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PHEVs emit nearly five times greater planet-heating pollution than lab-reported data indicate, according to a recent analysis.

Widening Gap Between Lab and Real-World Emissions

Statistics reveals that PHEVs emit just 19% less CO₂ than conventional petrol and diesel cars, according to analysis conducted by a non-profit organization. This differs sharply with laboratory tests, which assumed a 75% decrease in pollution.

Analysts studied information from in-vehicle fuel consumption meters of eight hundred thousand vehicles sold in the EU from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, up from three and a half times in 2021.

“Actual emissions are rising, while lab-reported figures are falling,” said a lead researcher involved in the report. “This gap is widening and creates a significant problem. As a result, PHEVs pollute nearly as much as petrol cars.”

Primary Reasons Behind the Discrepancy

Researchers linked the majority of the gap to overestimates of the “utility factor” – the percentage of kilometers travelled in electric mode relative to total mileage. They found that just 27% of travel was completed in EV mode, whereas lab estimates assumed 84%.

Even, when running in electric mode, emission amounts were well above lab estimates. That occurred because EV motors were insufficiently powerful sufficient to operate independently, leading to combustion motors using gasoline for almost a third of the travel covered in electric mode.

Regulatory and Economic Implications

According to estimates, the lowballing of PHEV emissions enabled several major carmaker groups to escape over €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs could spend about €500 extra per year in running costs than would be assumed under lab conditions.

“The bold claims that manufacturers like to make about their PHEV vehicles are obviously way off the truth,” commented a transport expert. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running expenses.”

Political Discussion and Automotive Lobbying

Hybrid cars have recently been drawn again into policy discussions as carmakers have lobbied the European Union to weaken CO₂ standards. A planned prohibition on new combustion engine vehicles in 2035 has faced intense lobbying from the car sector and resistance from EU countries with significant car industries.

Some senior officials have proposed plug-in hybrids as a possible “compromise” solution to include in the legislation.

One external energy economics specialist, who was unaffiliated with the study, called the analysis a “very useful contribution” after years in which segments of the car sector argued there was too little data to properly assess actual emissions.

“The results demonstrate, without question, that the difference between official and real-world PHEV fuel consumption and CO₂ output is much, much larger than for petrol or conventional cars,” the expert said. “Any policy adjustments concerning PHEVs should be made with utmost care and considering this evidence.”