🔗 Share this article

Plug-in hybrid cars produce nearly 5x greater global warming pollution than lab-reported data show, as per a new analysis.

Growing Discrepancy In Official and Real-World CO2 Output

Data reveals that PHEVs emit only 19% lower CO₂ than traditional petrol and diesel vehicles, according to analysis carried out by a advocacy organization. This differs sharply with laboratory tests, which suggested a three-quarters decrease in emissions.

Researchers studied information from onboard energy use monitors of eight hundred thousand vehicles registered in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than official figures, up from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” said a lead analyst participating in the report. “This discrepancy is widening and poses a serious problem. As a result, PHEVs emit nearly as heavily as petrol cars.”

Primary Reasons Driving the Discrepancy

Researchers attributed most of the gap to overestimates of the “electric driving share” – the ratio of miles driven in battery mode relative to total mileage. The team determined that only 27% of driving was completed in EV mode, while lab estimates assumed over four-fifths.

Additionally, when operating in electric mode, emission amounts were significantly higher than official estimates. This occurred because electric motors were not strong enough to function alone, resulting to engines using fossil fuels for nearly a third of the travel covered in electric mode.

Regulatory and Financial Implications

According to calculations, the lowballing of PHEV emissions enabled several major carmaker groups to avoid over €5bn in fines between 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ targets.

Furthermore, drivers of PHEVs would pay approximately €500 more per year in operating costs than is estimated under lab conditions.

“The strong claims that manufacturers often promote about their plug-in hybrid cars are clearly way off the mark,” stated a transport analyst. “Buyers are being duped into thinking that by buying a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are only slightly improved than standard gas and diesel cars in terms of energy consumption, CO₂ production, and operating expenses.”

Policy Discussion and Automotive Lobbying

Hybrid cars have recently been drawn again into political debates as automakers have lobbied the EU to weaken CO₂ standards. A proposed ban on new internal combustion vehicles in 2035 has faced intense pressure from the car industry and resistance from EU countries with large automotive manufacturing.

Some senior politicians have suggested plug-in hybrids as a possible “compromise” option to include in the legislation.

One external energy policy expert, who was not involved with the study, called the analysis a “highly valuable contribution” after years in which parts of the car sector argued there was insufficient data to accurately assess actual emissions.

“These findings show, without question, that the gap between lab and actual PHEV energy use and CO₂ emissions is significantly greater than for gasoline or conventional vehicles,” the expert stated. “Any regulatory changes concerning PHEVs should be implemented with extreme caution and considering this data.”