Plug in Hybrid Cars Pollute Nearly as Heavily as Petrol Vehicles, Study Reveals

Plug-in hybrid cars release nearly five times more planet-heating emissions than lab-reported data indicate, as per a recent report.

Widening Gap Between Lab and Real-World Emissions

Statistics reveals that PHEVs release just one-fifth lower CO₂ than conventional petrol and diesel vehicles, according to research conducted by a non-profit organization. That differs significantly with lab estimates, which assumed a 75% decrease in emissions.

Researchers examined data from onboard energy use monitors of eight hundred thousand cars sold in Europe between 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official emissions are falling,” said a lead researcher involved in the report. “That discrepancy is widening and creates a serious problem. As a result, PHEVs emit nearly as heavily as gasoline cars.”

Key Reasons Driving the Discrepancy

Analysts attributed the majority of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers travelled in battery mode relative to total distance. The team determined that only a quarter of travel was done in EV mode, while lab assumptions suggested over four-fifths.

Even, when running in electric mode, emission levels were well above lab projections. That happened because EV motors were insufficiently powerful enough to operate independently, leading to engines using gasoline for almost one-third of the distance covered in electric mode.

Regulatory and Financial Consequences

According to calculations, the lowballing of PHEV CO2 output allowed several major automaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could pay approximately €500 more annually in running expenses than would be estimated under lab conditions.

“The strong claims that automakers often promote about their PHEV vehicles are clearly way off the truth,” commented a automotive analyst. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and saving costs. In reality, PHEVs are little better than regular petrol and diesel cars in terms of energy use, CO₂ production, and operating costs.”

Political Debate and Industry Pressure

Plug-in hybrid cars have recently been drawn back into policy debates as carmakers have pressed the EU to relax CO₂ standards. A planned prohibition on new combustion engine vehicles in 2035 has faced intense lobbying from the automotive sector and resistance from EU countries with large car manufacturing.

Some high-level officials have proposed PHEVs as a potential “compromise” option to introduce in the regulation.

An external energy economics expert, who was not involved with the study, described the analysis a “very useful addition” after a long period in which segments of the car sector argued there was too little data to properly assess real-world emissions.

“These findings demonstrate, without question, that the gap in official and actual PHEV energy use and CO₂ emissions is significantly greater than for petrol or conventional cars,” they stated. “All policy changes regarding PHEVs should be implemented with utmost care and considering that evidence.”