Plug in Hybrid Vehicles Emit Almost as Heavily as Petrol Cars, Study Finds

PHEVs produce nearly 5x more planet-heating emissions than official data show, as per a recent analysis.

Widening Gap Between Official and Actual CO2 Output

Statistics shows that PHEVs emit only 19% less CO₂ than traditional petrol and diesel cars, according to research carried out by a advocacy group. This contrasts sharply with lab tests, which suggested a 75% decrease in pollution.

Researchers examined information from onboard fuel consumption meters of 800,000 vehicles sold in Europe between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.

“Actual emissions are rising, while lab-reported figures are falling,” stated a senior analyst participating in the report. “That discrepancy is widening and creates a significant problem. Consequently, PHEVs emit almost as much as gasoline vehicles.”

Key Factors Driving the Emissions Gap

Analysts attributed the majority of the difference to overestimates of the “utility factor” – the ratio of miles travelled in electric mode compared to total mileage. The team found that only 27% of driving was done in EV mode, whereas lab assumptions assumed over four-fifths.

Additionally, when operating in electric mode, pollution levels were well above official estimates. That occurred because EV motors were not strong enough to function independently, resulting to engines using fossil fuels for nearly one-third of the distance completed in electric mode.

Policy and Economic Implications

According to estimates, the underestimation of PHEV CO2 output enabled four large automaker groups to avoid more than €5bn in penalties between 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs could spend approximately €500 more annually in operating expenses than would be assumed under lab conditions.

“The strong claims that manufacturers like to make about their PHEV vehicles are clearly far from the mark,” stated a automotive expert. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the planet and saving money. Actually, PHEVs are only slightly better than regular gas and diesel vehicles in terms of energy use, CO₂ production, and operating expenses.”

Political Discussion and Automotive Pressure

Plug-in hybrid vehicles have lately been brought again into policy discussions as carmakers have pressed the EU to weaken CO₂ targets. A planned ban on sales of new combustion engine cars in 2035 has faced intense lobbying from the car sector and opposition from member states with large car manufacturing.

Several high-level officials have suggested plug-in hybrids as a potential “flexibility” option to introduce in the regulation.

One independent energy economics specialist, who was not involved with the research, described the report a “very useful contribution” after a long period in which segments of the automotive sector claimed there was too little data to properly evaluate real-world emissions.

“The results show, without question, that the difference between official and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for gasoline or conventional cars,” the expert said. “All policy adjustments regarding PHEVs should be implemented with extreme care and considering this data.”