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Plug-in hybrid cars emit almost five times more planet-heating emissions than official data indicate, as per a recent report.

Growing Discrepancy In Lab and Actual Emissions

Data shows that PHEVs release only one-fifth lower CO₂ than traditional gas and diesel vehicles, according to analysis conducted by a advocacy group. This differs significantly with laboratory estimates, which suggested a 75% reduction in pollution.

Researchers examined information from in-vehicle energy use monitors of eight hundred thousand vehicles registered in the EU from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, up from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are decreasing,” stated a lead researcher involved in the report. “This discrepancy is widening and poses a significant problem. As a result, PHEVs emit nearly as heavily as petrol cars.”

Primary Reasons Driving the Discrepancy

Researchers attributed the majority of the difference to overestimates of the “electric driving share” – the percentage of miles driven in battery power compared to overall distance. They determined that just 27% of travel was done in electric mode, while official estimates assumed over four-fifths.

Even, when running in EV mode, emission amounts were well above lab estimates. This happened because electric motors were insufficiently powerful sufficient to function alone, leading to combustion motors burning gasoline for nearly a third of the distance covered in electric mode.

Regulatory and Economic Consequences

Based on estimates, the lowballing of PHEV CO2 output enabled several large automaker companies to avoid more than €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could pay about €500 more annually in operating costs than would be assumed under lab conditions.

“The strong claims that manufacturers often promote about their plug-in hybrid cars are clearly far from the truth,” stated a transport analyst. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are little better than regular gas and diesel cars in terms of fuel use, CO₂ production, and running expenses.”

Policy Debate and Automotive Pressure

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

Several high-level politicians have proposed PHEVs as a possible “compromise” solution to introduce in the regulation.

One external energy policy expert, who was unaffiliated with the study, called the analysis a “very useful contribution” after a long period in which parts of the automotive industry argued there was too little information to accurately assess real-world CO2 output.

“The results demonstrate, without question, that the gap in lab and actual PHEV energy use and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” the expert stated. “Any policy adjustments regarding PHEVs should be made with utmost care and considering this data.”