How much does EV add to your electricity bill?

One of the most common questions you’ll typically hear EV (electric vehicle) owners or those looking to buy one ask is: “How much does to cost to run an EV?” or “How much does an EV add to my electricity bill?”

Sit back and enjoy the read as we discuss the impact on your electricity bill when you charge your EV at home.

How EV charging at home impacts your electricity bill

Before we even begin to scratch the surface in order to discover the true cost of charging an electric vehicle at home, we must consider the pence per kilowatt hour (kWh) factor, as opposed to pence per litre, which would have been the case if our car were running on petrol. 

Now, ‘kWh’ is the standard energy measurement unit that energy suppliers in the UK use to bill homeowners and refers to one person consuming 1,000 watts of power for an hour. When it comes to home charging, your electric bill will indicate this cost and, on average, it can be anywhere between 10 and 14p. So, for comparison’s sake, if petrol is 128p for every litre, then electricity is between 10 and 14p per every kWh. 

We have so far understood the cost of electricity but another very crucial factor we need to take into account is the size of your electric car’s tank. Let’s say your EV has a 40l tank and the cost of petrol is £1.28 per litre, then the cost to fill it up would be £51.20. With an EV, however, your tank now represents how many kWh of energy it can hold at any time. So, the larger the capacity to store this energy, the larger the tank. At the moment, the Tesla Model S 100d has the largest battery size, which essentially means it can store 100 kWh of energy – that’s what the “100d” actually represents in the model number. 

The next thing to consider is the cost to charge your EV – for this, we’re going to assume that the price per kWh is 10p. Therefore, for a Model S 100d, it would add £10 to your electricity bill (10p x 100); for the Nissan Leaf, it would add £3 since the battery size is “30”; or, say, the BMW i8 which has a battery size of “7”, it would add just £0.70 to your electricity bill. 

Here’s a very simple formula you can use to determine the cost of charging your EV from a completely empty battery to full: Size of the battery (kWh) x Energy cost of your supplier (pence per kWh). 

So, if your Tesla Model S’s Supercharger network costs £0.28 for every kilowatt-hour, you’d be looking at an addition of £28 to your electricity bill (100 x 28p). This is, again, if you’re charging from fully empty-full.