EVs cheaper than petrol? Depends where you charge them
An EV could still be cheaper to run after road user charges are introduced on April 1, a new study says.
But it will depend on where you charge.
The Electric Homes report, produced by the non-profit Rewiring Aotearoa and peerreviewed by Professor Shaun Hendy, says it costs $102,935 to run an average-priced petrol car over 15 years — including the upfront price of the vehicle, servicing and fuel bills.
It says an EV costs more upfront, and will incur RUCs, but lower servicing and energy bill costs will see a cheaper total cost of ownership over the period at $91,751.
But that’s only if you charge your EV at home.
If you top-up at more expensive public fast chargers, where the going rate is 80 cents per kilowatt hour, the total cost of ownership for an EV is more expensive than a petrol car at $116,310. The cheapest 15-year option is an EV charged by home solar panels, which is put at $83,838 (a home solar installation can easily cost north of $20,000; one Tesla Powerwall battery will cost you $11,800 alone, two is $23,600, three $35,400 plus a $1900 Gateway to connect them to your home and your solar panels — which will cost thousands more. Rewiring Aotearoa says that if your bank offers a low-interest “green loan”, solar power can cost 17-28 cents per kilowatt hour compared to the average home paying 33c per kWh.
The report says a petrol car has the highest annual running cost ($4336) followed by an EV topped up at public fast chargers ($3867), an EV changed from the grid at home ($2230) and an EV charged by solar at home ($1703).
It says: “The cost of filling a 50 litre tank of a petrol vehicle is about $130 (at $2.60 per litre), which includes fuel excise similar to RUCs. Filling the ‘tank’ of an electric vehicle to go the same distance is about $30 from the grid, and about $10 from solar, before RUC costs.”
Its EV costs included $2000 for a home charger mains power trickles chargers at 1.4kW — meaning it can take up to 50 hours to fully charge an EV.
A 7.4kW home charger can supply about 40km of range per hour. A 25kW public fast charger can deliver about 33km of range in 15 minutes, a 50kW fast charger 66km in the same quarter hour.
The report quotes European research that sees EVs reaching price-parity with petrol cars by 2026. A Garner study released earlier this month predicts electric cars will be cheaper to make than an Ice (internal combustion engine) equivalent by 2027, largely thanks to big car makers moving to cheaper “gigagasting” manufacturing — though with the flipside that it will make EVs more difficult to repair, and insurance more costly.
For road user charges, 11,000km mileage a year was used, close to the AA’s figure for the average Kiwi driver (11,500km). EV owners will pay $76 per 1000km in RUCs from April 1, implying $836 a year in RUCs. There will also be a $12.44 (online) or $13.71 (over the counter) admin fee each time you buy a block of RUCs.
The Clean Car Discount, phased out on December 31 last year, was not factored into the report’s sums.
The authors say they allowed for batteries degrading over time.
The report says an EV produced in China (home to most of the world’s electric vehicle production, including a giant Tesla plant) creates 12.3 tonnes of carbon dioxide emissions (6 tonnes for the vehicle and 6.3 for the battery). A petrol car’s manufacture involves an average 6.7 tonnes of CO2 emissions. Both figures are drawn from a European Federation for Transport and Environment study.
But it says that given New Zealand’s “highly renewable grid”, an EV will emit about 0.26 tonnes of CO2 a year if it drives 11,000km a year, and a petrol car about 2.58 tonnes a year — meaning an electric car will make up its greenhouse gas deficit within two years.