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Plug-in hybrid electric vehicles emit almost 5x greater planet-heating pollution than lab-reported data show, as per a recent report.

Widening Gap In Lab and Actual CO2 Output

Statistics shows that PHEVs release just one-fifth lower CO₂ than traditional petrol and diesel cars, according to analysis conducted by a non-profit organization. This contrasts sharply with lab tests, which assumed a three-quarters decrease in pollution.

Analysts studied information from onboard energy use meters of 800,000 vehicles registered in Europe between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab estimates, up from 3.5 times in 2021.

“Real-world CO2 output are rising, while lab-reported emissions are falling,” stated a lead analyst participating in the study. “This discrepancy is growing and creates a serious issue. Consequently, PHEVs pollute almost as heavily as gasoline cars.”

Key Reasons Driving the Discrepancy

Researchers attributed the majority of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in electric mode relative to overall mileage. They determined that only a quarter of travel was done in electric mode, whereas lab estimates assumed 84%.

Even, when operating in EV mode, emission amounts were well above official projections. This happened because EV motors were not strong sufficient to operate alone, resulting to engines using gasoline for nearly a third of the travel covered in EV mode.

Policy and Economic Implications

According to estimates, the lowballing of PHEV emissions enabled four major carmaker groups to avoid over €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs would spend approximately €500 extra annually in running costs than is estimated under laboratory conditions.

“The strong claims that automakers often promote about their PHEV cars are clearly far from the mark,” stated a automotive analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are benefiting the planet and saving money. Actually, PHEVs are little improved than regular gas and diesel cars in terms of fuel use, CO₂ production, and running expenses.”

Policy Debate and Automotive Lobbying

Hybrid cars have recently been brought back into political debates as carmakers have pressed the EU to weaken CO₂ standards. A planned prohibition on sales of new combustion engine vehicles in 2035 has faced intense pressure from the car sector and resistance from member states with large car industries.

Some senior officials have suggested PHEVs as a possible “compromise” option to introduce in the legislation.

One independent energy policy specialist, who was not involved with the study, described the report a “very useful addition” after a long period in which segments of the car sector claimed there was too little data to accurately assess actual emissions.

“These findings demonstrate, beyond any doubt, that the difference between lab and actual PHEV energy use and CO₂ emissions is significantly greater than for gasoline or conventional vehicles,” the expert stated. “Any policy changes concerning PHEVs should be implemented with extreme caution and considering that evidence.”