EV and hybrid running costs after NZTA's new RUC rates: do the sums still work?

NZTA's updated RUC rates for light EVs are now in effect. We break down what Leaf and Aqua owners in Canterbury are actually paying per kilometre against petrol equivalents.

The argument for running a Nissan Leaf in Canterbury has always rested on a specific kind of maths: buy the car cheap enough, charge it at home on an overnight rate, and the per-kilometre cost undercuts everything else on the road. That argument has taken a knock this month.

NZTA's new RUC rate for light EVs sits at $76 per 1,000 kilometres, up from $53. If you are driving 30,000 kilometres a year in a Leaf, you are now paying $2,280 in road user charges annually. Last year that figure was $1,590. The gap matters.

What the Leaf is actually costing per kilometre now

A 40kWh Leaf, which covers the bulk of the used stock arriving here from Japan, uses roughly 16 to 18kWh per 100 kilometres in real-world Canterbury conditions. Factor in winter heating load and older battery degradation, and 18kWh/100km is the honest number for a 2018 or 2019 model.

At a home overnight electricity rate of around 28 cents per kWh, that is about 5 cents per kilometre in energy cost. Add the new RUC at 7.6 cents per kilometre, and you are sitting at roughly 12.6 cents per kilometre before you touch insurance, tyres, servicing, or WoF.

For comparison, a petrol equivalent in the same commuter bracket, say a 2018 Toyota Corolla hatch, uses around 6.5 to 7 litres per 100 kilometres. At $2.80 per litre of 91, that is 18.2 to 19.6 cents per kilometre in fuel alone, already well above the Leaf's all-in energy and RUC figure. The Corolla also pays its road tax at the pump, invisibly, which is part of why the RUC conversation feels unfair to EV owners even when the absolute numbers still favour them.

The Leaf still wins on running cost. The margin has narrowed, but it has not flipped.

Where the Aqua hybrid sits

The Toyota Aqua is the more relevant comparison for a lot of Canterbury buyers, partly because the supply is steady, the reliability record is well understood, and the purchase price on a tidy 2015 to 2018 model sits in the $12,000 to $16,000 range, which is broadly where entry-level used Leafs have settled too.

The Aqua does not pay RUCs. It pays petrol tax embedded in the pump price. Real-world fuel consumption on a Canterbury commute, with some motorway and some suburban, comes in around 4.5 to 5 litres per 100 kilometres. At $2.80 per litre that is 12.6 to 14 cents per kilometre.

So at the low end, the Aqua and the post-RUC-increase Leaf are almost exactly matched on per-kilometre cost. That is a significant shift from eighteen months ago, when the Leaf held a clear 3 to 4 cent per kilometre advantage.

The real objection to declaring the Aqua the winner here is that electricity prices and petrol prices move in different directions at different times, and the Leaf owner has more control over their energy cost. Someone with solar panels, or who charges at work, is running the Leaf for energy costs close to zero and paying only the RUC. That driver's per-kilometre cost drops to around 7.6 cents. Nobody in a petrol car is getting close to that.

The high-mileage question

For the commuter doing 35,000 kilometres a year, here is how the annual running cost comparison looks in round numbers, covering energy or fuel plus RUCs or embedded road tax, and nothing else.

Leaf 40kWh at home charging: roughly $6,160 combined. Aqua hybrid at current petrol prices: roughly $4,900 to $5,400. Corolla petrol: roughly $6,400 to $6,800.

The Aqua has moved into a genuine cost advantage over the Leaf at high mileage, which was not true before August. The gap is not enormous, around $800 to $1,200 per year depending on your electricity rate and how degraded the Leaf's battery is. But over three years of ownership that is $2,400 to $3,600, and that is enough to matter to most people buying in the $12,000 to $16,000 bracket.

Frankly, the case for the Leaf at high mileage now depends heavily on your charging setup. If you are paying standard residential rates and have no access to workplace charging, the numbers have softened to the point where the Aqua is the rational choice unless you specifically want the EV experience or have range that the Aqua cannot cover.

The Leaf still makes sense for the moderate-mileage driver doing 15,000 to 20,000 kilometres a year, where the lower fixed RUC cost and home charging advantage preserve a meaningful gap. And it makes obvious sense if you have cheap electricity.

For my money, the more interesting consequence of this RUC increase is what it does to used Leaf prices over the next six months. Buyers do this maths, eventually. If enough of them decide the sums no longer flatter the Leaf, the $12,000 to $14,000 asking prices currently sitting on Trade Me will start to look ambitious.