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Plug-in hybrid cars release nearly 5x more planet-heating pollution than official data show, as per a recent report.

Growing Discrepancy In Lab and Actual CO2 Output

Data reveals that PHEVs release only one-fifth less CO₂ than traditional gas and diesel cars, based on research carried out by a advocacy organization. This differs sharply with lab tests, which suggested a 75% reduction in emissions.

Researchers studied information from onboard energy use 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 lab estimates, increased from 3.5 times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are decreasing,” said a senior analyst participating in the report. “That discrepancy is growing and poses a serious problem. Consequently, PHEVs pollute almost as heavily as gasoline cars.”

Primary Reasons Driving the Emissions Gap

Researchers linked the majority of the gap to overestimates of the “utility factor” – the percentage of miles travelled in battery power relative to overall distance. They found that only 27% of travel was completed in EV mode, whereas official estimates assumed over four-fifths.

Even, when operating in EV mode, emission amounts were well above lab projections. This happened because electric motors were not strong sufficient to function independently, leading to combustion motors burning gasoline for nearly one-third of the distance covered in electric mode.

Regulatory and Economic Consequences

According to calculations, the underestimation of PHEV emissions enabled several large carmaker groups to escape over €5bn in fines between 2021 and 2023, by artificially simplifying adherence with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could spend about €500 more annually in running costs than would be assumed under lab tests.

“The strong statements that automakers often promote about their PHEV vehicles are obviously far from the mark,” commented a transport analyst. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are only slightly better than standard gas and diesel cars in terms of energy use, CO₂ production, and running expenses.”

Political Discussion and Automotive Pressure

Hybrid cars have recently been drawn back into policy discussions as automakers have lobbied the EU to relax CO₂ standards. A proposed ban on new combustion engine cars in 2035 has faced intense lobbying from the automotive industry and resistance from member states with significant automotive industries.

Some high-level officials have proposed PHEVs as a possible “compromise” option to include in the legislation.

An external energy policy specialist, who was unaffiliated with the study, described the analysis a “very useful contribution” after a long period in which segments of the automotive industry claimed there was insufficient information to properly evaluate actual CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in official and real-world PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or conventional vehicles,” the expert stated. “All policy changes regarding PHEVs should be made with extreme caution and in the light of that evidence.”