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Plug-in hybrid cars release almost 5x greater planet-heating pollution than official figures show, as per a new report.

Growing Discrepancy In Lab and Actual CO2 Output

Data reveals that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel cars, based on analysis conducted by a advocacy organization. This differs significantly with laboratory estimates, which suggested a 75% reduction in emissions.

Analysts examined information from in-vehicle fuel consumption monitors of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are rising, while official emissions are decreasing,” stated a senior analyst participating in the study. “That discrepancy is widening and creates a significant problem. Consequently, PHEVs emit almost as much as petrol vehicles.”

Key Factors Behind the Discrepancy

Analysts linked most of the difference to overestimates of the “electric driving share” – the percentage of kilometers travelled in electric power relative to total distance. The team determined that only a quarter of driving was done in electric mode, whereas lab estimates suggested 84%.

Additionally, when running in electric mode, emission amounts were significantly higher than lab projections. That happened because EV motors were insufficiently powerful sufficient to function alone, leading to engines using gasoline for almost a third of the distance completed in EV mode.

Regulatory and Economic Consequences

According to calculations, the lowballing of PHEV CO2 output allowed several large automaker companies to avoid more than €5bn in penalties from 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs would spend approximately €500 more per year in running costs than would be assumed under laboratory tests.

“The bold statements that manufacturers often promote about their PHEV cars are obviously way off the mark,” stated a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are only slightly improved than standard petrol and diesel cars in terms of fuel use, CO₂ emissions, and operating costs.”

Political Discussion and Automotive Pressure

Plug-in hybrid vehicles have recently been brought back into political discussions as automakers have pressed the European Union to relax CO₂ targets. A proposed ban on new combustion engine vehicles in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with large automotive manufacturing.

Some high-level politicians have proposed PHEVs as a possible “compromise” solution to introduce in the legislation.

One external energy policy specialist, who was unaffiliated with the research, described the analysis a “highly valuable addition” after a long period in which segments of the automotive sector argued there was insufficient data to properly assess actual CO2 output.

“These findings demonstrate, without question, that the gap between lab and actual PHEV energy use and CO₂ output is significantly greater than for gasoline or diesel vehicles,” the expert said. “Any policy adjustments regarding PHEVs should be made with utmost caution and in the light of that evidence.”