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PHEVs emit nearly 5x more planet-heating pollution than lab-reported figures show, as per a recent analysis.

Growing Discrepancy In Official and Actual CO2 Output

Statistics reveals that PHEVs release just 19% lower CO₂ than conventional petrol and diesel cars, based on analysis carried out by a advocacy organization. That contrasts sharply with lab tests, which suggested a 75% decrease in emissions.

Researchers studied data from in-vehicle energy use meters of 800,000 vehicles registered in the EU between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are decreasing,” said a senior researcher participating in the report. “This gap is growing and creates a significant issue. As a result, PHEVs emit almost as much as gasoline cars.”

Key Reasons Driving the Discrepancy

Researchers linked the majority of the gap to inflated estimates of the “electric driving share” – the ratio of miles travelled in electric power relative to total distance. The team determined that just 27% of driving was done in electric mode, whereas official estimates assumed over four-fifths.

Additionally, when operating in electric mode, pollution levels were significantly higher than official projections. That occurred because EV motors were not strong enough to operate alone, leading to combustion motors burning gasoline for almost one-third of the travel covered in EV mode.

Policy and Economic Consequences

Based on estimates, the lowballing of PHEV emissions enabled four major carmaker companies to avoid over €5bn in fines from 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs would spend approximately €500 more per year in operating costs than is estimated under laboratory conditions.

“The bold claims that manufacturers often promote about their plug-in hybrid cars are clearly far from the truth,” commented a transport expert. “Buyers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and cutting money. In reality, PHEVs are little better than regular gas and diesel cars in terms of energy use, CO₂ emissions, and running costs.”

Policy Debate and Automotive Lobbying

Hybrid vehicles have recently been brought again into political discussions as automakers have pressed the European Union to relax CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced heavy pressure from the car sector and resistance from member states with significant car manufacturing.

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

One independent energy policy expert, who was not involved with the research, described the report a “highly valuable contribution” after years in which segments of the car industry claimed there was too little information to properly evaluate actual emissions.

“The results show, without question, that the difference between lab and actual PHEV energy use and CO₂ emissions is much, much greater than for gasoline or diesel vehicles,” the expert said. “Any regulatory changes regarding PHEVs should be made with extreme caution and considering that evidence.”