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PHEVs produce nearly 5x greater planet-heating emissions than lab-reported data indicate, as per a recent report.

Growing Gap Between Official and Real-World CO2 Output

Statistics shows that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel vehicles, according to research carried out by a non-profit organization. That differs sharply with laboratory tests, which assumed a three-quarters reduction in emissions.

Researchers examined information from in-vehicle fuel consumption meters of 800,000 vehicles sold in Europe between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while official emissions are decreasing,” said a lead analyst involved in the study. “That discrepancy is growing and creates a significant issue. As a result, PHEVs pollute almost as much as petrol cars.”

Key Reasons Driving the Emissions Gap

Analysts linked most of the gap to overestimates of the “utility factor” – the ratio of kilometers driven in electric power relative to total distance. The team determined that only a quarter of travel was done in EV mode, while official assumptions assumed 84%.

Even, when operating in electric mode, pollution levels were significantly higher than official estimates. That happened because EV motors were insufficiently powerful enough to operate independently, resulting to engines using gasoline for nearly a third of the travel covered in electric mode.

Policy and Economic Implications

According to calculations, the lowballing of PHEV emissions allowed four major automaker groups to escape more than €5bn in penalties between 2021 and 2023, by artificially easing compliance with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs could spend about €500 extra annually in operating expenses than is estimated under lab tests.

“The bold claims that automakers like to make about their PHEV cars are obviously way off the mark,” commented a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are helping the environment and saving money. Actually, PHEVs are little improved than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and running expenses.”

Policy Discussion and Automotive Pressure

Plug-in hybrid cars have recently been brought back into political discussions as carmakers have pressed the EU to weaken CO₂ standards. A planned ban on new combustion engine cars in 2035 has faced intense lobbying from the car industry and opposition from member states with significant automotive manufacturing.

Some senior politicians have proposed PHEVs as a possible “flexibility” solution to include in the regulation.

One external energy policy expert, who was not involved with the study, described the analysis a “very useful addition” after a long period in which segments of the automotive industry claimed there was too little information to properly evaluate real-world emissions.

“These findings demonstrate, without question, that the gap between lab and actual PHEV energy use and CO₂ output is significantly greater than for petrol or diesel vehicles,” the expert said. “All regulatory adjustments concerning PHEVs should be implemented with utmost care and considering that evidence.”