Cost of EV Charging vs. Gas Fueling and how to calculate
The cost of charging vs. fueling is a question many people interested in EVs ask.
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There are a multitude of reasons you may be thinking about making an electric vehicle your next car purchase. Maybe you’re excited about the “cool factor” of EVs, looking to reduce your environmental footprint, or simply looking to save money on driving.
Certainly one of the biggest questions from people who are thinking about purchasing an electric vehicle is how the fueling costs will compare to their current gas car.
In this guide, we’ll provide a high-level overview comparing the cost of charging an electric vehicle versus a gas car using some example numbers. Then, to close, we’ll provide you with step-by-step instructions on how to calculate the relative cost difference between EV and gas, for your specific situation.
Is charging an EV cheaper than filling the gas tank?
Generally, driving an electric vehicle around will be a bit cheaper than a gasoline car, but a lot of it depends on whether you’ll be using an at-home charger or utilizing public EV chargers.
Charging at home can be a huge money saver, drawing energy at your local power utility’s rate per kilowatt-hour (kWh). Residential electric rates vary by region, usually from $0.10 to $0.25 per kWh – but let’s just average to about $0.15 per kWh for discussion purposes.
Costs to charge at a public charger vary quite a bit by region and charger pricing models, but are typically about 2 to 4 times more expensive than charging at home.
Middle-speed Level 2 AC Chargers are usually around $0.20 to $0.30 per kWh.
High-speed Level 3 DC Fast Chargers (the ones that can charge your car in less than an hour) usually cost around $0.40 to $0.60 per kWh.
Make a mental note of these numbers and their relative costs, as we’ll revisit them later:
At-home charging: $
Level 2 Public Charger: $$
Level 3 Public Charger: $$$$
Comparing gas mileage to electric vehicle efficiency
The first step to figuring out the cost comparison between a gas vehicle and an electric vehicle is understanding the energy efficiency units of both vehicle types.
For gasoline cars we’re all familiar with their measurement of efficiency – miles per gallon, or MPG – that is, the distance you can go per gallon of gas burned.
As for electric vehicles, you may have seen window stickers at the dealership or car websites express EV “mileage” in terms of MPGe, or miles per gallon equivalent. Many EVs on the market today clock in around 100+ MPGe, meaning that they are about three to four times more energy efficient than an average gasoline car that gets around 30 to 35 mpg.
However, the MPG vs. MPGe comparison only measures the relative energy efficiency, not necessarily the cost efficiency of driving an EV versus a gas-powered car.
Cost per unit of energy of gas vs. electric vehicles
Directly comparing the cost of gas ($/gallon) versus the cost of ($/kWh) for an EV is apples versus oranges. We first need to convert them into the same units to properly compare them.
The easiest and purest way to compare EV vs. gas costs is converting the price of gas per gallon into the price of gas per kilowatt-hour (kWh).
The EPA has calculated the energy content of a gallon of gas to be about 33.7 kilowatt-hours (kWh). Therefore, to calculate the cost per kilowatt-hour of a gallon of gas, divide the cost per gallon by a factor of 33.7.
So in a scenario where gas costs $4.00/gallon, the cost per kilowatt-hour of gas would about $0.12/kWh. You might recognize that this unit cost is about the same or cheaper than the typical at-home residential electric rate. If that’s the case, how could driving an EV possibly be cheaper than driving a gas car?
Remember from above that electric vehicles are about 3 to 4 times more energy efficient than a gas-powered car with an internal combustion engine. Therefore, to drive the same distance as an electric vehicle, your gas car would have an equivalent energy unit cost of about $0.35 to $0.50/kWh.
Based on the charging costs mentioned earlier in this article, the cost of driving an EV compared to a gas-powered car can be substantially cheaper, but it depends on where you charge:
If charging at home on a Level 1 or Level 2 charger at an electricity rate of $0.15/kWh, “fueling” an EV would be about one-third the cost of a gas car.
If using a public Level 2 AC charger at $0.20 to $0.30/kWh, an EV would be about half the cost as driving a gas car.
