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PHEVs emit nearly 5x more global warming emissions than lab-reported figures indicate, as per a new analysis.

Growing Gap Between Official and Real-World Emissions

Statistics shows that PHEVs release just 19% lower CO₂ than conventional petrol and diesel cars, based on analysis carried out by a advocacy organization. That contrasts sharply with lab tests, which suggested a three-quarters decrease in pollution.

Researchers studied data from onboard energy use meters of eight hundred thousand vehicles registered in Europe between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” stated a lead analyst participating in the report. “This discrepancy is widening and creates a serious issue. Consequently, PHEVs emit almost as much as gasoline vehicles.”

Key Factors Driving the Discrepancy

Researchers attributed the majority of the difference to overestimates of the “electric driving share” – the percentage of kilometers travelled in battery power compared to overall distance. They found that just 27% of travel was completed in electric mode, while official estimates assumed over four-fifths.

Even, when operating in electric mode, emission levels were significantly higher than official projections. That occurred because electric motors were insufficiently powerful sufficient to operate alone, resulting to engines burning gasoline for almost a third of the travel covered in electric mode.

Policy and Economic Implications

Based on calculations, the underestimation of PHEV emissions enabled four major carmaker companies to escape more than €5bn in fines from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs would pay approximately €500 more annually in operating expenses than is assumed under laboratory conditions.

“The strong statements that automakers often promote about their plug-in hybrid cars are obviously way off the truth,” commented a transport expert. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the planet and cutting money. In reality, PHEVs are little better than standard gas and diesel cars in terms of fuel consumption, CO₂ production, and operating expenses.”

Policy Discussion and Industry Pressure

Hybrid vehicles have recently been brought again into policy debates as automakers have lobbied the European Union to relax CO₂ standards. A planned prohibition on new internal combustion cars in 2035 has faced heavy pressure from the automotive industry and opposition from member states with large automotive industries.

Some high-level officials have suggested PHEVs as a possible “flexibility” option to include in the regulation.

An external energy economics specialist, who was not involved with the research, described the report a “very useful addition” after a long period in which parts of the automotive sector argued there was too little data to accurately assess real-world emissions.

“The results show, without question, that the difference in lab and real-world PHEV energy use and CO₂ output is significantly greater than for gasoline or conventional cars,” the expert stated. “Any policy changes regarding PHEVs should be implemented with extreme caution and in the light of that evidence.”