Does EV charging cost more than running a petrol car?

The recent cost of living price rises have included significant electricity price rises. As a result, I’ve recently been asked ‘does this mean EVs are getting close to petrol car running costs?’

Well, back in late 2022 I did a comparison of the ‘refuelling’ costs of a battery electric vehicle (BEV) over a petrol driven car and found then no matter how you charged your BEV, the ‘refuelling’ costs were always significantly cheaper than for a petrol cara.

Given the cost of living issues, I thought this would make a good excuse to recheck the figures in case things had changed. After all, price rises have hit all of petrol, electricity and DC fast-charging … plus Tesla has entered the DC fast-charger market by allowing non-Teslas to charge at many of their Supercharger sites. (Albeit at a premium price of 82c/kWh).

In that earlier article I noted that studies show home charging makes up somewhere between 70% and 95% of all recharging events. (The rest being made up of mainly AC destination charging plus a lesser percentage of DC fast-charging). From that, I came up with an approximate (if slightly arbitrary) choice to use 90% AC charging and 10% DC in the analysis, which I am sticking to for this article.

On the other hand, for this article I have worked to better define some of the other parameters and data. These include:

1. Using the average of all the Victorian government mandated default offer prices for peak and off-peak electricity (by the way, these are perhaps some of the more expensive in the country).
2. Adding a comparison cheaper kWh tariff. This is the WA super off-peak tariff of 8.2c, which is available from 9am to 3pm daily.
3. Improving the average kWh/100km figure for BEVs by creating a (non-weighted) average of the WLTP ratings for the top ten selling BEVs in Australia for 2023. This is my simplified version attempting to match the Australian new car fleet L/100km average for all new car sales. Given the ABS gave up calculating that number in 2021: for the moment this is the best I can come up with for a BEV equivalent!

Putting this all together, my revised and updated review of the costs of running an EV on different chargers and tariffs are shown in table 1. (By the way, these are not directly comparable to the table in the 2022 article as I have more formally defined the peak and off-peak electricity tariff kWh price and changed the way I calculate the average kWh/100km number).

Table 1: costs for running a BEV using different charging sources and electricity tariffs

Reviewing the data: the point I made back in late 2022 – and which is further brought home by the addition this time of the West Australian super off-peak tariff – is that EV running costs are principally controlled by the kWh electricity price you pay at home. Back in 2019 I wrote that home charging would add around 30% to the usage component of an electricity bill. Since then, electricity rates (and petrol prices) have gone up – but that relativity still holds true.

Looking at Table 1, we can see there that running a BEV still costs considerably less than running a petrol car. This applies even if you chose to use the most expensive DC charging system for 100% of your charging needs. Table 2 summarises this:

Table 2: summary of cost and percentage savings of BEV over petrol vehicles.

By the way – just as I was finishing off this article, I realised I haven’t included running an EV off your own solar. (Something I can perhaps detail in a future update ☺ ). In brief: an approximate kWh cost for self-consumed solar is around 6c/kWh. This would provide savings even greater that the WA super-off peak rate comparison shown in table 1.

Also – both a better defined weighted average kWh/100km figure for BEVs sold and finding average Australia prices for peak/off peak kWh costs would likely change the savings further in favour of a BEV.

(Given Victoria’s tariffs are relatively high in comparison to other states and the most numerous BEVs by far sold here are the highly efficient Tesla Model 3 and Y pair, plus the rest of the top 10 are mostly quite efficient too. For instance, my first efforts to create a weighted average resulted in a value of 13.8kWh/100km – but it needs far more work and checking before I am prepared to use it).

Summing up:

Yes, like petrol, electricity costs have increased. However, if cost-of-living increases are worrying you: this analysis shows that rather than reconsidering buying a BEV, it could be well worth reviewing your electricity retailer and tariffs as there could be plenty of savings to be had there. (That is assuming you live in a state/territory with more than one electricity retailer).

However, if you are currently running a BEV on any form of charging system and pricing, rest assured you are still making significant savings over running a similar sized fossil fuelled car.

On the other hand, if you are thinking of swapping to a BEV: rather than avoiding buying one, the recent cost of living rises are just one more reason to make that switch to lock in the fuel, service and climate damaging emissions savings that a BEV offers.

Footnote:

1. As petrol cars make up over 70% of the national fleet (ABS data), I didn’t include diesel cars in the initial analysis. Given the size of the savings, I decided there was no point in adding the additional column and data as it did not materially affect the conclusions.