• Kecessa
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    9 months ago

    https://www.autoexpress.co.uk/sustainability/358628/car-pollution-production-disposal-what-impact-do-our-cars-have-planet

    5.6 tons of CO2 to produce a gas car, 8.8 tons of CO2 to produce an electric car.

    We’ll use 10k km/year as a baseline (with is way less than average)

    Three Toyota Corolla, 2010, 2015, 2020

    They release 1.8, 1.7, 1.6 tons of CO2 a year respectively driving 10k km (fueleconomy.gov)

    The EV is a 2024 Toyota bZ4X (what a stupid name) and it releases zero CO2 a year to drive 10k km

    So we’re in 2024, the emissions from the gas cars so far are:

    2010 > 5.6 + (1.8 x 14) = 30.8 tons

    2015 > 5.6 + (1.7 x 9) = 20.9 tons

    2020 > 5.6 + (1.6 x 4) = 12 tons

    Total: 63.7 tons

    So we can already see that the 2020 has released enough CO2 in 4 years to beat an EV.

    Let’s say we add another 5 years to each cars… We’re now at 39.8, 29.4, 20 tons respectively for a total of 89.2 tons

    Now, what’s the impact in 5 years if we take the 2010 off the road and introduce a 2024 EV instead? Scraping the 2010 releases CO2, it’s evaluated at half the production so 2.8 tons. So our new numbers are:

    33.6, 29.4, 20 and 8.8 for the EV for a total of 91.8

    After five years with the 2010 off the road we’re at 91.8 - 89.2 = 2.6 tons extra so two years from being carbon negative compared to never changing the 2010 for an EV.

    Two more years of gas car: 89.2 + (2 x 1.8) + (2 x 1.7) + (2 x 1.6) = 99.4 tons

    What’s the portrait in two more years if we had scraped the 2010 in 2029 instead?

    89.2 + (2x1.7) + (2x1.6) + 8.8 = 104.6 tons

    By switching in 2024?

    91.8 + (2x1.7) + (2x1.6) = 98.4 tons

    By scraping the 2010 in 2024 we saved 6.2 tons of CO2 in 2031(equivalent to 3.4 years of driving the 2010) compared to doing it in 2029.

    If we didn’t scrap it at all and didn’t introduce an EV to replace it, we would be at + 1 ton in 2031 and it would keep increasing the longer we keep the 2010 on the road.


    Keep in mind that that’s with less than half the annual average mileage in the USA (14k miles/22.4k km) AND it doesn’t take maintenance into consideration and gas cars need more of it and it pollutes more (lots of oil) so the real difference is even greater!


    • Ookami38
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      9 months ago

      Cool, some numbers. First off, looking over your math, it looks correct, so that’s good. The article seems to be a bit confusing, however, or you’re taking a best case scenario they don’t approach in the article. It states that an EV takes 8.8 tons of co2 to produce. It later states, however, “However, a BEV (battery electric vehicle) produces less harmful emissions over its entire life. The study found that a medium-sized petrol or diesel car produces around 24 tonnes of CO2 versus a BEV’s 18 tonnes” this seems to imply to me that we shouldn’t keep emissions at 0 throughout the EV’s lifetime? I would assume this additional tonnage is from less-clean electrical generation methods and overall maintenance requirements.

      If this is the case, it paints a bit different of a picture, more in line with what I said - that you should buy one if you’re going to buy a car anyway, and drive yours. What the numbers provided does give us now, though, is a point at which the sunk cost DOES become too large, and that seems to be a car in the age range of 10-15 years at present.

      Please, if I’ve misunderstood something with the article, correct me, and thank you for the write up with sources.

      • Kecessa
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        9 months ago

        I added a “disclaimer” after the fact to mention that it’s based on mileage way under what people actually drive and it doesn’t take maintenance into consideration, with “real” mileage we’re better off switching to an EV now because the switch makes you carbon negative after 5 years or so. The numbers used are appropriate in the sense that in both cases we don’t count the CO2 coming from the production of the energy source used by either of them. If the vehicle life is the same, the 24 and 18 tons numbers (which seem to be under what would be expected based on the math I’ve done, that’s a 10 years life expectancy for the gas car???) also show that the quicker we get rid of the gas cars, the quicker we reach a point where we’re carbon negative compared to continuing to drive the gas cars until they’re not drivable anymore.

        If we go with a number much closer to the actual average (20k km/year) you can buy a new Corolla, replace it the next year with an EV, park the Corolla and never drive it again and the math goes like this:

        5.6 (prod )+ 2.8 (scrap) + 3.2 (driving) + 8.8 (EV) = 20.4 tons

        Years to reach 20.4 tons if we drive just the Corolla > 5.6 + (3.2 * X) >= 20.4? X = 5 years of ownership = 21.6 tons

        After 4 years of owning the EV you’re carbon negative in comparison.