We recently rented a Tesla Model Y from Hertz and took it on a 900-mile round trip through the Adirondacks, Quebec, Vermont, and the Hudson Valley. This was a bit of a test-drive to see if an electric vehicle could put up with being driven on a road trip that we had planned without much thought to where we’d fill up. It was a fairly smooth trip fuel-wise went despite spending a good chunk of the trip camping with no electrical hookup.
However, this article isn’t about our road trip, it’s all about how charging an EV works and how much it costs. Does electricity beat gasoline as a fuel? It depends. Read on for more.
How to refuel
Tesla has its own proprietary network of Superchargers, which will fill your car from mostly empty to mostly full in 30 minutes. In 45 to 60 minutes it fills the battery to full, which registers as roughly 329 miles til empty. Connecting to a Supercharger immediately starts the charging and payment, which is charged back to you through Hertz. The rate you are charged at is not directly stated, but is roughly $0.48 per kWh (more on that later).
We used these to fill the car up to full while on the road and added hundreds of miles at a time. In Plattsburgh, we charged from 20 miles up to 320+ miles in an hour.
Other networks exist, such as ChargePoint, which we used several times in Vermont and New York. These chargers add the equivalent of roughly 22 miles per hour, though the charging may be halved when two vehicles are connected to the same charger. Interestingly, charging is halved even when the other connected vehicle is no longer charging. Prices are set by the owner of the charging point, which ranged from free, to $0.16 per kWh, up to $1.75 per hour.
In practice, these were only good for 20-40 miles of charge at a time because we only used them while parked and visiting a town for 2 hours at a time. At this charging rate, you would need 10-12 hours to fill the battery.
How to understand fuel economy
It’s a bit of a mathematical mess to conceptualize how much it costs to fill up an EV. Some places charge you by the minute, others charge you by the kWh, others, Tesla for one, highlight only the price and how much mileage you’ve charged up.
The equivalent to miles per gallon for EVs is kilowatt hours per mile, which is a number determined by the type of vehicle, how fast you drive, and the route you take. Once you understand the price per kWh, you can calculate cents per mile driven, which is how to compare cars with different fuel types.
The issue is that car mileage isn’t measured in cents per mile. To understand the equivalent fuel price you need to take miles per gallon of a typical car and the price of gas and divide one by the other.
In the example below, I’ve used the fuel efficiency numbers from here, prices from ChargePoint and Tesla from our recent trip, and an average recent gas price and economy car mileage.
Tesla Model Y
ChargePoint: $0.16 per kWh X 0.28 kWh/mi = $0.05 per mile. This price is essentially the same price as charging at home.
Tesla Supercharger: $0.48 per kWh X 0.28 kWh/mi = $0.13 per mile
Economy gas-powered vehicle: $4 per gallon / 35 mi/gal = $0.11 per mile
“Gas guzzler”: $4 per gallon / 20 mi/gal = $0.20 per mile
As measured in cents per mile, filling up at ChargePoint is less than half the price when gas is at $4, while a Tesla Supercharger is slightly more expensive per mile. If you compare against a “gas guzzler” that gets 20 mpg, the numbers look even better.
The bottom line is that charging at home, assuming the home electric price is similar to ChargePoint, will cost less than half the fuel cost of an economy gas-powered vehicle when gas is at $4/gal. Somewhere like Quebec, where the kWh price is around $0.07, the math is even more favorable to EVs.
When on the road, the Tesla Supercharger network allows you to fill up at a price equivalent to roughly $4/gal gas.