Car distributors’ organisation says Consumer NZ failed to remind petrol-electrics still performed better than fully fossil-fuelled equivalents.

DOUBT raised by the household name national consumer advocacy organisation about the efficiency of hybrid cars – a technology many Kiwis now favour - has triggered reaction from the organisation speaking for most new vehicle distributors.

Consumer New Zealand’s damning indictment of hybrids - the highly popular category of cars and sports utilities which match petrol engines with an electric motor for improved efficiency - was shared with media yesterday.

Among the 10 vehicles assessed by the watchdog organisation was the Toyota RAV4 (above), last year’s top-selling hybrid car.

In addition to provisioning the hybrid edition Kiwis are familiar with, Toyota New Zealand also supplied Consumer NZ with one it wants but has previously said it cannot secure for sale - a plug-in hybrid model called the RAV4 Prime.

The Motor Industry Association has reacted to Consumer’s conclusions, saying its findings overlook that the actual fuel economy from the test subjects was still very low and impossible to achieve in a conventional-engined vehicle.

“Even though Consumer NZ did not test conventional-engined vehicles, the reality is they would have also used more fuel than the official figures under the same conditions,” says MIA chief executive David Crawford.

A non-profit independent which promotes itself as the country’s most trusted source of independent consumer information, Consumer drew its conclusion from having recently trialled eight distributor-shared cars – four from Toyota, two from Kia and the remainder from Ford and MG - and using data about from a 2021 test of two versions of a Hyundai which is in runout.

It compared the outcomes it saw with the official optimal fuel economy figures that makers are required to display with new cars.

That data mainly comes from a economy and emissions test used widely (but not wholly) around the world called WLTP (Worldwide Harmonised Test Procedure). It introduced in 2018 to replace a previous protocol, NEDC (New European Driving Cycle) found to be less accurate. NEDC also still influences here.

The tests are important to Government’s Clean Car legislation, which sets penalties and rebates based on emissions, but exhaust outputs were not considered by Consumer – it was solely focused on economy.

It’s determination that the plug-in hybrid cars it tested used 73 percent more fuel than claimed, while standard hybrids averaged 20 percent more was based on a road trial that lacked the rigour of the WLTP regime.

This involved driving all around Wellington along the same route in rush hour traffic, as well as a supermarket run. It also took them on a longer weekend trip over the Remutaka Hill, a 14km connection between Wellington and the Wairarapa and one of the steepest roads in the lower North Island.

While advising it was “important not to sensationalise those figures – it’s not robust science,” the organisation nonetheless said in its report, and then on a prime time network news item, that it believed the technology isn’t living up to manufacturers’ fuel efficiency claims.

Crawford said the conclusions overlook that the actual fuel economy from the test subjects achieved was still very low – ranging from 1.4 litres per 100km to 3.1 litres per 100km, depending on model.

“These are still very low fuel consumption figures, lower than a hybrid and impossible to achieve in a conventional-engined vehicle.

“Even though Consumer NZ did not test conventional-engined vehicles, the reality is they would have also used more fuel than the official figures under the same conditions.”

The MIA also notes that car manufacturers don’t “claim” that their cars will achieve the fuel economy stated in the test results.

“Manufacturers are required to undergo these strict regulated lab tests, and to publish the results, including here in NZ,” Crawford says.

“Manufacturers explicitly state that drivers will potentially experience different fuel economy than that stated on the fuel economy labels.”

WLTP incorporates more scenarios likely to be similar to those used in real-world driving, but though some consumers consider it as a gospel, the industry warns it should not be seen as a guaranteed probability.

WLTP doesn’t account particularly well for traffic and weather conditions or behaviour – that one person might accelerate harder, take corners faster or brake more suddenly than another, who might drive more conservatively.

“The purpose of laboratory testing is to compare the fuel economy of vehicles under identical driving conditions. A car consuming more fuel in the lab test compared to another model, can be expected to use more fuel than the other car in the real world too.

Exactly how much fuel a car will use in the real world, will be different from that in the lab test, Crawford says.

“That’s because there are too many variables that affect how much fuel a car will use. These include driving style, traffic volumes, terrain, tyre pressure, vehicle condition, loads and even the weather.

“The bottom line is, each person’s day-today driving is unlikely match strict lab conditions. But in terms of fuel used, the Consumer NZ tests show that PHEVs are the most fuel-efficient type of vehicle people can buy if they want to reduce their fuel use.”

Toyota New Zealand, which dominates the hybrid sector, supplied three hybrid cars it has on sale here - the Yaris city hatch and the RAV4 and Highlander crossovers – plus a RAV4 with PHEV, generally marketed as the RAV4 Prime. It’s a car TNZ has had interest in for a while to supplement the RAV4 Hybrid, the country’s best-selling petrol-electric last year and subject to a long waiting list.

Also run were three compact to medium crossovers, the Kia Niro, in hybrid and PHEV formats, and PHEV editions of the Ford Escape and MG HS.

Consumer also involved the Hyundai Ioniq medium hatchback (not to be confused with Ioniq 5, a fully electric car), but relied on data it gained from driving that car in 2020, in its hybrid and PHEV formats. The Ioniq hatch has just been retired from sale.

Consumer said among the five PHEVs tested, the Niro used more than double (163 percent) the 0.8L/100km that its manufacturer claimed. The Ioniq used up 92 percent more than the 1.2L/100km it was estimated to use.

When it came to fully hybrid vehicles, the Yaris ZR saw the biggest discrepancy — up 44 percent of the 3.6L/100km it was estimated to use.

Consumer researcher James le Page told TV1’s evening bulletin that while some variation was not unexpected it was "staggering" to see how big it was in some cases.

“The (manufacturer) claims they put out there are all based on laboratory testing; in the real world, you would expect a little bit over... but 73 percent over, those are big numbers.

“It's good information for consumers to know that you're probably not going to get what they say you are going to get, especially if you do long road trips in plug-in-hybrids.”