However, if using a public Level 3 DC Fast Charger at $0.40 to $0.60 per kWh, it would be about the same cost as fueling a gasoline-powered car.
Cost per distance of gas vs. electric vehicles
A more tangible way to relate to this would be thinking about how much a tank of gas costs versus a full battery charge.
A typical EV has a battery capacity of around 70 kWh. So to charge an EV from 0% to 100% based on the $/kWh rates we’ve been using, it would cost:
$10.50 for at-home Level 1 or Level 2 charging
$14.00 to $21.00 to charge on a public Level 2 AC charger
$28.00 to $42.00 to charge on a public Level 3 DC Fast charger
That 70 kWh battery can typically provide an EV range of about 270 miles today. Comparing to a gas car that averages 32 MPG, that gas car would use about 8.5 gallons of gas. At $4.00/gallon, going those same 270 miles would cost about $34.00 of gas
So as you can see, charging an EV at home would likely be about 1/3 the cost of buying gas, using a public Level 2 charger would be about half the cost of buying gas, and using a Level 3 DC Fast charger might be about the same price or slightly more expensive.
How to calculate the relative cost of charging an EV vs. fueling your gas car
Now that we’ve walked you through the examples, here’s a step-by-step guide on how to calculate the relative cost based on your specific desired EV, gas car, and energy costs.
Step 1: Convert the cost of gas from $/gallon to $/kWh
Take your local cost per gallon of gas and divide it by 33.7, which is the kWh energy content in a gallon of gas.
For example, $4.00/gallon divided by 33.7 kWh/gallon = $0.118/kWh
Set this number aside, as it will be used in Step 3
Step 2: Calculate the energy efficiency factor of an EV vs. your gas car
Take the MPGe of the EV you are looking at
Divide it by your gas-powered car’s MPG
For example, 110 MPGe divided by 30 MPG = an energy efficiency factor of 3.6
Set this number aside, as it will be used in the next step
Step 3: Calculate the true energy cost to drive your gas car compared to an EV
Multiply the results from Steps 1 and 2
For example, $0.118/kWh times 3.6 = $0.425/kWh
To better explain this step, because a gas car is less efficient than an EV, for every 1.0 kWh of energy that your EV consumes to go a certain distance, your gas car would consume more energy (3.6 kWh in this example) to go that same distance. By multiplying the unit cost of gas per kWh by the energy efficiency factor, we’re normalizing the cost of driving a gas car to that of an EV, enabling us to make an apples-to-apples comparison between gas and EV costs to get from the same Point A to the same Point B.
Step 4: Compare the costs
Make a chart comparing the following prices:
Gas-Powered Car – Plug in the result from Step 3
At-Home Charging – Plug in the cost of your residential electricity per kWh
Level 2 Public Charging – Plug in the $/kWh from your local Level 2 Charger
Level 3 DC Fast Public Charging – Plug in the $/kWh from your local Fast Charger
Bottom Line
Charging an electric vehicle can be significantly cheaper than buying gas for your car to travel the same distance. Based on current energy costs and electric vehicle efficiencies versus gas-powered vehicle efficiencies, charging an EV is about 3 times cheaper than filling up the gas tank on a comparably-sized car. The energy cost of an average gasoline-powered car the same distance as an EV can cost in excess of $0.40/kWh, whereas an EV can be charged for about $0.15/kWh or less, depending on energy costs in your region.
The savings are a result of EVs being 3 to 4 times more energy efficient than a car with internal combustion engine.
It is important to note that these larger scale cost savings are mostly only achievable if you charge your EV at home and pay residential rates for electricity.
If you live in an apartment building or otherwise don’t have access to a plug at your home, you may be forced to use a public Level 2 charger. Rates for Level 2 chargers are usually in the $0.20 to $0.30/kWh range. It’s definitely not as cheap as at-home EV charging, but still about half the cost of fueling a gasoline-powered car.
For road trips, or any situation where you need to rapidly charge, using public Level 3 DC Fast Chargers will be roughly equal to the cost of filling a gas tank. Charging will range between $0.40/kWh to $0.60/kWh, which is about the same cost as operating a gas car.