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Plug-in hybrid cars release almost five times greater planet-heating emissions than official figures show, as per a recent analysis.

Widening Gap In Official and Actual CO2 Output

Statistics shows that PHEVs release only one-fifth less CO₂ than traditional petrol and diesel cars, according to research conducted by a non-profit organization. This differs significantly with lab tests, which assumed a 75% decrease in emissions.

Researchers studied data from onboard energy use monitors of 800,000 vehicles registered in the EU between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official emissions are decreasing,” stated a lead analyst participating in the report. “That gap is growing and poses a serious problem. Consequently, PHEVs emit almost as much as petrol cars.”

Key Reasons Behind the Emissions Gap

Researchers attributed the majority of the gap to overestimates of the “electric driving share” – the ratio of kilometers driven in battery power relative to total distance. The team found that only 27% of driving was completed in electric mode, whereas official estimates assumed over four-fifths.

Even, when running in EV mode, pollution levels were significantly higher than official estimates. This happened because electric motors were insufficiently powerful sufficient to function alone, resulting to combustion motors burning fossil fuels for nearly one-third of the travel covered in electric mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV emissions allowed several major carmaker companies to avoid more than €5bn in fines between 2021 and 2023, by falsely simplifying adherence with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs could pay approximately €500 more per year in operating expenses than is assumed under lab conditions.

“The bold statements that manufacturers often promote about their PHEV cars are clearly far from the truth,” commented a transport expert. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little better than standard petrol and diesel vehicles in terms of energy use, CO₂ production, and operating costs.”

Political Debate and Industry Lobbying

Hybrid vehicles have recently been drawn again into political debates as carmakers have pressed the European Union to weaken CO₂ targets. A proposed prohibition on new combustion engine cars in 2035 has faced heavy pressure from the automotive industry and resistance from member states with significant car industries.

Some senior officials have suggested plug-in hybrids as a possible “flexibility” solution to introduce in the legislation.

An external energy policy expert, who was not involved with the study, called the analysis a “very useful contribution” after years in which segments of the car sector claimed there was insufficient data to properly assess real-world CO2 output.

“The results demonstrate, without question, that the gap between official and actual PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or diesel vehicles,” the expert stated. “Any policy adjustments concerning PHEVs should be made with extreme care and considering this evidence.”