Graphic: What’s a Vehicle’s Carbon Footprint?

I recently took a test-drive in a Tesla Model 3. It was an impressive car, but the ride left me wondering: with all the electric horsepower under the hood, was it really better than a hybrid?

2019 Nissan Leaf

2019 Nissan Leaf. Photo: Nissan

The EPA has a dated, but functional website with all the fuel economy and energy efficiency information a driver could want on gasoline, hybrid, and electric vehicles. The EPA also has a unit of measure for electric vehicles called “MPGe”, an energy efficiency metric introduced in 2010 to compare the amount of energy consumed by alternative fuel vehicles to gasoline ones. The ratings are based on a formula that assumes that 33.7 kilowatt-hours (121 megajoules) of electricity is equivalent to one gallon of gasoline.

Regardless of where you live, the laws of nature say that one gallon of gasoline will produce about 20 pounds of carbon. In Minnesota, however, Xcel Energy produces electricity emitting 0.857 pounds of CO2 per killowatt-hour of electricity produced (on average for 2018). Put those numbers another way, with Xcel, 23.3 kilowatt-hours (84.0 magajoules) of electricity is equivalent to one gallon of gasoline in terms of carbon emissions.

I created an easy chart for comparing the pounds of CO2 per mile travelled, using a combination of EPA estimates and the Xcel Energy emissions data. You can see any vehicle’s fuel or electric economy at FuelEconomy.gov.

To calculate carbon per mile for a gasoline or hybrid car, take the figure 20.35 pounds of carbon per gallon of gasoline and divide by your fuel economy in miles per gallon. For my vehicle, a 2015 Prius, 20.35 / 45 = 0.452 pounds per mile.

To calculate carbon per mile for an electric car, take the FuelEconomy.gov kilowatt-hours per 100 miles, divide by 100, and multiply by your local area’s average for pounds of CO2 per kilowatt-hour. In Minnesota, with Xcel Energy, this is 0.857 pounds of CO2 per killowatt-hour of electricity produced. For a 2019 Nissan Leaf, we would calculate 31 / 100 × 0.857 = 0.266 pounds of CO2 per mile.

For all chart data, there is a public Google Spreadsheet.

Carbon Emissions Of Select Vehicles

Carbon emissions of select vehicles. Graphic: Author

What wheels do you take around town? What steps do you take to reduce your carbon footprint? Share your adventures and your discoveries in the comments.

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15 Responses to Graphic: What’s a Vehicle’s Carbon Footprint?

  1. Mark September 6, 2019 at 12:35 pm #

    Time to order a Tesla

  2. Monte Castleman September 6, 2019 at 12:46 pm #

    Although there’s a lot of Jeep Grand Cherokees around, a comparison with more typical gas powered vehicles like SUV crossovers and mid-sized sedans would be interesting. Think Toyota RAV4, Honda CR-V, Toyota Camry, Honda Accord.

    Also range on any gas or hybrid vehicle is essentially unlimited since you can fill it to complete top at any gas station in 5 minutes

    • Jeff L. September 6, 2019 at 1:19 pm #

      The author purposely picked the most over-the-top model (Trackhawk) Grand Cherokee the instead of the mainstream model that accounts for 95% of all Jeep GC sales. Fairly certain most soccer moms aren’t driving around in a 707hp SUV.

      The article would definitely benefit from a more balanced approach that shows the most common vehicles on the road. I for one would be very interested in seeing that data.

  3. Bill Lindeke
    Bill Lindeke September 6, 2019 at 12:55 pm #

    The carbon footprint of a car has to include the carbon cost of producing the car (and disposing of it when it is obsolete). See this article from the UK (https://www.theguardian.com/environment/green-living-blog/2010/sep/23/carbon-footprint-new-car):

    “The best we can do is use so-called input-output analysis to break up the known total emissions of the world or a country into different industries and sectors, in the process taking account of how each industry consumes the goods and services of all the others. If we do this, and then divide by the total emissions of the auto industry by the total amount of money spent on new cars, we reach a footprint of 720kg CO2e per £1000 spent.

    Interestingly, the input-outpout analysis suggests that the gas and electricity used by the auto industry itself, including all the component manufacturers as well as the assembly plant, accounts for less than 12% of the total. The rest is spread across everything from metal extraction (33%), rubber manufacture (3%) and the manufacture of tools and machines (5%) through to business travel and stationary for car company employees.

    The upshot is that – despite common claims to contrary – the embodied emissions of a car typically rival the exhaust pipe emissions over its entire lifetime. Indeed, for each mile driven, the emissions from the manufacture of a top-of-the-range Land Rover Discovery that ends up being scrapped after 100,000 miles may be as much as four times higher than the tailpipe emissions of a Citroen C1.”

    • Janne September 7, 2019 at 8:59 am #

      Thank you, Bill.

