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PHEVs emit nearly five times more global warming pollution than lab-reported data indicate, according to a recent report.

Widening Gap In Official and Actual Emissions

Data reveals that PHEVs emit just 19% lower CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a non-profit organization. That differs sharply with laboratory tests, which suggested a 75% reduction in pollution.

Researchers studied data from onboard energy use monitors of 800,000 vehicles sold in Europe between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Actual emissions are rising, while official figures are decreasing,” stated a senior analyst participating in the study. “This discrepancy is widening and poses a significant problem. As a result, PHEVs emit almost as heavily as gasoline vehicles.”

Key Reasons Behind the Discrepancy

Analysts linked most of the difference to overestimates of the “utility factor” – the ratio of kilometers driven in electric power relative to overall mileage. The team found that only 27% of travel was done in EV mode, whereas official estimates suggested 84%.

Even, when operating in EV mode, emission levels were well above lab projections. That happened because EV motors were insufficiently powerful sufficient to operate independently, leading to combustion motors using gasoline for almost one-third of the travel completed in EV mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV emissions allowed four major carmaker groups to escape over €5bn in penalties between 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ standards.

Furthermore, drivers of PHEVs would spend about €500 extra annually in running costs than is estimated under laboratory tests.

“The bold statements that automakers often promote about their PHEV cars are obviously way off the truth,” commented a transport expert. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the environment and cutting costs. Actually, PHEVs are only slightly improved than standard petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Pressure

Hybrid cars have recently been brought back into policy discussions as carmakers have pressed the EU to weaken CO₂ targets. A proposed ban on new combustion engine cars in 2035 has faced intense pressure from the car industry and opposition from member states with large automotive industries.

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

An 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 sector claimed there was too little data to properly assess real-world emissions.

“The results show, beyond any doubt, that the difference in official and actual PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel cars,” the expert said. “Any regulatory adjustments concerning PHEVs should be made with utmost caution and considering this data.”