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Plug-in hybrid cars release nearly 5x greater planet-heating pollution than official data indicate, as per a recent report.

Widening Gap Between Official and Real-World Emissions

Data reveals that PHEVs emit just one-fifth lower CO₂ than traditional petrol and diesel cars, according to research conducted by a non-profit organization. That differs sharply with laboratory tests, which assumed a three-quarters decrease in pollution.

Researchers examined information from onboard fuel consumption meters of eight hundred thousand vehicles sold in Europe from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are falling,” stated a senior researcher involved in the report. “This gap is widening and creates a serious issue. Consequently, PHEVs pollute nearly as much as petrol vehicles.”

Key Factors Behind the Discrepancy

Researchers attributed the majority of the difference to inflated estimates of the “electric driving share” – the ratio of miles travelled in electric power compared to overall distance. They found that just 27% of driving was done in EV mode, while lab estimates assumed over four-fifths.

Even, when running in electric mode, emission levels were significantly higher than official estimates. That occurred because EV motors were not strong enough to operate alone, resulting to combustion motors using gasoline for almost one-third of the distance covered in electric mode.

Regulatory and Economic Implications

According to calculations, the underestimation of PHEV emissions allowed four large carmaker companies to avoid over €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Additionally, owners of PHEVs could pay about €500 more annually in running expenses than is estimated under laboratory conditions.

“The strong claims that automakers like to make about their PHEV cars are clearly way off the mark,” stated a automotive expert. “Buyers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are little better than standard gas and diesel cars in terms of fuel use, CO₂ production, and running expenses.”

Policy Debate and Automotive Lobbying

Plug-in hybrid cars have lately been brought again into political debates as carmakers have lobbied the European Union to relax CO₂ targets. A proposed ban on new combustion engine cars in 2035 has faced heavy pressure from the car industry and opposition from member states with significant car manufacturing.

Several high-level officials have proposed PHEVs as a potential “flexibility” solution to introduce in the regulation.

An independent energy economics specialist, who was not involved with the study, described the report a “highly valuable contribution” after years in which parts of the automotive sector argued there was too little data to properly evaluate actual emissions.

“The results demonstrate, without question, that the gap in official and actual PHEV energy use and CO₂ emissions is much, much larger than for gasoline or diesel cars,” the expert stated. “Any policy adjustments concerning PHEVs should be implemented with extreme caution and in the light of that evidence.”