Check My Calculations: Converting to Hybrid or Electric-Only Definitely Decreases Carbon

Assuming CO2 is the pollutant that we're trying to minimize by switching to less fossil fuel-reliant transportation, we can fairly easily calculate whether switching to an electric vehicle will make your carbon footprint better. It's often pointed out to people considering switching to hybrid or electric vehicles that if your electricity is very "dirty" (ie dependent on fossil fuels), you might actually be making it worse. But we have to know the actual amounts of carbon produced by each.


CALCULATION

ELECTRIC
A 2017 Tesla Model S 100D goes 335 miles on 100 kilowatt-hours (= 0.1 Megawatt-hours.)

According to EPA's power profiler tool, generation of my power (CAMX zone in California) produces 527.9 pounds of CO2 per Megawatt-hour, just over half the national average. (The number for Pennsylvania is 758.2.)

So to go 335 miles, you use 0.1 Megawatt-hour x 527.9 pounds CO2/Megawatt-hour, which is 52.8 pounds.

GAS
Burning a gallon of gasoline produces 20 pounds of CO2.

Assuming a gas car would get 25 mpg, going 335 miles would use 13.4 gallons.

13.4 gallons x 20 pounds CO2/gallon = 268 pounds of CO2 = five times more than the Tesla.


Charging your car in Pennsylvania is 1.4x worse in terms of CO2 but that barely makes a dent and electric is still much better than gas. In fact electric is still better even if your power is only as clean as the national average, and your car is getting 50 mpg, you still do more harm with a gas car. Or even if you get an electric or hybrid with mileage not as good as Tesla; every single one of these values has to change a lot before it makes a difference to the final answer.

The same argument applies to hybrids. As long as electricity is any better than gasoline, the more gas you convert to electricity, the better. If these calculations are incorrect please point out what I'm doing wrong.

The bottom line is that the next time you hear "well your electricity is polluting too so getting a hybrid or electric doesn't help", tell them about this.

(You may not want to hear it, but converting more energy to not just solar and wind, but to nuclear, is the best bet.)