🔗 Share this article

Plug-in hybrid electric vehicles emit almost five times greater global warming emissions than official figures indicate, according to a recent report.

Widening Gap In Lab and Real-World Emissions

Statistics reveals that PHEVs emit only one-fifth less CO₂ than traditional petrol and diesel vehicles, based on analysis carried out by a advocacy organization. That differs significantly with laboratory tests, which assumed a three-quarters decrease in emissions.

Analysts examined information from in-vehicle energy use meters of eight hundred thousand vehicles sold in Europe from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab estimates, up from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” said a lead analyst involved in the study. “That gap is growing and creates a serious issue. Consequently, PHEVs emit almost as much as gasoline vehicles.”

Key Reasons Behind the Emissions Gap

Researchers attributed the majority of the difference to overestimates of the “utility factor” – the ratio of miles driven in electric mode relative to overall mileage. The team determined that just 27% of driving was completed in electric mode, while lab assumptions suggested 84%.

Even, when running in EV mode, emission amounts were significantly higher than lab projections. That happened because EV motors were not strong sufficient to function alone, leading to combustion motors burning gasoline for nearly a third of the distance covered in EV mode.

Policy and Economic Consequences

Based on estimates, the lowballing of PHEV emissions allowed several large carmaker groups to avoid over €5bn in fines from 2021 and 2023, by falsely simplifying adherence with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs would spend about €500 more per year in operating costs than would be estimated under laboratory conditions.

“The bold statements that automakers often promote about their plug-in hybrid cars are obviously far from the mark,” commented a transport expert. “Buyers are being misled into believing that by purchasing a PHEV, they are helping the planet and cutting money. Actually, PHEVs are little improved than standard gas and diesel cars in terms of fuel use, CO₂ production, and running expenses.”

Political Discussion and Automotive Lobbying

Plug-in hybrid cars have recently been brought again into political discussions as carmakers have pressed the European Union to relax CO₂ targets. A proposed prohibition on new combustion engine cars in 2035 has faced intense pressure from the automotive sector and opposition from EU countries with large automotive manufacturing.

Some high-level politicians have suggested plug-in hybrids as a potential “flexibility” option to introduce in the regulation.

An independent energy economics expert, who was not involved with the study, called the analysis a “very useful addition” after a long period in which parts of the car industry argued there was too little information to properly evaluate real-world CO2 output.

“The results demonstrate, without question, that the gap in official and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or conventional vehicles,” the expert said. “Any policy changes regarding PHEVs should be implemented with extreme caution and in the light of this data.”