🔗 Share this article

PHEVs produce almost 5x greater planet-heating emissions than lab-reported data show, as per a new report.

Growing Gap Between Official and Real-World CO2 Output

Statistics shows that PHEVs emit only one-fifth lower CO₂ than conventional gas and diesel cars, according to research conducted by a non-profit organization. That contrasts sharply with laboratory estimates, which assumed a 75% decrease in pollution.

Researchers studied information from in-vehicle energy use meters of 800,000 vehicles registered in Europe from 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported figures are falling,” stated a lead researcher participating in the report. “This discrepancy is growing and poses a serious issue. As a result, PHEVs pollute almost as heavily as gasoline vehicles.”

Key Reasons Behind the Discrepancy

Researchers linked the majority of the gap to overestimates of the “electric driving share” – the ratio of kilometers driven in battery mode compared to total mileage. The team determined that just 27% of driving was completed in EV mode, while official estimates assumed over four-fifths.

Additionally, when operating in electric mode, pollution levels were well above official projections. That occurred because electric motors were not strong sufficient to operate independently, leading to engines burning fossil fuels for nearly one-third of the travel covered in electric mode.

Regulatory and Financial Implications

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

Additionally, owners of PHEVs could spend approximately €500 extra annually in operating expenses than is estimated under lab conditions.

“The bold statements that manufacturers like to make about their PHEV vehicles are obviously way off the truth,” stated a transport expert. “Buyers are being duped into believing that by purchasing a PHEV, they are helping the environment and saving money. Actually, PHEVs are little improved than standard petrol and diesel cars in terms of fuel consumption, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been brought again into political discussions as automakers have lobbied the European Union to relax CO₂ standards. A proposed prohibition on new combustion engine cars in 2035 has faced heavy pressure from the automotive industry and resistance from member states with significant car manufacturing.

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

One independent energy economics specialist, who was not involved with the research, called the analysis a “very useful addition” after a long period in which segments of the car sector claimed there was too little information to accurately assess real-world CO2 output.

“The results demonstrate, beyond any doubt, that the gap between official and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or conventional vehicles,” the expert said. “All policy adjustments concerning PHEVs should be made with extreme caution and considering this evidence.”