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Plug-in hybrid cars release nearly five times more planet-heating pollution than official figures show, as per a new analysis.

Widening Gap In Official and Actual Emissions

Statistics reveals that PHEVs release just one-fifth less CO₂ than conventional gas and diesel cars, according to research carried out by a non-profit organization. This differs sharply with lab tests, which assumed a 75% reduction in emissions.

Analysts studied information from in-vehicle energy use monitors of eight hundred thousand vehicles registered in the EU between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Actual emissions are increasing, while official figures are decreasing,” stated a lead analyst participating in the study. “That gap is growing and poses a serious issue. Consequently, PHEVs pollute nearly as heavily as gasoline vehicles.”

Key Reasons Driving the Emissions Gap

Researchers attributed most of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in electric power compared to total mileage. They found that only a quarter of driving was done in electric mode, whereas lab estimates suggested over four-fifths.

Even, when operating in EV mode, pollution levels were well above lab projections. This occurred because electric motors were not strong sufficient to function alone, resulting to combustion motors using fossil fuels for nearly a third of the distance covered in electric mode.

Policy and Economic Consequences

According to calculations, the lowballing of PHEV CO2 output allowed several large automaker groups to escape over €5bn in fines between 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ targets.

Additionally, owners of PHEVs could spend about €500 extra per year in operating expenses than would be estimated under lab conditions.

“The bold statements that automakers often promote about their PHEV vehicles are clearly way off the mark,” stated a transport expert. “Consumers are being misled into thinking that by buying a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are only slightly improved than standard gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and running expenses.”

Political Debate and Automotive Lobbying

Plug-in hybrid cars have recently been brought back into policy debates as automakers have lobbied the EU to relax CO₂ targets. A planned ban on sales of new combustion engine vehicles in 2035 has faced heavy lobbying from the automotive sector and opposition from member states with significant automotive manufacturing.

Some senior politicians have suggested PHEVs as a possible “compromise” option to include in the regulation.

One independent energy policy expert, who was unaffiliated with the research, called the report a “very useful contribution” after a long period in which segments of the automotive sector argued there was too little data to accurately assess actual emissions.

“The results demonstrate, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or diesel vehicles,” they said. “Any regulatory adjustments concerning PHEVs should be made with utmost caution and considering that evidence.”