🔗 Share this article

Plug-in hybrid cars produce nearly 5x more global warming pollution than lab-reported data show, according to a recent analysis.

Widening Gap In Lab and Actual CO2 Output

Data shows that PHEVs emit just one-fifth less CO₂ than traditional petrol and diesel vehicles, according to analysis carried out by a advocacy group. This contrasts sharply with lab estimates, which suggested a three-quarters decrease in emissions.

Analysts studied information from onboard energy use meters of eight hundred thousand vehicles registered in the EU from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, increased from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported figures are falling,” said a senior analyst involved in the report. “This discrepancy is growing and poses a significant problem. Consequently, PHEVs emit nearly as much as petrol cars.”

Primary Reasons Driving the Emissions Gap

Analysts attributed the majority of the difference to overestimates of the “electric driving share” – the percentage of kilometers driven in electric mode relative to total mileage. The team found that only 27% of travel was done in EV mode, while official assumptions assumed 84%.

Additionally, when running in electric mode, pollution levels were significantly higher than official projections. This happened because EV motors were not strong enough to operate alone, leading to engines using fossil fuels for almost a third of the travel completed in electric mode.

Regulatory and Economic Consequences

According to estimates, the lowballing of PHEV emissions allowed several major carmaker companies to avoid more than €5bn in fines from 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ standards.

Additionally, drivers of PHEVs would spend about €500 extra annually in operating expenses than would be assumed under laboratory tests.

“The strong statements that automakers like to make about their plug-in hybrid vehicles are clearly way off the mark,” stated a transport expert. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the planet and cutting money. In reality, PHEVs are little better than regular petrol and diesel cars in terms of energy consumption, CO₂ emissions, and operating expenses.”

Political Debate and Industry Lobbying

Plug-in hybrid cars have recently been drawn again into political debates as carmakers have lobbied the EU to weaken CO₂ targets. A proposed ban on new internal combustion vehicles in 2035 has faced heavy pressure from the car industry and opposition from member states with significant automotive industries.

Several senior officials have proposed PHEVs as a potential “compromise” option to introduce in the legislation.

One external energy economics expert, who was not involved with the study, described the report a “highly valuable addition” after a long period in which parts of the automotive industry claimed there was too little information to properly evaluate real-world CO2 output.

“These findings show, beyond any doubt, that the gap between lab and real-world PHEV energy use and CO₂ output is much, much larger than for gasoline or diesel cars,” they said. “Any regulatory adjustments regarding PHEVs should be implemented with extreme caution and considering that data.”