, the better). That seems like sage advice to me.
We also need to keep up our effort to increase renewable electricity production and move away from high-emission sources like coal. A cleaner grid will enable lower-emission electric vehicles in the future.
And for those not willing to wait (including the 39% of California EV owners with rooftop solar), powering an EV with clean renewable energy is, in fact, an option available today.
About the author: Don Anair is an engineer with expertise on diesel, hybrid and battery electric vehicle, and goods movement technologies and the policies needed to turn them into real solutions for U.S. oil dependence, air pollution and global warming. He holds a master’s degree in electrical engineering.