By Eloise Gibson of RNZ
Changes to road user charges are a “leap into the unknown” and will increase New Zealand’s emissions, a researcher says.
Massey University mathematics professor and climate writer Robert McLachlan said the current petrol tax paid by drivers was the equivalent of paying a carbon tax of $448 per tonne of emissions, more than four times New Zealand’s actual carbon price.
Right now there are two payment systems operating: road user charges (RUCs) which are levied by the kilometre on diesel vehicles and EVs, and a petrol tax paid for by the litre for petrol cars.
Dr McLachlan said the government’s plan to switch all drivers to paying per kilometre (not by fuel use) would reduce the disincentive to burn fossil fuels – and raise New Zealand’s carbon dioxide emissions.
Universal road user charges are proposed to start in 2027, changing the way drivers of the country’s more than 3 million petrol vehicles contribute to the cost of roads.
Dr McLachlan said Iceland was the only other country to be planning road user charges for all vehicles, and it was hard to compare Iceland to New Zealand because almost a fifth of cars in Iceland were EVs, compared with New Zealand’s 3%.
Iceland also had a higher carbon price and planned to ban sales of petrol cars from 2030.
Dr McLachlan said moving to RUCs would increase taxes on the drivers of the country’s 300,000 or so non-plug-in hybrid vehicles, including fuel-efficient models such the Toyota Prius or Aqua.
“It’ll increase the cost of driving a low emissions vehicle and I suspect there’ll be a lot of angry hybrid drivers.”
He calculated it would increase the running costs of the lowest-emitting hybrids by 39% – while lowering by 6% the cost to run the most gas guzzling petrol cars, models that burn 10 litres or more of fuel per 100km.
“This could have a big effect on emissions from road transport and transport is the largest single source source of fossil fuel burning in New Zealand, so doing things now or in 2027 that are going to increase emissions is exactly the wrong way to where we should be going.”
But not everyone agreed the new system would increase carbon dioxide emissions.
That was because since EVs came into the RUC system in 2024, EVs have paid more in taxes for the equivalent amount of driving than efficient, small petrol cars and non-plug-in hybrids.
The existing mixed system penalised full EVs in favour of efficient, small petrol cars and non-plug-in hybrids like the Prius, which currently pay less tax per kilometre than EVs of a similar size and model.
Motoring groups dubbed the anomaly a “penalty on a plug” – and warned it would put people off EVs until all vehicles were under the same RUC system.
Mike Casey, of climate and electrification charity Rewiring Aotearoa, said the current system was a “sweetheart deal” for non-plug-in hybrids. He said only EVs, not efficient petrol cars, could achieve big enough carbon savings to solve the country’s road transport emissions problems.
“If we want to be carbon zero or net zero in 2050, fuel efficiency will not get us there. We have to get off the fossil fuels in the first place,” he said.
Rewiring’s calculations showed that once all cars were under the RUC regime, fully electric cars would once more be the cheapest option to drive, overtaking small hybrids once more.
Casey said the calculations showed that the only petrol cars that would pay less tax under universal RUCs were “bogan cars” – gas guzzlers like the Ford Mustang V8.
He said those cars’ owners were not sensitive to high running costs, or they would not have such thirsty vehicles in the first place.
“For the large majority of cars they are not V8 Commodores or Falcons or Mustangs, they are just normal RAV4 and Kia Sportages and things like that and the price of those is all going up.”
EV sales have plunged since the end of feebates and the advent of RUCs for electric cars.
Casey said levelling the playing field so all vehicles paid RUCs by the kilometre was good, but EVs would only truly take off if people had better access to affordable finance to buy them, and reliable fast public chargers.
How universal RUCs will change the cost of driving for someone driving an average distance of 11,000km per year (including fuel/electricity and RUC).
Source: Rewiring Aotearoa
• Ford Mustang V8 petrol – decrease $117 a year
• Ford Ranger diesel ute – no change
• Mitsubishi Outlander 4WD – increase $139 a year
• Toyota RAV4 petrol – increase $211 a year
• Toyota RAV4 hybrid – increase $372
• Toyota Corolla petrol – increase $303
• Toyota Aqua Hybrid – increase $474
• Seven-seater Kia EV9 AWD electric vehicle – no change .
• Tesla Model Y AWD – no change
(Both the Kia EV9 AWD and Tesla Model Y save around $1000 per year on RUCs and fuel/electricity combined compared to equivalent petrol vehicles).
