Plug in Hybrid Vehicles Pollute Almost as Heavily as Petrol Vehicles, Study Finds

Plug-in hybrid cars produce nearly five times greater planet-heating emissions than lab-reported data show, according to a new report.

Widening Gap In Lab and Actual Emissions

Statistics shows that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel vehicles, according to research conducted by a advocacy group. This contrasts significantly with lab tests, which suggested a three-quarters reduction in emissions.

Analysts examined data from in-vehicle energy use monitors of eight hundred thousand vehicles registered in Europe between 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are falling,” stated a senior researcher involved in the study. “This gap is growing and creates a serious issue. Consequently, PHEVs emit nearly as much as petrol vehicles.”

Key Factors Behind the Discrepancy

Researchers linked most of the gap to overestimates of the “electric driving share” – the percentage of miles driven in electric power relative to overall mileage. They determined that just 27% of travel was done in EV mode, whereas official estimates assumed over four-fifths.

Even, when operating in EV mode, pollution levels were well above official estimates. This occurred because electric motors were not strong enough to operate independently, resulting to combustion motors using gasoline for nearly one-third of the distance covered in electric mode.

Policy and Financial Consequences

According to estimates, the lowballing of PHEV emissions allowed several large automaker companies to escape more than €5bn in fines from 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ standards.

Additionally, drivers of PHEVs would pay about €500 extra per year in running costs than is estimated under laboratory conditions.

“The bold statements that automakers like to make about their plug-in hybrid vehicles are obviously way off the truth,” commented a automotive expert. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little better than standard gas and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Political Discussion and Automotive Lobbying

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

Several high-level politicians have proposed PHEVs as a potential “compromise” option to introduce in the regulation.

An independent energy policy expert, who was not involved with the study, described the report a “very useful contribution” after a long period in which segments of the car sector argued there was insufficient information to accurately assess actual emissions.

“The results show, without question, that the difference between official and real-world PHEV energy use and CO₂ emissions is much, much larger than for gasoline or conventional cars,” the expert said. “Any regulatory changes regarding PHEVs should be implemented with utmost care and in the light of this data.”