What EVs actually cost per kilometre once RUCs hit your wallet

RUC charges on light EVs are now a real ongoing cost. We crunch the numbers on Leaf, MG ZS EV and BYD Atto 3 against a petrol Aqua and hybrid CX-5 to find out what you actually pay per kilometre.

A 2019 Nissan Leaf with 60,000km on it sits on used-car lots around Christchurch for somewhere between $19,000 and $24,000. An MG ZS EV from the same era is a few thousand more. A BYD Atto 3 from 2022-23 is pushing $36,000-$42,000. Against those, a 2020 Toyota Aqua hybrid will set you back $16,000-$20,000, and a 2019 Mazda CX-5 petrol or diesel sits at $24,000-$30,000 depending on spec and kilometres. The sticker gap between EV and petrol still exists. The running-cost gap is narrowing.

Here is what the numbers actually look like when you lay them out.

The EV cost stack

Start with the Nissan Leaf. The 40kWh variant that dominates NZ used lots returns around 6.5-7km per kWh in real-world Canterbury driving, which means a 15,000km annual commute needs roughly 2,200-2,300kWh. At a home charging rate of 32 cents per kWh, that is about $720 a year in electricity. Add the RUC of $76 per 1,000km and you are paying $1,140 on top. Total energy and road-user cost: around $1,860 per year, or roughly 12.4 cents per kilometre.

The MG ZS EV has a larger 44.5kWh battery and is heavier, so efficiency is similar or slightly worse. Call it the same 12-13 cents per kilometre on home charging plus RUC. The BYD Atto 3, with its 60.5kWh battery and a kerb weight over 1,700kg, drinks more. Real-world efficiency sits closer to 5.5-6km per kWh. On the same 15,000km year, electricity alone runs to $850-$900, and the RUC adds the same $1,140. You are looking at around 13.3 cents per kilometre before you touch servicing, insurance or tyres.

Servicing is genuinely cheaper on EVs. No oil, no filters, no timing chain. Budget around $200-$300 a year for brake fluid checks, cabin filters and a decent WoF. After three years the WoF interval drops to annual, same as any other car. The Leaf's battery degradation is the well-known wild card: early 24kWh Leafs are mostly off lots now, but even 40kWh packs from 2018-2020 show capacity loss depending on charging history. A Leaf that shows ten out of twelve battery bars on the dashboard display is fine. Eight bars means your real-world range is 160km on a warm day and less in a Christchurch winter. Check the bars before you buy.

What petrol and hybrid actually cost

A 2020 Toyota Aqua runs a 1.5-litre Atkinson-cycle petrol engine paired to a nickel-metal hydride battery pack. Real-world consumption on Canterbury roads is around 4.5-5.0 litres per 100km. At $2.75 per litre, that is $618-$687 per 100km on fuel, or $6.18-$6.87 per 1,000km. Over 15,000km: roughly $928-$1,030 in petrol. No RUC on petrol vehicles. Servicing on an Aqua is cheap and parts are everywhere. Water pump and inverter coolant pump failures show up on higher-mileage cars, but they are not common. Call the total annual energy cost around $1,000-$1,050, or 6.7-7.0 cents per kilometre.

The Mazda CX-5 in 2.0-litre petrol form uses around 8.5-9.5 litres per 100km in mixed driving. At current pump prices that is $23.40-$26.00 per 100km, or around $3,500-$3,900 a year on fuel for 15,000km. No RUC. Servicing is reasonable and the 2.0 SkyActiv is a known quantity. The diesel SH-VPTS 2.2 is more efficient at 6.5-7.0L/100km but carries RUC at the light diesel rate ($76 per 1,000km, same as EVs), so the per-kilometre cost lands around 13-14 cents. The petrol CX-5 sits at 23-26 cents per kilometre on fuel alone. It is the big car of the comparison. You pay for the size.

Where the EV case still stands

On raw per-kilometre energy cost, the Aqua hybrid wins comfortably. It is genuinely the cheapest car to run in this group. An EV charged entirely at home at off-peak rates does come in lower than the Aqua on electricity alone, but once RUCs are in the total cost is close enough that the hybrid's lower purchase price often closes the gap entirely.

Where the EV still makes sense is for high-kilometre drivers who do the bulk of charging at home and rarely rely on public rapid chargers. If you are doing 25,000km a year in a Leaf, the fuel cost saving over a petrol CX-5 is real money: $2,500-$3,000 a year even after RUCs. At 15,000km, it is maybe $500-$700 against a hybrid. At 10,000km, the numbers barely move.

Buying a used EV because it used to be cheap to run, without redoing the sums post-RUC, is how people end up disappointed. The exemption is gone. The numbers are what they are. Work out your actual annual kilometres, look up your electricity rate, add $76 per 1,000km, and then compare. The Aqua will surprise a lot of people.