Navigant Research Blog

Are EVs Really Green?

Dave Hurst — July 29, 2013

In a recent article in IEEE’s Spectrum magazine, “Unclean at any Speed,” Ozzie Zehner argues that battery electric vehicles (BEVs) are essentially trading one environmental problem for another rather than moving the ball forward on clean transportation.  He makes a compelling case by arguing that the greenhouse gas (GHG) cost of electricity generation is too high, the production of BEVs is worse than gasoline vehicles, and that any personal automobile is ultimately worse for the environment than public transit.  I believe he falls short of proving his point because, as with many of these types of articles, he either misses or cherry picks some key facts from a number of studies.

The first is that the production of gasoline and diesel is very energy intensive and ultimately shares almost all the same attributes as electricity production, except with additional emissions.  This process does not include potential problems with transporting the fuel, which is largely a land use issue for electricity.  However, it is very difficult to compare the emissions of electricity production and gasoline or diesel production for vehicle usage.  According to Argonne National Lab’s GREET model, reformulated low-sulfur gasoline production releases 2.3 kg of GHG emissions per gallon produced, which equates to about 82 grams per mile (g/m) in a Ford Focus, which combined with its tailpipe emissions would bring the car to a total of 351 g/m (though the GREET model places its passenger car emissions at 453.1 g/m).  Distributed electricity (using the U.S. average for electricity production) produces 876.9 grams of GHG emissions per kWh.  Assuming these GHG emissions are directly attributed to an electric passenger car, this translates into 312.8 g/m according to the GREET model.  Granted, there are a lot of different ways to look at this and, depending on the source of electricity, the type of gasoline produced, and the car’s fuel economy, one can create a model in which an electric vehicle pollutes more on a per mile basis than a comparable gasoline vehicle.

Forward Motion

Zehner’s second point is that BEVs are much more energy intensive to produce.  The question of production is an interesting one, but again the article sidesteps important considerations.  To be clear, vehicle production, whether BEVs or gasoline powered, is a very energy intensive process.  Much of the materials used in vehicles are recycled, including the aluminum and other metals mentioned in the article, and these materials are being used in all types of vehicles.  Assuming that we want to build gas-powered vehicles that use less gasoline, it is pretty easy to anticipate an increase in lightweight materials such as aluminum.

Battery and electric motor research is also not standing still.  The first generation of automobiles was certainly more polluting than the current generation.  The question is not whether BEVs are the panacea for all of the automaker’s environmental ills, but rather whether this is a step in the right direction.  Mining operations for lithium are sure to get a boost from electric vehicle production (as did nickel before it), but according to research publicized by the IEEE from the Swiss Federal Laboratories for Materials Science and Technology, the environmental cost of this is much lower than the production of gasoline engines.

Change is Coming

And this brings us to the one point that I do totally agree with Zehner on:

“If legislators truly wish to reduce fossil-fuel dependence, they could prioritize the transition to pedestrian- and bike-friendly neighborhoods. That won’t be easy everywhere – even less so where the focus is on electric cars. Studies from the National Academies point to better land-use planning to reduce suburban sprawl and, most important, fuel taxes to reduce petroleum dependence.”

The best way to reduce the environmental impact of transportation is for everyone to stop using their own individual cars and trucks.  But Zehner seems to be saying, “Drive whatever you want today because these new transportation tools are not any better than the old ones, and to enact real change we have to fundamentally change transportation in America.”

BEVs are changing some of the transportation tools; new urban planning and reversing urban sprawl will fundamentally changes people’s lifestyle.

I am a bit more pragmatic and argue that based on what we know, the environmental benefits of BEVs outweigh the downsides.  People will change when they have a compelling reason to do so, and so far, the environmental impact of transportation has been an area for incremental (not dramatic) lifestyle changes.  A sky high gas tax could provide that compelling reason but remains politically untenable in most places.  However, for those hoping for dramatic changes, it appears patience may pay off as some of them are beginning to appear on the horizon.

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