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PHEVs produce nearly five times more global warming pollution than official figures indicate, according to a recent report.

Widening Discrepancy Between Lab and Actual Emissions

Statistics reveals that PHEVs emit just one-fifth less CO₂ than traditional petrol and diesel cars, based on analysis carried out by a advocacy group. This contrasts sharply with laboratory tests, which assumed a three-quarters decrease in pollution.

Analysts examined information from onboard fuel consumption meters of 800,000 vehicles sold in Europe between 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.

“Real-world CO2 output are rising, while official emissions are decreasing,” said a senior researcher participating in the report. “That gap is growing and poses a significant problem. As a result, PHEVs pollute nearly as much as gasoline vehicles.”

Primary Reasons Driving the Emissions Gap

Researchers attributed most of the gap to overestimates of the “electric driving share” – the ratio of miles travelled in electric mode relative to total distance. The team found that just a quarter of driving was completed in EV mode, while lab assumptions assumed over four-fifths.

Even, when running in EV mode, pollution levels were significantly higher than official estimates. This occurred because EV motors were insufficiently powerful sufficient to function independently, leading to engines using gasoline for nearly one-third of the distance covered in EV mode.

Regulatory and Economic Consequences

Based on calculations, the underestimation of PHEV CO2 output allowed four major automaker companies to avoid over €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs could spend about €500 more per year in operating costs than is estimated under lab conditions.

“The strong claims that automakers like to make about their plug-in hybrid vehicles are obviously way off the truth,” commented a automotive analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the planet and saving money. In reality, PHEVs are only slightly improved than regular gas and diesel cars in terms of energy consumption, CO₂ emissions, and running expenses.”

Political Discussion and Automotive Pressure

Hybrid cars have recently been drawn back into political discussions as carmakers have pressed the EU to weaken CO₂ targets. A proposed prohibition on sales of new combustion engine vehicles in 2035 has faced intense lobbying from the automotive sector and opposition from EU countries with large car industries.

Several high-level politicians have suggested PHEVs as a potential “flexibility” solution to include in the regulation.

One external energy policy specialist, who was not involved with the research, called the report a “highly valuable addition” after years in which segments of the automotive industry argued there was too little data to properly assess actual CO2 output.

“The results demonstrate, without question, that the difference in lab and actual PHEV energy use and CO₂ emissions is significantly larger than for petrol or conventional vehicles,” the expert said. “All regulatory adjustments concerning PHEVs should be implemented with utmost care and in the light of this data.”