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Plug-in hybrid cars release nearly five times more global warming pollution than lab-reported data indicate, as per a recent analysis.

Widening Gap Between Official and Actual Emissions

Data reveals that PHEVs release only 19% lower CO₂ than conventional gas and diesel cars, based on research conducted by a non-profit organization. That contrasts significantly with laboratory tests, which assumed a three-quarters reduction in pollution.

Analysts examined information from onboard energy use meters of eight hundred thousand cars registered in Europe between 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, increased from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are falling,” said a senior analyst participating in the report. “That gap is growing and poses a significant problem. As a result, PHEVs emit almost as much as gasoline vehicles.”

Key Reasons Behind the Discrepancy

Researchers linked the majority of the gap to overestimates of the “electric driving share” – the ratio of miles travelled in battery mode relative to overall mileage. They found that only 27% of travel was completed in electric mode, while lab assumptions suggested over four-fifths.

Even, when operating in EV mode, emission levels were significantly higher than lab projections. That occurred because electric motors were insufficiently powerful sufficient to operate independently, resulting to engines burning fossil fuels for nearly a third of the travel completed in EV mode.

Policy and Financial Consequences

Based on estimates, the lowballing of PHEV CO2 output enabled four major carmaker groups to avoid over €5bn in penalties between 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs could pay approximately €500 more per year in running expenses than would be assumed under lab tests.

“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are clearly far from the truth,” stated a automotive analyst. “Consumers are being duped into thinking that by buying a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of energy consumption, CO₂ production, and operating costs.”

Political Discussion and Automotive Lobbying

Hybrid cars have recently been drawn back into political debates as automakers have pressed the EU to weaken CO₂ targets. A proposed ban on new internal combustion cars in 2035 has faced intense lobbying from the car sector and resistance from EU countries with significant automotive industries.

Some high-level politicians have suggested PHEVs as a possible “flexibility” solution to include in the legislation.

An independent energy policy specialist, who was not involved with the research, described the analysis a “very useful contribution” after years in which segments of the automotive sector claimed there was insufficient data to accurately assess actual emissions.

“The results show, without question, that the difference in official and actual PHEV energy use and CO₂ output is much, much larger than for gasoline or diesel cars,” they said. “All regulatory changes regarding PHEVs should be made with extreme caution and considering that data.”