Estimates of charging costs for electric vehicles compared to fuel costs for petrol cars are misleading

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I just saw a headline on Google yesterday: “Is charging an electric vehicle cheaper than petrol? Here’s what the numbers and experts say.” Immediately I thought, “Ugh…” I’ve been doing running cost analysis and comparisons between petrol and electric cars for years, and anyone who has done it even once knows that there are many different factors that vary from person to person. Now, the positive side of this is that this article wasn’t about total cost of ownership, so we don’t have to consider resale value/depreciation, maintenance, insurance costs, etc. This makes it a lot easier. But it’s still not a simple mathematical equation that’s the same everywhere and for everyone.

There are a few key factors that affect fuel and charging costs: 1) the average price of gasoline for the period under consideration, 2) the average price of electricity for the period under consideration, 3) the efficiency of the vehicles you are comparing.

Taking the national average for the first two and then selecting two similarly shaped vehicles for the third is not going to be helpful or relevant for most of us. This means that giving someone a simple mathematical answer without explaining the nuances will be misleading, possibly high misleading.

For point 1, also consider that you need to determine the average price you would pay over the course of the comparison period. 3 years? 5 years? Nobody knows the answer because we don’t know how gasoline prices, which can be very volatile, will change over that time. For point 2, it’s not just how electricity prices at home will change over the same period, but also how much you charge at home versus free charging stations at work or in stores versus much more expensive high-power fast charging stations. I used free chargers for years, so my charging costs were close to $0 for a long time. Some people drive long distances regularly and use fast chargers frequently. Also, within the comparison period, you have to consider whether those habits and norms will change.

In terms of the models you’re comparing, you might actually be comparing two similarly efficient models, or you might be comparing a large, inefficient truck and a much more efficient crossover. This is obviously very important. What are your priorities and which models appeal to you most?

All in all, as you can see, it is not possible to say across the board that an electric vehicle will be much cheaper or more expensive than an alternative petrol vehicle. However, electric powertrains are about 3-4x more efficient than combustion engines, and charging with household electricity is much cheaper than generating the same propulsion power with petrol. But yes, generalisations are generalisations – they may or may not apply to you.

Anyway, to return to the article I referenced above, it is hard not to be fascinated by the calculations or the statements of the experts. Here is the key message:

Using U.S. averages, we found that the monthly cost of charging an electric vehicle is $66.66, while the cost of fueling an internal combustion engine vehicle is $182.50.

Using the figures above, you can do an annual cost comparison here:

• • $2,190 Average annual fuel costs for a car with an internal combustion engine
  • $799.92 Average annual cost of charging an electric vehicle
  • That is an annual difference of 1,390.08 USD

You also pointed out the different nuances and aspects to consider. So the article itself was good. But I’ll say it again: you have to bring in your own assumptions to really be able to make a relevant comparison for yourself. The good news is that based on the averages, many of us can expect to save a lot of money by driving a car that runs on electricity rather than gasoline. That was certainly the case for me!