🔗 Share this article

Plug-in hybrid electric vehicles produce almost five times greater planet-heating emissions than official figures indicate, as per a new analysis.

Growing Discrepancy Between Lab and Real-World CO2 Output

Statistics shows that PHEVs release just one-fifth lower CO₂ than conventional gas and diesel cars, according to analysis carried out by a advocacy group. That differs sharply with laboratory estimates, which assumed a three-quarters decrease in emissions.

Analysts studied data from onboard fuel consumption monitors of eight hundred thousand vehicles sold in the EU between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported figures are decreasing,” said a lead researcher involved in the study. “That gap is growing and poses a serious issue. As a result, PHEVs emit nearly as heavily as gasoline cars.”

Primary Reasons Behind the Emissions Gap

Analysts linked 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 determined that just a quarter of travel was done in EV mode, whereas official estimates assumed over four-fifths.

Even, when operating in electric mode, emission levels were significantly higher than official projections. This occurred because electric motors were insufficiently powerful enough to operate independently, resulting to combustion motors burning fossil fuels for nearly one-third of the distance covered in electric mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV CO2 output enabled several major automaker groups to avoid more than €5bn in fines between 2021 and 2023, by falsely simplifying adherence with European Union fleet-average CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 extra annually in running costs than is assumed under laboratory conditions.

“The bold claims that manufacturers like to make about their plug-in hybrid cars are obviously far from the mark,” commented a transport analyst. “Consumers are being misled into believing that by purchasing a PHEV, they are helping the environment and saving money. In reality, PHEVs are only slightly better than regular petrol and diesel cars in terms of energy use, CO₂ emissions, and running costs.”

Political Discussion and Industry Lobbying

Plug-in hybrid cars have lately been brought again into political discussions as automakers have pressed the EU to weaken CO₂ targets. A planned prohibition on sales of new internal combustion 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 proposed plug-in hybrids as a potential “compromise” option to include in the legislation.

One independent energy economics specialist, who was unaffiliated with the study, called the report a “highly valuable addition” after a long period in which parts of the car industry argued there was too little information to properly evaluate real-world emissions.

“These findings demonstrate, without question, that the difference in lab and actual PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or conventional cars,” the expert said. “Any regulatory changes regarding PHEVs should be made with extreme caution and in the light of this evidence.”