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PHEVs release nearly 5x greater planet-heating pollution than lab-reported data indicate, as per a new report.

Growing Gap Between Lab and Actual Emissions

Statistics shows that PHEVs emit just 19% lower CO₂ than traditional gas and diesel vehicles, based on research conducted by a advocacy organization. That contrasts sharply with laboratory estimates, which assumed a 75% decrease in pollution.

Analysts examined data from onboard fuel consumption monitors 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 greater than lab estimates, increased from three and a half 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 poses a serious problem. Consequently, PHEVs emit nearly as heavily as petrol vehicles.”

Key Factors Driving the Discrepancy

Analysts linked the majority of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers travelled in electric mode relative to total mileage. The team found that only 27% of driving was completed in EV mode, while official assumptions suggested over four-fifths.

Additionally, when running in EV mode, emission levels were well above lab estimates. That occurred because electric motors were not strong enough to function independently, leading to engines burning gasoline for nearly a third of the distance covered in electric mode.

Regulatory and Economic Implications

According to estimates, the lowballing of PHEV emissions enabled four major automaker companies to avoid over €5bn in penalties from 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 extra per year in running expenses than is estimated under lab tests.

“The bold statements that manufacturers often promote about their plug-in hybrid vehicles are clearly far from the mark,” commented a automotive analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little better than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating expenses.”

Policy Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been brought back into political debates as carmakers have pressed the EU to weaken CO₂ standards. A proposed prohibition on sales of new combustion engine cars in 2035 has faced intense lobbying from the automotive sector and opposition from member states with large automotive industries.

Some high-level politicians have suggested plug-in hybrids as a potential “flexibility” option to introduce in the regulation.

One independent energy economics specialist, who was not involved with the research, described the report a “highly valuable contribution” after a long period in which segments of the car sector argued there was too little information to accurately assess actual CO2 output.

“The results demonstrate, beyond any doubt, that the gap between official and actual PHEV energy use and CO₂ output is significantly greater than for gasoline or diesel cars,” the expert said. “Any policy adjustments concerning PHEVs should be implemented with extreme care and considering that evidence.”