Welcome to SHIFT Basics, a collection of tips, explanations, guides and tips to keep you up to date with mobility technology.
A few weeks ago, we asked ourselves the question: “How much does it cost to charge an electric vehicle?”
Calculating this – when you are charging at home of course – is a simple case of multiplying the cost per kWh of your electricity by the size of your autoof the battery in kWh.
However, an interested reader asked us another puzzle: how much does it cost to drive a EV per mile. And we’re going to get to the bottom of it.
It’s all about efficiency
When it comes to knowing how much we spend for each kilometer driven, we are simply trying to understand a criterion of efficiency. One that puts our energy consumption in a kind of financial context. But before we can financially compare our efficiency, we need to get a feel for the overall energy efficiency of our EV.
Electric vehicles measure energy efficiency in different ways, and those metrics affect how we calculate how much it costs to drive a kilometer or a mile.
kWh per 100 kilometers
What if your EV measures its efficiency in kilometers (or miles) per kWh? Then you calculate how much each kilometer costs by dividing your electricity costs per kWh by the number of kilometers driven.
It helps to know how much energy you used to travel 100 km, but the numbers are still pretty big. Also, it doesn’t tell us directly how much it costs to travel those 100 km, it just tells us how much energy we have used. Let’s see this.
The first step is to determine how much is 100 km or miles. To do this we need to take the kWh figure and multiply it by how much our electricity costs per kWh.
Let’s say our EV covers 100 kilometers and uses 30 kWh to do this.
If our electricity costs $ 0.14 per kWh, then 30 kWh of electricity costs $ 4.20.
Then getting our cost per mile is simple, just divide $ 4.20 by 100.
In this case, that gives us $ 0.042, or about four cents. Considering that driving a gasoline car can cost anywhere from 10 to 30 cents per km, it is quite economical to drive on electricity.
Kilometers per kWh
If your electric vehicle measures its efficiency in kilometers (or miles) per kWh, the cost calculation for each kilometer is done by dividing your electricity costs per kWh by the number of km driven.
Let’s say our EV is averaging a safe 4 km / kWh.
Knowing that a kWh of electricity costs $ 0.14 and that the energy has helped us travel 4 km, we simply need to divide $ 0.14 by 4.
In this example, it shows that our cost per km was $ 0.035, or about four cents. See how it works?
If you’re concerned about how much you’re spending while driving your electric vehicle, there are two very simple rules of thumb to follow.
If your car measures energy consumption in kWh per 100 km, you want the kWh figure displayed on your car’s dashboard to be as low as possible!
However, if your electric vehicle measures efficiency in kilometers per kWh, you want the kilometer figure to be as large as possible. In this case, kWh is a constant, so you want to maximize the distance traveled with each kWh of power.
All of these calculations are based on the same fundamental metrics: the kWh of your EV’s battery, the kWh used to drive somewhere, distance, and the price of electricity.
By determining their relationship to each other, you will be able to determine how much it costs to drive your electric vehicle a given distance. You will also be able to see at a glance the efficiency of your driving and its financial impact.
As you review these numbers more regularly, you will begin to understand what is inexpensive and effective, and what is not.
It should be noted that these calculations only take into account the costs of the electricity supplying the EV. EVs are always subject to other running costs that add up over their lifetime.
You will still need to replace tires, brake rotors, add windshield washer fluid, and maybe even change bulbs every now and then. Even though these costs may only arise every few years, they are still worth factoring in your car’s overall running costs.
However, during your daily electric workouts, your biggest cost will be the electricity that will power your vehicle. It is therefore advantageous to control your costs per km!
Do EVs Excite Your Electrons? Do e-bikes turn your wheels? Do self-driving cars all charge you?
Then you need the weekly SHIFT newsletter in your life. Click here to register.
Published March 29, 2021 – 12:53 UTC