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PHEVs release nearly five times more global warming emissions than lab-reported data show, according to a recent report.

Widening Discrepancy Between Official and Actual CO2 Output

Statistics reveals that PHEVs release just 19% less CO₂ than traditional petrol and diesel vehicles, according to research conducted by a non-profit group. That differs sharply with lab estimates, which assumed a 75% decrease in pollution.

Analysts studied information from onboard energy use meters of eight hundred thousand cars sold in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, up from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are falling,” said a senior analyst participating in the report. “That gap is growing and creates a significant problem. Consequently, PHEVs emit almost as heavily as petrol vehicles.”

Primary Factors Driving the Discrepancy

Analysts attributed most of the gap to inflated estimates of the “electric driving share” – the ratio of miles travelled in battery power relative to overall distance. The team determined that just 27% of travel was done in electric mode, whereas official estimates assumed 84%.

Additionally, when operating in EV mode, pollution levels were significantly higher than official projections. That happened because EV motors were insufficiently powerful enough to operate independently, leading to combustion motors burning gasoline for nearly a third of the travel completed in EV mode.

Regulatory and Financial Implications

According to estimates, the underestimation of PHEV CO2 output allowed several major automaker groups to escape more than €5bn in penalties between 2021 and 2023, by artificially easing compliance with EU average fleet CO₂ standards.

Additionally, owners of PHEVs could pay about €500 extra annually in running costs than is estimated under laboratory tests.

“The bold statements that manufacturers often promote about their PHEV cars are obviously far from the truth,” commented a automotive analyst. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are only slightly improved than regular gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating expenses.”

Political Discussion and Automotive Pressure

Hybrid cars have recently been brought again into political debates as carmakers have lobbied the European Union to weaken CO₂ standards. A planned ban on new combustion engine cars in 2035 has faced heavy pressure from the automotive sector and resistance from member states with significant car industries.

Some high-level officials have suggested plug-in hybrids as a possible “flexibility” option to introduce in the legislation.

One independent energy economics expert, who was unaffiliated with the research, called the analysis a “very useful addition” after years in which parts of the automotive industry argued there was too little information to properly evaluate real-world CO2 output.

“The results show, without question, that the difference between lab and real-world PHEV fuel consumption and CO₂ emissions is much, much greater than for petrol or conventional cars,” they said. “All policy adjustments concerning PHEVs should be made with utmost care and considering that evidence.”