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PHEVs release almost five times greater planet-heating pollution than lab-reported figures indicate, according to a recent analysis.

Growing Discrepancy Between Official and Actual CO2 Output

Data reveals that PHEVs release only 19% lower CO₂ than conventional gas and diesel vehicles, according to analysis conducted by a non-profit organization. This contrasts sharply with lab tests, which assumed a three-quarters decrease in pollution.

Researchers studied data from onboard energy use monitors of eight hundred thousand vehicles registered in the EU between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” stated a lead analyst participating in the report. “That discrepancy is growing and creates a significant issue. As a result, PHEVs emit nearly as much as petrol vehicles.”

Key Reasons Driving the Discrepancy

Analysts linked most of the gap to overestimates of the “electric driving share” – the percentage of kilometers driven in battery power relative to total mileage. The team determined that just 27% of travel was done in EV mode, whereas lab assumptions assumed over four-fifths.

Even, when operating in EV mode, emission levels were significantly higher than lab projections. That occurred because EV motors were insufficiently powerful sufficient to function independently, leading to combustion motors burning gasoline for nearly one-third of the distance completed in EV mode.

Policy and Financial Implications

According to estimates, the underestimation of PHEV emissions allowed several major automaker companies to escape more than €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 extra annually in running costs than would be assumed under lab tests.

“The strong statements that manufacturers often promote about their PHEV cars are clearly way off the truth,” stated a automotive expert. “Consumers are being misled into thinking that by buying a PHEV, they are helping the environment and cutting costs. Actually, PHEVs are little improved than regular petrol and diesel cars in terms of energy consumption, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Lobbying

Hybrid vehicles have recently been brought again into political debates as carmakers have lobbied the European Union to relax CO₂ targets. A proposed prohibition on sales of new internal combustion cars in 2035 has faced intense lobbying from the car industry and resistance from member states with large car industries.

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

One independent energy economics specialist, who was not involved with the research, called the analysis a “very useful contribution” after years in which parts of the car industry argued there was too little information to properly assess real-world CO2 output.

“These findings show, without question, that the gap between official and real-world PHEV energy use and CO₂ output is much, much larger than for petrol or conventional vehicles,” the expert stated. “All regulatory changes regarding PHEVs should be implemented with utmost caution and in the light of that evidence.”