🔗 Share this article

Plug-in hybrid electric vehicles release nearly 5x greater global warming emissions than lab-reported data show, as per a new report.

Widening Gap In Lab and Actual Emissions

Data reveals that PHEVs release only 19% lower CO₂ than conventional petrol and diesel cars, based on analysis conducted by a advocacy group. This contrasts significantly with lab estimates, which assumed a three-quarters decrease in emissions.

Analysts examined information from in-vehicle energy use monitors of eight hundred thousand cars sold in the EU from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official estimates, up from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are decreasing,” said a senior analyst participating in the study. “This discrepancy is widening and poses a serious issue. Consequently, PHEVs emit almost as much as gasoline cars.”

Primary Factors Behind the Emissions Gap

Analysts linked most of the difference to overestimates of the “utility factor” – the ratio of miles driven in electric mode compared to overall mileage. The team determined that only a quarter of travel was completed in electric mode, while lab estimates suggested 84%.

Additionally, when running in EV mode, emission amounts were well above official estimates. That occurred because electric motors were not strong enough to function alone, resulting to combustion motors using gasoline for almost one-third of the travel completed in EV mode.

Policy and Economic Implications

Based on estimates, the underestimation of PHEV CO2 output allowed four large automaker groups to avoid over €5bn in penalties from 2021 and 2023, by falsely simplifying adherence with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs would spend approximately €500 more annually in operating expenses than would be estimated under lab tests.

“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are clearly way off the mark,” commented a automotive analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are only slightly better than regular gas and diesel cars in terms of energy use, CO₂ production, and operating expenses.”

Policy Discussion and Automotive Pressure

Hybrid cars have recently been brought again into policy debates as automakers have lobbied the EU to relax CO₂ standards. A proposed prohibition on new combustion engine vehicles in 2035 has faced heavy lobbying from the car sector and resistance from member states with large automotive industries.

Several senior officials have proposed plug-in hybrids as a potential “compromise” option to introduce in the regulation.

One external energy policy expert, who was not involved with the study, described the analysis a “very useful addition” after a long period in which parts of the automotive industry argued there was too little information to properly evaluate real-world CO2 output.

“These findings show, beyond any doubt, that the difference between official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or diesel vehicles,” they stated. “All policy changes regarding PHEVs should be implemented with extreme care and considering that data.”