The Car Battery's Carbon Footprint

Lithium-ion battery pack for 2011 Chevrolet Volt

Lithium-ion battery pack for 2011 Chevrolet Volt

Electric cars may run clean. But how green is the battery?

Hi, this is Steven Cherry for IEEE Spectrum's "This Week in Technology."

With governments around the world investing heavily in electric and hybrid cars, the demand for the batteries that power these vehicles is on the rise. The United States alone has invested $2.4 billion to ramp up production, and the first wave of lithium-ion car batteries is just now hitting the market.

By 2014, the U.S. could be making a half million batteries a year. Battery-powered cars emit fewer pollutants and greenhouse gases. That's the point.

But some critics have wondered: Just how green are the batteries themselves? Where does that soft silvery metal, lithium, come from? What goes into making it into a battery? And just what is its impact compared to that of a traditional combustion engine?

My guest today is Dominic Notter, a researcher for the Swiss Federal Laboratories for Materials Science and Technology. He joins us by phone from his office in Duebendorf, Switzerland. Dominic, welcome to the podcast.

Dominic Notter: You're welcome.

Steven Cherry: So maybe you can tell us what your research found: How green is a lithium-ion battery, and how does that compare to a regular combustion engine?

Dominic Notter: I can't tell you how green it is, because it did not compare different batteries, but I can tell you that the battery car is greener than the internal combustion engine car. If you look at climate change, it is most interesting for most people nowadays: The battery electric car is 30 to 40 percent greener than the standard car.

Steven Cherry: If I understand your research correctly, there were some things to be said about the environmental consequences of mining the lithium and processing it and turning it into a car battery, but that turned out to be just a very small fraction of the entire environmental footprint of a battery-driven car. Is that correct?

Dominic Notter: That's correct. That's one of the nine findings of our study, is that the impact of the lithium battery used in these cars is very small. The operation phase of the car is the dominant contributor to the environmental burden caused by the transport service. So that means that charging the battery with electricity is much, much more important than the contribution of the lithium within the battery. The contribution of the lithium within the battery has the share of about 2 percent to the transport service.

Steven Cherry: And I guess it makes a big difference where the electricity for the car comes from.

Dominic Notter: That's true. For the comparison of the electric car and standard car, we used European electricity mixed for charging the battery of the electric car. European electricity mix consists of about 51 percent on fossils and about 30 percent nuclear and 10 percent hydro, and the rest is a very small renewable share.

Steven Cherry: I understand it wasn't so easy to collect all the data involved in your study.

Dominic Notter: Yes, this is the big issue when you're doing life-cycle assessment. So, life-cycle assessment, you have to do mainly two steps. One of them is describe which emissions will occur and which raw materials are used during the life of the product. These are usually when we did the LCI, the life-cycle inventory of this battery.

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Comments (5)
  1. I should add to this article that even when it comes to electric grid emissions, the US electric grid is about as dirty as a Prius when you are charging an equivalent electric car from an "average" charging point in the US grid.
    My research in the past has indicated that the electric car would be less resource burden to make, and at least as clean as the cleanest cars today to charge, even in the US which is one of the dirtiest grids in the developed world (second only to china, which isn't all that much dirtier).
    Seeing as I'm Canadian, my research has also shown that the Canadian grid is about 4x more efficient in terms of CO2 emissions and overall GHG contribution to any atmospheric warming. there are also provinces in Canada that are fully renewable. A resident of Manitoba driving an electric car for example would not contribute to climate change at all (with the exception to the "cradle" --manufacturing-- pollution).

  2. @Chris: Your conclusion is slightly off but headed in the right direction. A 50-MPG Prius has a slightly lower wells-to-wheels carbon burden burning gasoline than the dirtiest grids in the U.S., but to equal the *average* U.S. grid gets you up to 70 or 80 MPG, and to equal California's (where many early EVs will be sold) you need to go even higher. See EPRI-NRDC study from July 2007 for backing data.

  3. Now do a study on the carbon footprint of oil. Don't forget recent spills.

  4. @CDspeed: Properly constructed "wells-to-wheels" studies of carbon footprint do include all parts of the oil process, including the carbon from refining and transporting the various petroleum distillates. Must admit I don't know, however, if oil SPILLS and their carbon footprint are taken into account.

  5. hi this is a great argument and has helped me with my next blog. i cant help feeling though that the people who run our countries are charging ahead too fast especially with the dirty electricity that we are producing, its the cart before the horse in my opinium eric roberts

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