  4. Jeff L. September 6, 2019 at 1:26 pm #

    Just to clarify, what you felt when driving the Tesla wasn’t horsepower, those numbers aren’t particularly impressive, it was the torque. The beauty of electric is that it generates maximum torque at 1rpm so that’s what you’re actually feeling.

  5. John Danielson September 6, 2019 at 8:08 pm #

    You are aware the a large percentage of Xcel’s electric is produced by nuclear energy?

    This only proves the need for more nuclear power plants. This is the cleanest and safest form of electrical generation.

    Call your congressmen and tell them to release the liberal ban on building new nuke plants!!!

    Electric cars, motorcycles and bikes are pretty cool.

  6. John Danielson September 7, 2019 at 6:21 am #

    I did forget the Japanese plant built on an earthquake fault. That was a brilliant idea wasn’t it. No issue will ever happen there.

  7. Julie Kosbab September 7, 2019 at 2:52 pm #

    Note: Several comments were removed for violation of comment policy, including “valid email address” and “name-calling.”

    Thanks.

  8. Richard Holst September 8, 2019 at 10:21 am #

    Another thing to consider is the cleanest a combustion vehicle will run is when it is brand new. It will slowly get worse over time as internals wear, leak, or your catalytic converter becomes less effective.

    Electric cars will become cleaner over time in most states such as Minnesota. Here we are continuously increasing our solar and especially wind produced energy.

    • Andrew Evans September 16, 2019 at 2:52 pm #

      That really depends though. Yes, cars do get worse as they age, however an electric car at some point will need the battery pack replaced. Which isn’t really all “that” expensive when considering what would have been spent in a similar gas vehicle, its’ just all at once vs yearly.

      So at that point it would depend on the environmental cost of building the new pack and recycling or disposing of the old one.

      Then too the environmental cost of that old vehicle would need to be weighed against replacing it. It very well could be better to keep using it with the bumped air pollution than what it all would take to build a new one – although the immediate environment would be taking the hit.

  9. donavannj September 16, 2019 at 5:27 pm #

    So, why specifically did you pick the racing spec version – and yes, it is the racing spec version – of the Grand Cherokee and not either the regular Grand Cherokee or even the Trailhawk? The racing spec version is obviously going to get garbage fuel economy even when compared to the standard version.

    • Andrew Evans September 19, 2019 at 8:10 am #

      I guess it’s pretty simple, if you don’t count the cost to manufacture a vehicle.

      1 gallon roughly, as per a extremely short google search, is 20lbs of Co2. Using that, and dividing by miles we can do the following. (20/mpg=C02 per mile)

      15mpg = 1.33
      20mpg = 1
      25mpg = .8
      30mpg = .666
      35mpg = .571
      40mpg = .5
      45mpg = .444
      50mpg = .4

      I’m not going to go too deep into this at the moment, but looking at another recent article here (Report: Electric and Plug-In Cars Have 21 Percent Fewer Lifetime Emissions Than Gas Ones) has the following. I’ll just keep it to ICE vs Electric.

      Standard Car/Vehicle is 5.6 tons of emissions to produce.
      Electric is 8.8 tons.

      The Electric car starts 3.2 tons in the hole and needs to make that up. I still want to know how much of that is in the battery, because at some point it will need to be replaced or recycled.

      Anyhow, for fun, let’s say we drive the same Skoda Fabia I was renting in Slovakia. According to Google it gets 37.6 mpg highway and 33 city, which seems to be about what I was getting while driving it. Sure it’s underpowered, but it gets up to 4 people where they need to go and is pretty comfortable.

      37 mpg would be .54lbs and 33 is .60

      A ton is 2000 lbs, so at highway speeds it would take 3703 miles, and at city it would be 3333 miles. To get to the emissions that it took to build the electric car our little Skoda would have gone 11851 miles on the highway or 10666 miles in the city.

      After that it’s the difference between .3’ish lbs per mile of emissions.

      However, the total footprint in the other article only goes to between 70-100k miles lifetime for the vehicle. Right now that means our 2010 Toyata Tachoma is end of life, my 911 at 110k should be dead, our 2005 Jetta at 170k should have rolled over, and God bless our old 1998 Jeep Cherokee at 215k before it was rear-ended. A more realistic age of a vehicle should be, in todays day and age, 150k.

      I can’t find numbers yet, but there were some google hits that said electric batteries are good to 100k miles. I’ve heard stories about older cars at some point needing new battery packs, and that those, all in all, are around $5k-8k or around there (more than usual maintenance on regular cars, but still less than what a ICE vehicle would be over the same period).

      So the question would be, and the tipping point is, if the batteries needed to be replaced or if the electric vehicle truly could last as long as an ICE. I’m not going to project the numbers but if someone is replacing an electric vehicle at 100k miles and starting the 8.8 tons of emissions over again, which for the Skoda would be an extra 30-33k miles.

      This isn’t getting into the cost savings and convenience of an electric vehicle for a commuter, which may be where the real value in these are.

      IMO, it’s early, hopefully the numbers aren’t off, someone correct me if I’m wrong.

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