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PHEVs release almost 5x greater planet-heating emissions than lab-reported data indicate, as per a recent report.

Growing Gap In Lab and Actual CO2 Output

Data shows that PHEVs emit only one-fifth less CO₂ than traditional petrol and diesel cars, based on research carried out by a advocacy group. That differs sharply with lab tests, which suggested a three-quarters decrease in pollution.

Researchers studied data from onboard fuel consumption meters of 800,000 cars registered in the EU from 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, up from three and a half times in 2021.

“Real-world emissions are increasing, while official emissions are decreasing,” stated a senior researcher participating in the study. “That gap is growing and creates a serious issue. As a result, PHEVs pollute nearly as much as petrol cars.”

Key Reasons Behind the Emissions Gap

Analysts attributed most of the difference to overestimates of the “electric driving share” – the ratio of miles driven in battery mode relative to total distance. The team found that just 27% of travel was done in electric mode, while lab estimates assumed over four-fifths.

Even, when running in EV mode, emission amounts were significantly higher than official estimates. That happened because EV motors were not strong enough to operate alone, leading to engines burning gasoline for nearly a third of the distance covered in electric mode.

Regulatory and Economic Consequences

According to calculations, the underestimation of PHEV emissions enabled four large automaker companies to escape more than €5bn in penalties between 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs would pay approximately €500 more per year in operating costs than would be assumed under lab tests.

“The bold statements that manufacturers like to make about their plug-in hybrid vehicles are clearly way off the truth,” commented a automotive analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. Actually, PHEVs are only slightly better than regular gas and diesel vehicles in terms of energy use, CO₂ emissions, and operating expenses.”

Political Debate and Automotive Lobbying

Hybrid vehicles have lately been drawn again into policy discussions as carmakers have pressed the EU to relax CO₂ targets. A proposed prohibition on new combustion engine cars in 2035 has faced intense lobbying from the car sector and opposition from member states with large automotive industries.

Several high-level politicians have suggested plug-in hybrids as a possible “compromise” solution to include in the legislation.

An external energy policy specialist, who was unaffiliated with the study, called the report a “highly valuable addition” after years in which segments of the car industry argued there was too little data to accurately evaluate actual CO2 output.

“The results demonstrate, without question, that the gap between official and real-world PHEV energy use and CO₂ emissions is much, much larger than for petrol or conventional vehicles,” they said. “Any policy changes concerning PHEVs should be made with utmost caution and considering this data.”