Why BEVs are not meaningfully more efficient than other kinds of green cars (even if you assume everything they say about BEVs is true!)
Part II: The amount of emissions generated by battery production
Now at this point, some BEV fan might come in and say: "It's still the most efficient car! Might as well get the most efficient one regardless!" This however ignores one major problem: The amount of emissions generated by battery production. Now, you might have heard this argument before, and it's usually dismissed by someone claiming that "it is a tiny thing, and it pays itself back after just a few years of driving!" But this claim misses a major point. This is only true when compared to conventional cars that are highly inefficient. When compared to other green cars, that payback period is much longer. If you understood the first half of this post, then you'll will realize this is not going to happen so fast. I will compare the BEV to the FCEV and hybrid.
First, we need to figured out how much upfront emissions a BEV produces as part of its battery production. To do that, I will take the difference in battery capacity and multiple by CO₂ per kWh of capacity. I will use the Model 3 as a stand-in since many EVs have about the same battery capacity. The Model 3 LR has a battery capacity of 78.1 kWh [1] and I will assume that both the hybrid and FCEV will have 1.5 kWh (which is close to the real numbers). Or a difference of 76.6 kWh. Li-ion batteries apparently have a emissions of 150 - 200 kg-CO₂ per kWh of capacity [2].
To ensure that I stay impartial, I will use just the low end of this figure, 150 kg-CO₂ per kWh, because someone will simply accuse the higher numbers of being too high. Also, it works as a way to hedge against the argument that I am missing the emission numbers for the production of components found exclusively in the hybrid or FCEV. If someone brings that part up, I can point out that I am using the low end of the range for battery production and that it is being generous to the BEV. Ultimately, this gives us 11,490 kg-CO₂ more upfront emissions when compared to the other two cars.
Next is to figure out how much CO₂ these vehicles emit per mile of driving. To do that, we must find out how dirty each source of energy is, and divide that by the MPG/MPGe figures of each type of car. I will use these numbers [3] [4]. Again, I will not challenge them and I will accept them as is nor will I will try to use any fudge factors. The goal is to be impartial again. Electricity is grid electricity, gasoline is conventional gasoline, and hydrogen is gray hydrogen. Like in part I, I will convert to GGE (33.7 kWh/gallon) where convenient. Also, the figure for gray hydrogen is converted from 9.3 kg-CO₂/kg-H₂.
Electricity production in the US averages 0.371 kg-CO₂/kWh, or 12.5 kg-CO₂/GGE
Gray hydrogen is 9.4 kg-CO₂/GGE
Gasoline is 8.78 kg-CO₂/gallon
When combined with the MPG/MPGe figures of each car, you will get this:
Type of car
MPG/MPGe
CO₂ per gallon/GGE
CO₂ emitted per mile
BEV
141
12.5 kg
88.7 grams
FCEV
74
9.4 kg
127 grams
Hybrid
56
8.78 kg
157 grams
Now that we have the CO₂ emitted per mile, now we can figure how long it takes for a BEV to make up the upfront emissions of the battery via driving. The result is the following: Compared to the hybrid, it will take (11,490 kg) / ((157 - 88.7) grams) = 168,228 miles of driving! Compared to the FCEV, it will take (11,490 kg) / ((127 - 88.7) grams) = 300,000 miles of driving!
Those are ridiculous figures! You will need to drive an insane amount of miles to make up for the battery in the BEV! This is especially notable when comparing the BEV to the FCEV. Your BEV battery might not last long enough to see 300,000 miles, and therefore it might never happen. And in any case that is going to be more than 20 years of driving for most people. Even if you can get 100% green electricity, this still takes the following amount of miles: (11,490 kg) / ((157 - 0) grams) = 73,185 miles versus the hybrid, and (11,490 kg) / ((127 - 0) grams) = 90,472 miles versus the FCEV.
Those are still big miles, and suggest that break-even is still a long ways off even in the ideal situation. And of course, if you can assume 100% green electricity, it becomes fair to assume green fuels (such as eFuels) or green hydrogen as a point of comparison. In that scenario, break-end never happens.
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