🔗 Share this article

PHEVs release nearly five times more planet-heating emissions than lab-reported data show, according to a new analysis.

Widening Discrepancy In Lab and Actual CO2 Output

Statistics reveals that PHEVs release only 19% lower CO₂ than conventional petrol and diesel vehicles, based on analysis conducted by a non-profit organization. That differs significantly with lab tests, which assumed a 75% reduction in emissions.

Researchers examined data from in-vehicle fuel consumption monitors of eight hundred thousand vehicles sold in Europe between 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported figures are falling,” said a senior analyst participating in the study. “This discrepancy is growing and creates a significant issue. As a result, PHEVs pollute almost as heavily as petrol vehicles.”

Key Factors Behind the Discrepancy

Researchers attributed most of the difference to overestimates of the “utility factor” – the ratio of miles travelled in battery power relative to overall distance. They found that just a quarter of travel was done in EV mode, whereas lab assumptions assumed 84%.

Even, when running in EV mode, pollution amounts were well above official projections. That happened because EV motors were not strong sufficient to operate alone, resulting to engines using gasoline for almost one-third of the travel covered in EV mode.

Regulatory and Economic Consequences

According to estimates, the lowballing of PHEV emissions allowed several large automaker groups to escape over €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs would pay approximately €500 more per year in running expenses than is estimated under laboratory tests.

“The strong statements that manufacturers often promote about their PHEV vehicles are clearly far from the mark,” commented a transport expert. “Consumers are being duped into believing that by purchasing a PHEV, they are helping the planet and cutting money. In reality, PHEVs are only slightly improved than standard petrol and diesel cars in terms of fuel use, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Hybrid vehicles have recently been brought back into policy debates as carmakers have pressed the EU to weaken CO₂ targets. A planned ban on new combustion engine cars in 2035 has faced heavy pressure from the automotive sector and opposition from member states with large automotive manufacturing.

Some senior politicians have suggested plug-in hybrids as a potential “compromise” option to introduce in the regulation.

An independent energy policy expert, who was not involved with the research, called the analysis a “highly valuable addition” after years in which parts of the car industry argued there was too little data to accurately assess real-world CO2 output.

“These findings show, without question, that the gap in official and real-world PHEV fuel consumption and CO₂ emissions is significantly larger than for petrol or diesel vehicles,” the expert stated. “Any policy changes regarding PHEVs should be implemented with utmost caution and considering this evidence.”