PHEVs ‘most fuel-efficient’

The Motor Industry Association (MIA) has spoken out about a Consumer NZ test of plug-in hybrid vehicles (PHEV) and hybrids, which took aim at the “real-life” fuel use of such models.

The study in Wellington found both types of powertrains used more fuel than the manufacturers’ so-called “claimed” fuel consumption.

David Crawford, MIA’s chief executive, issued a response to the findings and notes the tests also show PHEVs are the most fuel-efficient vehicles with a conventional engine.

“Overlooked in those test results was that the actual fuel economy achieved was still very low – ranging from 1.4 litres per 100km to 3.1 litres per 100km, depending on model,” he explains. 

“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 notes car manufacturers don’t “claim” their cars will achieve the fuel economy stated in the test results, but they are required by law to undergo strict regulated lab tests and to publish the results. 

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

“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.”

He continues that how much fuel a car will use in the real world will be different from that in a lab test because there are many variables that affect fuel consumption.

These include driving style, traffic volumes, terrain, tyre pressure, vehicle condition, loads and even the weather. 

“The bottom line is, each person’s day-to-day driving is unlikely to 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,” says Crawford.