Leaf vs petrol hatch: what RUCs actually cost a Canterbury driver

The RUC exemption for light EVs is gone. We run the real numbers on a used Nissan Leaf versus a comparable petrol hatchback for a driver doing average annual kilometres in Canterbury.

The used Nissan Leaf has been one of the better-value cars available in New Zealand for the past several years. Cheap to buy, cheap to run, easy to live with in a city. The RUC exemption made the running-cost argument almost unanswerable. That argument has now changed, and it is worth being straight about by how much.

Pick up a 2017-2018 Leaf with a 30 kWh battery from a reputable dealer and you are probably spending $14,000-$18,000 depending on condition and battery health. A comparable petrol hatchback, say a 2017-2019 Toyota Corolla or Mazda Axela, sits in the $15,000-$20,000 range. The purchase price is close enough that it doesn't settle the argument on its own.

Running the numbers honestly

Take a Canterbury driver doing 12,000 kilometres a year. That is roughly the national average and a fair working assumption.

For the Leaf, RUCs at the current $76 per 1,000 km come to $912 a year. Home charging on a standard Christchurch electricity tariff of around 32-35 cents per kWh, assuming the 30 kWh battery and roughly 7.5 km per kWh in real-world mixed driving, works out to roughly 4.5 cents per kilometre. Over 12,000 km, that is $540 in electricity. Total energy and road-tax cost: around $1,450 a year.

For the petrol Corolla, petrol at $2.70 per litre and a real-world consumption figure of about 7.5 litres per 100 km gives you roughly $2,430 a year in fuel. No RUCs on a petrol car; that cost is wrapped into the fuel excise. WoF and registration costs are similar for both. Servicing is where the Leaf pulls ahead again: no oil changes, no timing chain, fewer consumables. Budget maybe $200-$300 a year for the Leaf versus $600-$800 for the Corolla across a full service schedule.

Net result over a year: the Leaf still saves money, but the margin has compressed considerably. Where a Leaf owner might once have been $2,000 or more ahead annually on running costs, the realistic gap now is closer to $800-$1,000. Over five years, that is still real money. But it is no longer the slam-dunk it was when RUCs were zero.

Where the Leaf's case gets complicated

The numbers above assume the battery is performing well. A 2017 Leaf with 80,000 km on it may be down to 70-75% of its original capacity. In Canterbury in winter, that means real-world range of 130-160 km from a full charge rather than the 200 km the spec sheet once suggested. If you are regularly driving Christchurch to Darfield and back, or commuting through Rolleston with a detour, you are watching the battery percentage in a way a Corolla driver simply isn't.

Battery degradation is the thing used Leaf buyers underestimate most consistently. A car showing ten out of twelve battery bars is fine. Anything at eight bars or below and you are buying a short-range city car, full stop. Check the battery health report before you commit, and factor in that a replacement 30 kWh pack, if you ever needed one, would cost more than many second-hand Leafs are worth.

The newer 40 kWh Leaf (2018 onwards, typically $20,000-$25,000 used) improves the range picture substantially and holds battery health better. The numbers above tilt more favourably with the larger pack, and the RUC cost doesn't change.

What this means for the buying decision

The Leaf still makes sense for a lot of Canterbury buyers. If you are driving 10,000-15,000 km a year, mostly in and around Christchurch, home-charging overnight, and you pick up a sound car with good battery health for under $17,000, you will likely come out ahead of an equivalent petrol car over a three-to-four year ownership period. The sums work, just less dramatically than they did before April 2024.

What has changed is the headroom. The RUC exemption used to mean that even a mediocre EV ownership experience, a slightly degraded battery, a slow home charger, the odd public charging hassle, could still be justified on pure economics. That buffer is thinner now. You need the car to actually suit your driving patterns, because the running-cost advantage alone won't carry a poor fit.

The petrol hatchback case is also stronger than it was when fuel was pushing $3.20 a litre. At current pump prices, a fuel-efficient petrol car is cheaper to run than it has been in a while. A well-bought Corolla or Axela with a full service history is a straightforward ownership proposition with no infrastructure dependencies and no battery anxiety.

Neither answer is wrong. But the Leaf is no longer the obvious one.