Amid mounting evidence that we are not facing anthropogenic climate doom [1], there has been some relaxation in the push to legislate fossil-fuel powered vehicles off the roads over the next 10 years [2]. But let’s not kid ourselves that fossil fuels are an unlimited resource on human time scales. Their replacement in the Earth’s crust requires geological events over tens of millions of years.
So, I am on board with the FIA mandating “sustainable” fuels for Formula 1 motor racing in 2026, but they should get rid of the roughly 50% electric power (400 kW from the internal combustion engine and 350 kW from the electric motor) and let drivers be out-and-out racers not battery managers. But, what about the private motorist?
It is inevitable that a time will come, many years hence, when fossil fuels are largely reserved for aircraft, heavy transport, shipping and petrochemical industries. Biofuels and other sustainable fuels may offer some respite, but these tend to be expensive and their production in some cases environmentally damaging. In the future, we may see more liquid fuel from coal and gas conversion plant like the South African SASOL systems [3], but such fuel would only power a small part of the world vehicle fleet.
The electric vehicle (EV) fleet will continue growing but, for EVs to quickly dominate the fleet, we need:
(i) New battery technology that is cheaper and more environmentally friendly: There is also the current issue that a substantial proportion of necessary lithium and cobalt raw materials are mined under unethical near-slave labour conditions.
(ii) Substantially expanded capacity in the main power grid: New Zealand power prices are rising well ahead of inflation (15.2% Q1 2023 to Q2 2025) because of long-term under investment in infrastructure and the need for urgent capital works. There is also the pressing issue of building additional generation capacity, and as discussed previously [4], this cannot be done with just wind and solar power without driving consumer electricity prices sky high and risking blackouts. A substantial and rapid increase in the EV fleet would place unacceptable pressure on the grid unless EV charging were restricted to certain times of day, or, for example, to domestic roof-top solar charging systems with all the attendant supply uncertainty that involves.
A different Fossil Fuel Vehicle Fleet Composition?
One possible bridging strategy is to reshape the make-up of our internal combustion engine vehicle fleet for lower petrol and diesel fuel use. The Iran War, fuel price hikes and potential supply strictures have brought our weak fuel supply chain resilience into stark relief. Many have rushed out to buy an EV, but could have equally bought a Fiat 500 or Toyota Yaris and left the big SUV in the garage for trips down country.
Living half-time in France, I am aware that the typical French car is smaller in size with lower power than the typical car in NZ. I am always struck on returning to NZ by the masses of large vehicles on the road. We have lots of hulking Toyota, Mitsubishi, Nissan, Ford, Audi, Volkswagen, Mercedes Benz SUVs and other equivalents doing the daily school run, the often-present 4WD capability rarely, if ever, used.
Whereas in France it is very unusual to see a C or E type Mercedes Benz with more than a modestly powered 1.9 - 2.1 litre engine, it is common in NZ to see high-powered models like the C43 and even more powerful C63S AMG models, and the larger equivalents in the E and S range. Similar comparisons apply across most vehicle brands, except of course your typical Citroen, Peugeot or Renault.
In France, vehicles are taxed on an administrative value called chevaux fiscaux (CV) or fiscal horsepower. This number is calculated from technical characteristics of the vehicle, including:
· Engine power in kW
· CO₂ emissions (for older NEDC‑tested vehicles prior to 2019)
· A standardized formula depending on the vehicle’s homologation cycle.
In New Zealand, there is no vehicle tax that relates to engine power, although the diesel-only vehicle Road User Charges (RUC) formula does include vehicle weight, which is loosely correlated with vehicle power. Consequently, there is little incentive for New Zealand buyers to choose a vehicle with a smaller engine capacity and lower weight unless the buyer is actively thinking about saving on fuel cost.
Including rental cars and taxis, NZ has a fleet of over three million cars and 750,000 trucks. While ownership of trucks is largely dictated by trades or freight-carrying user needs, car owners are much more likely, apart from the basic size requirement, to choose a car simply for performance, as a fashion accessory, or as a status symbol.
Why does any of this matter?
Energy Consumption and the Benefit of Smaller Cars
Over 1987-1988 we carried out a project at the University of Canterbury in computer modelling of vehicle energy consumption, which at lower speeds typical of city motoring closely correlates with vehicle mass, with aerodynamic drag becoming more important above 70 km/h and much more at open road speeds. Modelling showed that on prevailing urban emissions test cycles, about 90% of the fuel energy used was consumed in accelerating the loaded vehicle mass up to speed.
Let’s compare some numbers between France and NZ.
In New Zealand average engine size is ~2.4 litres versus ~1.5 litres (a little higher for diesels) in France. The Australian fleet is similar in make-up to NZ, while the USA of course eclipses both France and Australasia on both vehicle and engine size. Whereas the average car power output is about 88 kW in France, there is no official average figure for NZ, but it is likely that the average car (including SUVs) power output would be approaching 140 kW, perhaps 60% more than in France.
