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PHEVs produce nearly five times more planet-heating pollution than lab-reported data indicate, as per a new analysis.

Growing Gap In Lab and Actual Emissions

Statistics reveals that PHEVs emit just 19% lower CO₂ than conventional gas and diesel vehicles, based on research conducted by a non-profit organization. That differs significantly with lab tests, which assumed a three-quarters decrease in emissions.

Analysts examined data from onboard fuel consumption monitors of eight hundred thousand cars sold 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 lab estimates, up from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported figures are decreasing,” said a lead researcher participating in the report. “That gap is growing and creates a serious problem. Consequently, PHEVs pollute almost as much as gasoline cars.”

Primary Factors Driving the Discrepancy

Analysts linked the majority of the difference to overestimates of the “electric driving share” – the ratio of miles driven in electric power compared to total mileage. The team found that just 27% of driving was completed in electric mode, whereas lab assumptions assumed over four-fifths.

Even, when operating in electric mode, emission amounts were significantly higher than official estimates. This happened because EV motors were insufficiently powerful sufficient to operate independently, leading to combustion motors burning fossil fuels for almost a third of the travel covered in EV mode.

Policy and Economic Implications

According to calculations, the underestimation of PHEV emissions enabled several major automaker companies to avoid more than €5bn in fines from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs could pay approximately €500 more annually in running costs than is estimated under laboratory conditions.

“The bold claims that manufacturers often promote about their PHEV vehicles are clearly far from the mark,” commented a transport expert. “Buyers are being duped into believing that by purchasing a PHEV, they are helping the planet and saving costs. In reality, PHEVs are only slightly better than regular gas and diesel cars in terms of fuel use, CO₂ production, and running expenses.”

Political Discussion and Automotive Pressure

Hybrid cars have recently been brought again into political debates as carmakers have lobbied the European Union to relax CO₂ targets. A proposed ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car sector and resistance from EU countries with large car industries.

Some senior politicians have suggested PHEVs as a possible “compromise” solution to include in the legislation.

An independent energy policy specialist, who was unaffiliated with the research, described the report a “very useful contribution” after years in which segments of the car industry claimed there was too little data to properly assess actual emissions.

“These findings demonstrate, without question, that the difference in lab and real-world PHEV energy use and CO₂ output is much, much greater than for petrol or conventional vehicles,” they stated. “Any regulatory adjustments concerning PHEVs should be made with utmost caution and considering this data.”