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PHEVs emit almost five times greater planet-heating pollution than lab-reported data show, according to a recent analysis.

Growing Discrepancy In Official and Actual CO2 Output

Data reveals that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel vehicles, according to analysis carried out by a non-profit organization. This differs sharply with laboratory estimates, which assumed a three-quarters decrease in pollution.

Analysts studied data from onboard fuel consumption monitors of eight hundred thousand vehicles registered in the EU between 2021 and 2023. They found that actual 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 researcher involved in the study. “This discrepancy is widening and poses a significant problem. Consequently, PHEVs pollute almost as heavily as gasoline vehicles.”

Primary Factors Behind the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the percentage of kilometers driven in electric mode relative to total mileage. The team determined that just 27% of travel was done in EV mode, whereas official assumptions suggested 84%.

Even, when running in electric mode, emission levels were well above lab estimates. That occurred because electric motors were insufficiently powerful sufficient to function independently, resulting to engines burning gasoline for nearly a third of the distance covered in EV mode.

Regulatory and Economic Implications

Based on estimates, the lowballing of PHEV CO2 output enabled four large carmaker groups to avoid over €5bn in fines between 2021 and 2023, by falsely simplifying adherence with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs would spend approximately €500 more per year in operating costs than is estimated under lab tests.

“The bold statements that automakers often promote about their plug-in hybrid cars are clearly way off the mark,” commented a automotive expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and cutting money. Actually, PHEVs are only slightly improved than regular petrol and diesel cars in terms of energy use, CO₂ production, and operating expenses.”

Political Discussion and Automotive Pressure

Plug-in hybrid vehicles have lately been drawn again into policy discussions as carmakers have lobbied the EU to weaken CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced intense lobbying from the automotive industry and resistance from member states with large car manufacturing.

Several senior politicians have proposed PHEVs as a possible “compromise” solution to introduce in the legislation.

One independent energy economics specialist, who was not involved with the research, described the report a “very useful contribution” after years in which segments of the car industry claimed there was too little data to accurately assess actual CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in official and real-world PHEV energy use and CO₂ emissions is much, much larger than for gasoline or diesel vehicles,” the expert said. “Any regulatory adjustments regarding PHEVs should be implemented with extreme care and considering that data.”