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PHEVs emit nearly five times more global warming emissions than official figures indicate, as per a new report.

Growing Gap In Lab and Real-World CO2 Output

Data reveals that PHEVs release only one-fifth less CO₂ than traditional gas and diesel vehicles, based on analysis conducted by a non-profit organization. That differs significantly with lab tests, which suggested a 75% decrease in pollution.

Researchers studied information from onboard energy use monitors of eight hundred thousand cars sold in the EU from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are decreasing,” stated a lead researcher participating in the report. “That discrepancy is growing and poses a significant problem. Consequently, PHEVs pollute nearly as much as gasoline vehicles.”

Key Factors Driving the Discrepancy

Researchers linked the majority of the gap to inflated estimates of the “electric driving share” – the ratio of kilometers travelled in electric power relative to overall distance. They found that just 27% of travel was completed in EV mode, whereas official assumptions suggested 84%.

Even, when operating in EV mode, emission amounts were well above official estimates. That happened because EV motors were insufficiently powerful enough to function independently, resulting to engines burning fossil fuels for nearly one-third of the travel covered in electric mode.

Regulatory and Financial Consequences

According to calculations, the underestimation of PHEV CO2 output enabled four large carmaker groups to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs could pay approximately €500 more annually in running costs than is estimated under lab conditions.

“The strong statements that automakers often promote about their plug-in hybrid vehicles are obviously far from the truth,” commented a automotive analyst. “Buyers are being misled into thinking that by buying a PHEV, they are helping the environment and cutting money. In reality, PHEVs are only slightly better than regular gas and diesel vehicles in terms of energy use, CO₂ production, and running costs.”

Political Discussion and Automotive Lobbying

Plug-in hybrid cars have lately been drawn back into political discussions as carmakers have pressed the EU to relax CO₂ targets. A planned ban on new combustion engine vehicles in 2035 has faced heavy pressure from the car sector and opposition from EU countries with large automotive manufacturing.

Some high-level politicians have suggested PHEVs as a possible “compromise” option to introduce in the legislation.

One independent energy policy expert, who was not involved with the study, described the report a “very useful addition” after years in which parts of the automotive industry claimed there was insufficient information to properly evaluate actual emissions.

“These findings demonstrate, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ emissions is significantly greater than for petrol or diesel cars,” the expert said. “Any regulatory adjustments regarding PHEVs should be made with utmost caution and considering that data.”