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PHEVs emit almost five times more global warming emissions than official figures show, as per a new analysis.

Growing Discrepancy In Official and Actual CO2 Output

Statistics shows that PHEVs emit only 19% less CO₂ than conventional gas and diesel vehicles, based on research carried out by a non-profit organization. That differs sharply with lab tests, which assumed a three-quarters decrease in pollution.

Analysts examined information from onboard energy use monitors of eight hundred thousand cars registered in the EU between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Actual emissions are increasing, while lab-reported emissions are decreasing,” said a lead researcher involved in the study. “This gap is widening and creates a serious issue. As a result, PHEVs pollute nearly as heavily as gasoline vehicles.”

Primary Factors Behind the Discrepancy

Researchers attributed the majority of the gap to inflated estimates of the “electric driving share” – the ratio of kilometers driven in battery power relative to overall distance. They determined that only 27% of travel was completed in electric mode, while official assumptions assumed over four-fifths.

Additionally, when operating in EV mode, pollution amounts were well above official projections. That happened because electric motors were insufficiently powerful sufficient to operate independently, leading to combustion motors using fossil fuels for nearly a third of the distance covered in electric mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV CO2 output allowed four large automaker groups to avoid more than €5bn in fines from 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs would spend about €500 extra annually in operating costs than would be estimated under lab conditions.

“The strong statements that manufacturers like to make about their plug-in hybrid cars are obviously far from the truth,” stated a automotive expert. “Consumers are being misled into believing that by buying a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of energy consumption, CO₂ production, and operating costs.”

Policy Discussion and Industry Pressure

Plug-in hybrid vehicles have recently been brought again into policy discussions as carmakers have pressed the EU to relax CO₂ targets. A proposed ban on new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with significant car industries.

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

One external energy policy specialist, who was not involved with the research, described the analysis a “very useful contribution” after a long period in which parts of the car industry argued there was insufficient data to accurately evaluate real-world emissions.

“The results show, beyond any doubt, that the difference in official and actual PHEV energy use and CO₂ emissions is much, much larger than for gasoline or conventional vehicles,” they said. “Any regulatory adjustments regarding PHEVs should be made with utmost care and in the light of this data.”