The Chevy Volt gives the phrase “pay to pollute” a whole new meaning.
General Motors pitches the pricey Chevy Volt as a means of reducing carbon emissions. The Volt web page states:
Electricity – a more sensible primary fuel
Put simply, electricity is a cleaner source of power. And as technology improves in the generation of electricity, we will continue to see reduced carbon outputs. Advancements in electricity production along with reduction in emissions from electric-powered driving could help make our world a cleaner place.
So does the Chevy Volt’s battery actually reduce carbon emissions? Here’s our analysis.
According to the EPA the 4-seat Volt is capable of driving 35 miles on its 16 kilowatt hours (kWh) of stored electric charge. The Volt’s gas-only fuel economy rating is 37 mpg.
Since two oxygen atoms from the atmosphere combine with each carbon atom when gasoline is burned, a gallon of gas produces about 19.6 lbs. of carbon dioxide (CO2) when burned. So when operating on gasoline, the Volt produces 0.53 lbs. of CO2 per mile (19.6 lbs. of CO2 per gallon divided by 37 miles per gallon).
Since we can’t quantify accurately just how much transmission loss there is between electricity generation and charging points, we’ll assume an impossible 100 percent efficiency at the charger to work out the CO2 emissions for the Volt’s 16 kWh stored charge.
In 2007, national “average” CO2 emissions were 2.16 lbs per kWh from coal-fired generation and 1.01 lbs per kW for gas-fired generation. according to Power Systems Analysis. Given that 44.46 percent of electricity in the U.S. is coal-fired and 23.31 percent is gas-fired, on a national basis, then, the mean emission of CO2 per kWh is 1.2 lbs/kWh. (2.16 lbs/kWh x 0.4446 = 0.96 lbs/kWh from coal, plus 1.01 lbs/kWh x 0.2331 = 0.24 lbs/kWh from gas).
The Volt’s “emissions mileage” from its stored charge is then 16 kWh x 1.2 lbs/kWh divided by 35 MPG = 0.55 lb CO2/mile.
So on an “average” basis, the Volt emits more CO2 from battery use than from gasoline use (0.55 lbs/mile vs. 0.53 lbs/mile).
Maybe you don’t think that’s a big difference, but the difference becomes more pronounced when the Volt is charged in states that rely more on coal-fired electricity.
In West Virginia where coal fires 96 percent of the state’s power, the Volt’s per mile CO2 emissions reach 0.95 lbs per mile. In Ohio, Volts emit about 0.84 lbs of CO2 per mile — much higher than the gasoline-powered rate of 0.53 lbs. per mile.
In fact, coal is burned to produce 44 percent or more of the electricity in 26 states (AR, CO, DE, GA, IA, IL, IN, KS, KY, MD, MI, MN, MO, MT, NC, ND, NE, NM, OH, OK, PA, TN, UT, WI, WV, WY). So, on average, Volts charged in those states will emit more CO2 from battery use than gasoline use.
Last November, the Nature Conservancy proclaimed:
CHEVY VOLT COULD DECELERATE AMERICA’S CARBON FOOTPRINT
Too bad it didn’t check under the hood.
The Chevy Volt, un-greenwashed
Brad,
I said “one of the greatest achievements” , and by the way, I like your list. I think that if someone had told me a few years ago that GM (of all companies!) would produce a car that would, in normal use, double the energy economy of the best cars from all over the world, and that it could be your only car no matter how far you wanted to drive, I wouldn’t have believed it. SAE just named it the best engineered car, and it has won virtually every automotive award you can name. The control system in the volt contains more than 8 million lines of code, more than the Boeing Dreamliner, and what is most amazing, is how seamlessly it all works. And when I think that the engineering team stuck with this project through a bankruptcy filing and untold questions about the future of GM, I am truly amazed.
One more thing. People seem to hate the Volt because Obama saved GM, and GM produced the Volt. This kind of thinking is just irrational.
I rode in a Volt at a press event in Brooklyn, MI last November. The car’s fit and finish is sub-standard. Neither was I impressed with the cheap interior. It reminded me more of a Dodge Neon in material and finish. The car has no pizazz! It’s not going to sell. Trust me… I know what I’m talking about. I’ve been in this business for years. Referring to my last post regarding market driven success stories, you cannot mandate an alternative ANYTHING in my part of the country, and I’m sure there are a majority of folks who’ll stand shoulder to shoulder with me.This has little to do with choosing sides. Common sense isn’t limited to the left or the right. I simply don’t believe the Volt is the efficient little wheeled wonder that you have suggested. Only time will prove its marketability.
This is the last time I will comment on this site. I posted because the original analysis of the Volt in this blog is simply wrong. I own a Volt, and I have seen what it can do. Fit and finish is at least as good as my Prius, and performance is much better overall. I don’t know if the car will be a commercial success for GM (probably not if they can’t get the price lowered), but that was not my point. I do know that of the 2,000,000 Priuses that have been sold, half have been sold in the last couple of years, and the Prius is not cheap and Toyota lost money on every one they sold for the first few years. That car turned out to be a big winner for them, but whether the Volt will be a similar success will depend upon many factors including cost reductions, reliability, etc.
And by the way, no one is mandating that anyone buy a Volt. There is a tax credit incentive, just like there was in the first few years on Prius sales, but that incentive has been offered on fuel efficient cars under both Republican and Democratic administrations in an effort to reduce our dependence on foreign oil. All I am saying is that when opinions are not supported by the facts, we should disavow them.
your calculations of co2 for the volt on electric is wrong! I own a volt and I average about 38 miles on 10 kwh, not 16 as you used. that calculates to about .32. not .55.