To calculate how much it costs to charge an electric vehicle (EV) you really only need to know 2 things:
- How big is the battery, aka how much energy it can store. Measured in kiloWatt-hours (kWh)
- The cost you pay your utility for electricity. Measured in Dollars/kWh ($/kWH)
This post isn’t going to go into a lot of detail into the variability in utility rates across the country but your individual utility should have plenty of information to help you find that on their website.
I’ll use my EV (2019 Audi e-tron) and my utility (Georgia Power) as an example. The 2019 e-tron has a battery capacity of 95 kWh. Despite what any information/specs says, I’ve found that we can get about 200 miles when the battery is 100% fully charged (that also makes the number nice and round for this analysis and it’s a conservative estimate).
The image below is from my October 2020 utility bill from GA Power. Utility costs typically are higher in the summer and lower in the winter so this should be a nice average. If I take my total bill amount ($133.54) and divide by total kWh used (1,123) I get a blended (which includes sales tax, nuclear construction cost recovery, etc) cost/kWh of 11.9 cents/kWh.
To calculate how much it costs to charge the car battery from 0 to 95 kWh I simply multiply 95 kWh x 11.9 cents/kWh to get $11.30. I can go 200 miles for $11.30, or a cost of $0.056 per mile.
Let’s look at a similar car from Audi to see how this compares with an internal combustion engine (ICE). The Audi Q7 is a bit bigger than the e-tron but they are close. The 2021 Audi Q7 has a gas tank size of 19.8 gallons and estimated miles-per-gallon (MPG) of 21 combined (city/highway) MPG. If we multiply 21 miles/gallon x 19.8 gallons we get a range of 415.8 miles.
It’s usually recommended to use premium fuel for cars in the luxury segment. Using the Gas Buddy app and finding the gas station near me, the premium gas is $2.19 per gallon. To fill up 19.8 gallons it would cost $43.36, or a cost of $0.104 per mile.
In other words, it costs 1.85 times more to drive the gasoline powered Audi Q7 than the electricity powered Audi e-tron! Along with being lower cost to fuel, since I have a home charging station (it plugs into the NEMA 14-50 receptacle we installed in my garage) I always leave home with a full tank of gas. On the downside, it currently takes a lot longer to fuel up if I have to charge on the road. That will be for another post!