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Plug-in hybrid electric vehicles emit nearly 5x more planet-heating pollution than official figures indicate, as per a recent analysis.

Growing Discrepancy In Official and Actual CO2 Output

Data reveals that PHEVs emit just one-fifth less CO₂ than traditional petrol and diesel cars, according to research conducted by a non-profit group. This contrasts significantly with laboratory tests, which suggested a three-quarters decrease in pollution.

Researchers studied information from in-vehicle fuel consumption meters of 800,000 vehicles sold in Europe from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official figures are falling,” stated a lead researcher participating in the report. “This discrepancy is widening and poses a significant problem. Consequently, PHEVs emit nearly as heavily as gasoline vehicles.”

Primary Factors Behind the Discrepancy

Researchers linked most of the difference to overestimates of the “electric driving share” – the ratio of kilometers travelled in battery power relative to total mileage. The team found that only 27% of driving was done in electric mode, while lab estimates assumed 84%.

Even, when operating in EV mode, pollution levels were well above official estimates. That occurred because EV motors were not strong enough to function alone, resulting to engines using fossil fuels for nearly a third of the distance covered in EV mode.

Policy and Economic Consequences

Based on calculations, the underestimation of PHEV emissions enabled four large automaker companies to escape over €5bn in fines between 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ targets.

Additionally, owners of PHEVs could spend approximately €500 extra annually in operating costs than would be estimated under laboratory conditions.

“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are clearly way off the mark,” stated a automotive analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and cutting money. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of fuel use, CO₂ production, and operating costs.”

Political Debate and Industry Lobbying

Hybrid cars have recently been brought again into political discussions as carmakers have pressed the European Union to relax CO₂ targets. A planned ban on sales of new combustion engine cars in 2035 has faced intense pressure from the car industry and opposition from member states with large automotive industries.

Some high-level politicians have proposed plug-in hybrids as a potential “compromise” option to include in the regulation.

One independent energy economics specialist, who was not involved with the study, described the analysis a “very useful contribution” after a long period in which parts of the car industry argued there was too little data to properly evaluate actual CO2 output.

“The results demonstrate, without question, that the gap between official and actual PHEV fuel consumption and CO₂ emissions is significantly larger than for petrol or conventional vehicles,” they said. “All regulatory changes regarding PHEVs should be implemented with utmost care and in the light of this evidence.”