Welcome to SHIFT Basics, a collection of tips, explanations, guides and tips to keep you up to date with mobility technology.
Compared to gasoline cars, electric vehicles are cheaper to run. The main reason is that per unit of energy it costs less to power an electric vehicle than a gasoline car.
In blunt and inelegant terms, electricity is cheaper than gasoline. However, the lowest price depends on your energy supplier, where you live, the energy mix and even what time you bill.
So how are we supposed to figure out how much it costs to charge our electric vehicle?
If you’re trying to figure out how much it costs to refuel your gasoline car, you simply take the tank size in gallons or liters and then multiply that by the cost of the fuel, also in gallons or liters.
The principle of calculating the cost of charging your electric vehicle is roughly the same – except that the units are different.
It’s math time
In this example, we’ll calculate how much it costs to charge your electric vehicle at home. The cost of using public charging stations varies a lot, so it’s best to check with each provider how much it would cost.
Either way, the first step is to figure out how much you are paying per kilowatt hour (kWh).
It’s as simple as taking the number of kWh of energy you used in your last billing period and dividing it by the amount you paid for that bill. This will give you a unit cost per kWh.
Here are some numbers from my friend’s recent energy bill to help us figure it out.
1. According to the bill, my friend used 1,600 kWh of electricity in his last billing period – for my friend they are billed quarterly.
2. It cost them $ 320 (£ 230).
3. Now we want to take this cost and divide it by the kWh used. In this case, it’s $ 320 divided by 1600, which gives us a unit kWh cost of 20 cents (about 14 pence).
Charging cost of an EV
1. Take this unit cost (20 cents) and multiply it by the size of your EV’s battery. This should give us a fairly accurate idea of how much it costs to fully charge your car.
2. Let’s say we charge the Polestar 2, which has a usable battery capacity of 75 kWh.
3. At 20 cents per kWh, fully charging the P2 would cost us $ 15.00 (£ 10.80) – this assumes your system is 100% efficient.
It all sounds pretty simple, right? Well, it kind of is! But there are a few caveats to be aware of.
Depending on your electricity tariff, you may also pay an administration fee or an ongoing fee billed at a fixed rate per day. Do not take these costs into account when calculating your unit cost in kWh, they do not change with electricity consumption.
Your tariff may also charge you a different kWh unit cost depending on the time of day. In some cases it’s cheaper to charge your EV overnight, check your rate to see if that’s the case.
It is also important to know that when charging your electric vehicle, some of the electricity will not get to the battery due to losses in the system. No EV charger is 100% efficient.
If your EV charging system is 90% efficient, you will actually need to purchase more electricity to fully charge your EV. Considering a 10% loss, in our Polestar 2 example, we would need to spend closer to $ 17.00, for a full charge.
Additionally, we also need to remember that EV batteries have a “usable” rating and a “full” size rating. It makes more sense to calculate billing costs using the “usable” rating.
Manufacturers of electric vehicles reserve part of the battery for safety reasons and to support other power demands of the car’s auxiliary components. The “usable” rating is more directly related to the power to which the car’s engines have access. So it makes sense to use this figure.
If all of this is still a bit complicated, many home EV chargers and power providers now provide hardware apps or monitors that tell you how much power you’re using in real time and how much it’s costing you.
These home energy monitors can make your life easier, so check with the EV charging point manufacturer or your home energy supplier to see if those are options.
But if you’re looking for an even easier way to think about it, then researching this article was a number that kept coming up. It costs about half as much to charge an electric vehicle as it does to fill the tank of an equivalent gasoline car.
If you can’t handle (or can’t be bothered with) math, hopefully this is something you can go around the head. Good load, guys.
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Published March 17, 2021 – 13:51 UTC