The average loaded weight of a car (including SUVs) in NZ would be unlikely to be 60% higher than in France but let us estimate, conservatively, that it is ~25% higher. Moreover, drivers of high-powered vehicles inevitably burn more fuel simply because the power is available for acceleration. Most of the NZ car fleet would be used in predominantly urban driving. On this basis, if our fleet were comprised as in France, NZ could contemplate ~30% reduction in its urban running fuel bill, maybe more. Smaller savings would accrue with open road motoring.
The New Zealand car fleet consumes 4 – 5 billion litres of petrol and diesel each year. So, inferring roughly from the figures above, an overall annual saving of well over one billion litres could ultimately be achievable. Looks useful when we have a long-term limited fuel resource or a disrupted supply chain.
Taxing the overall car fleet with an RUC formula strongly based on vehicle mass and power would encourage people into smaller, lighter vehicles with lower power output. They would face lower first purchase costs and substantially lower lifetime fuel costs.
Vehicle Owner’s Choice but Government Could Incentivise Change
You might see all this as either kill-joy number crunching or irrelevant, given the gradual electrification of the car fleet. However, because of very real resource limitations for EV batteries and the lack of capacity of the current main power grid to handle a vastly increased vehicle battery charging load as outlined above, fossil-fuelled vehicles will comprise much of the fleet for many years yet.
It would take some time after the introduction of even aggressive tax incentives favouring generally smaller, lower-powered fuel-miserly vehicles for the fleet composition to change substantially. And yes, of course there would be consumer resistance, plenty of owners still opting to pay the tax to buy a bigger, more powerful car.
Finally, it is easy to be caught out in hypocrisy on all of this. My vehicle in France is an economical 1.6 litre diesel Renault Megane estate car whose 97kW engine has ample power for good acceleration and effortless high speed motorway travel. But…in NZ I own a high-powered car capable of quickly cancelling a driving licence. There is no rational justification for this, but in its defence the NZ car very rarely gets out of the garage.
Personal inclinations and work needs will still be important in the car purchase equation, but adopting a form of the French vehicle tax system would be good for the environment, reduce vehicle purchase costs and the national fuel bill, deliver knock-on economic benefits, and increase resilience to fuel supply chain disruption. Worth a try, isn’t it?
John Raine has been a car nut from an early age. He worked as a mechanical engineer in the UK engine and vehicle test plant industry, and subsequently in academia in NZ. His PhD was in wind energy, and his later research was for a time in alternative energy for both vehicles and domestic homes.
References
1. Roger Pielke Jr, “RCP8.5 is Officially Dead” The Honest Broker, Substack, 29th April 2026. https://substack.com/home/post/p-195733015
2. RFI, “EU Rolls Back 2035 Petrol and Diesel Car Ban Amid Industry Pushback. 17th December 2025 https://www.rfi.fr/en/international/20251217-eu-rolls-back-2035-petrol-and-diesel-car-ban-amid-industry-pushback?utm
3. SASOL https://en.wikipedia.org/wiki/Sasol
4. John Raine, “Climate and Energy Policy Realism Not Virtue Signalling, Please”. Breaking Views NZ 26thFebruary 2026. https://breakingviewsnz.blogspot.com/2026/02/professor-john-raine-climate-and-energy.html#more
2 comments:
It is absurd how we have allowed ourselves to become so dependent on cars (and hence fossil fuels). Now cluttered with equipment; window winders, air con, power seat adjusters etc. Along with their manufacture, very wasteful. And in this country the macho American culture means that many drive vehicles much larger than their needs; Ford Rangers, enormous tyred 4wd, huge cars etc. The legal seating requirements, esp for children, another factor.(With two bench seats grandparents could convey 5 or6 plus 3 or 4 children on knees. Now can only carry 4 or 5 total of any age. And 100-110 kph cruisng speeds which make little point to point difference on any typical journey involving traffic lights etc have been encouraged. In the 1950s a single Morris Minor or equivalent was considered adequate by many young families; now the same run two cars, both vastly larger. We should be encouraging the long term use of vehicles, such as the recent 2 million km Toyota, to minimise energy costs associated replacement and transport here. If we could tolerate the modest performance of decades ago fuel mileages markedly better than the typical modern acheivable. Prohibitive fuel costs are the only real deterrent to use. But we attempt to mask these by encouraging general inflation so little real deterrent.
Very insightful John, and the inevitable outcome once the penny finally drops at Government level. And in anticipation of that, the smart money should now be investing in the small car industry.
Post a Comment
Thank you for joining the discussion. Breaking Views welcomes respectful contributions that enrich the debate. Please ensure your comments are not defamatory, derogatory or disruptive. We appreciate your cooperation.