Can a Prius Prime beat an EV in lifecycle carbon emissions?

Discussion in 'Prime Main Forum (2017-Current)' started by Don Hess, Nov 14, 2021.

  1. Don Hess

    Don Hess New Member

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    In reviewing the carboncounter website, the PP is listed as the most efficient (carbon emissions) PHEV of all at 133MPGe/54mpg. The Tesla Model 3 (base model) is listed, as a comparison, at 140 MPGe. When drilling down on this comparison on the website, it shows that lifetime carbon emissions for the PP are higher than for the Model 3. But, initial vehicle construction emissions for the Model 3 are significantly higher for the Model 3 than for the PP, substantially due to the much larger battery found in the Model 3 compared with the relatively small (8.8kWh) battery found in the PP. The use and burning of gasoline over time however eventually pushes the lifecycle carbon emissions of the PP above those of the Model 3.

    Now, I am currently getting an average of 170mpg on my PP, way above the EPA listed mileage of 54 mpg. My goal is to get to 200mpg. Obviously, the only way this can be done is by maximizing driving in EV mode. I am curious at what point (mileage-wise) does the PP become more efficient (less carbon emissions) than the Model 3? I haven’t found any way to determine this yet.
     
  2. dbstoo

    dbstoo Active Member

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    The fun in this question is that there are many scenarios that trip the balance in different directions. Are you driving them both exactly the same? Are you taking into account the impact of detours to a charging station? Is the comparison capturing the energy used when warming the Telsa battery prior to a high speed charge?

    Long distance commutes and frequent long trips (500 miles or so) are not the average for Tesla drivers. The average driver travels less than 25 miles a day.

    If you are an average USA driver who drives less than 25 miles a day, then the gasoline virtually never comes into play if you simply charge overnight. In those cases, the Tesla is vastly overbuilt with way more range than is normally needed and the Prius will be the winner.

    But if you take it the other way, and drive both cars a long distance daily and drive them until they no longer run, the Tesla should eventually come out ahead.
     
  3. AldoON

    AldoON Member

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    Comparing 133 MPGe on the Prime vs 140 MPGe on the Model 3 means that the Model 3 is slightly more efficient when driven in EV mode only.

    This means that even under best case scenario (100% EV driving or infinite MPG) the Prime will still eventually have a higher carbon footprint. The question is how long will that take? My guess for this scenario is a lot longer than the useful life of the car.

    To get a more realistic estimate you could make an assumption for how many miles you expect the car to last. With that you can figure out the carbon footprint of the Model 3.

    The question then becomes how much EV mode driving do you need to do on the Prime to match that. You'd need include the carbon footprint of driving x miles in EV mode at 133MPGe + y miles in HV mode at 54 MPG. Depending on your assumed useful life, it could work out that even with zero HV driving the Prime never beats the Model 3.

    Note that the MPG number shown on the Prime is not useful because it doesn't include energy put into the car from charging. If you drive 1,000 miles with 5 gallons of gasoline it will say 200 MPG regardless on how much electricity you added through charging.
     
  4. Salamander_King

    Salamander_King Senior Member

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    As you know very well, your 170mpg can not be compared to EPA-rated 54mpg. The number must include the EV mode driven miles. The EPA number is purely for HV mode gas milage. That being said, it is not very hard to beat that EPA-rated HV mode only mpg.

    As for your question, there are so many variables involved, it would be impossible to pinpoint mpg displayed on the dash to be compared to M3 carbon emission. I am sure that the carbon counter website you looked at must have made some assumptions to make the comparison possible. That assumption, such as how many miles/year, how many miles/trip, how often you charge, how fast you drive, etc, etc. No one drives exactly as assumed in this comparison model. But all things considered, it would be a fair estimate that if you do drive predominantly in EV mode, that is you are mostly driving less than 25 miles/trip for the life of the ownership, it is likely that PP has less lifetime carbon emission than Model 3 driven as similar ways.

    If you really want to come up with some number, you can dig further into the smallest prints on the carbon counter website to find out the amount of CO2 emission for the production phase of PP vs M3. If you can find that number, then it would be possible to calculate the max amount of gasoline you can burn during the ownership of PP and still comes ahead of M3 for the total CO2 emission at the end, assuming all other variables to be equal and PP's EV efficiency to be 133mpge and M3 to be 140mpge.
     
    #4 Salamander_King, Nov 16, 2021
    Last edited: Nov 16, 2021
  5. Trollbait

    Trollbait It's a D&D thing

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    Yes, if the amount of carbon emitted from gasoline usage is less than the difference in manufacturing emissions.
     
  6. MTN

    MTN Active Member

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    Driving more miles to save carbon emissions? Walk or ride a bike and you'll beat the Model 3 by far.
    Don't have a kid(s) and you'll beat the Joneses by even further.

    *the soap box I'm on is recycled and about to fail ;)
     
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  7. don_chuwish

    don_chuwish Well Seasoned Member

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    This doesn't give you the answer but might help you contemplate it:

     
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