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Plug-in hybrid cars produce almost five times greater global warming emissions than official figures indicate, as per a recent report.

Growing Gap Between Lab and Real-World CO2 Output

Statistics shows that PHEVs emit only one-fifth less CO₂ than traditional petrol and diesel vehicles, according to research carried out by a advocacy organization. This differs sharply with laboratory tests, which suggested a three-quarters reduction in pollution.

Analysts studied information from onboard energy use meters of eight hundred thousand cars registered in Europe from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are decreasing,” said a senior analyst involved in the report. “This discrepancy is growing and poses a significant problem. Consequently, PHEVs emit almost as much as gasoline vehicles.”

Key Factors Behind the Emissions Gap

Analysts linked the majority of the gap to inflated estimates of the “electric driving share” – the ratio of miles travelled in battery power compared to total distance. They found that only a quarter of travel was done in EV mode, whereas lab estimates suggested over four-fifths.

Even, when running in EV mode, emission levels were significantly higher than lab projections. This occurred because electric motors were insufficiently powerful enough to operate independently, leading to combustion motors using fossil fuels for almost a third of the travel completed in electric mode.

Policy and Financial Consequences

Based on estimates, the lowballing of PHEV CO2 output allowed four major automaker companies to escape over €5bn in fines from 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ standards.

Additionally, owners of PHEVs would pay approximately €500 extra annually in running costs than would be assumed under lab tests.

“The strong statements that automakers like to make about their plug-in hybrid cars are obviously far from the mark,” commented a automotive analyst. “Buyers are being duped into believing that by purchasing a PHEV, they are helping the planet and saving money. Actually, PHEVs are little improved than standard gas and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Hybrid cars have lately been brought back into political debates as automakers have pressed the EU to relax CO₂ targets. A planned prohibition on new combustion engine vehicles in 2035 has faced intense lobbying from the car sector and opposition from EU countries with large car manufacturing.

Several high-level politicians have suggested plug-in hybrids as a possible “flexibility” option to include in the regulation.

One external energy policy specialist, who was not involved with the study, called the analysis a “very useful contribution” after a long period in which segments of the car sector claimed there was insufficient data to properly assess real-world emissions.

“The results show, beyond any doubt, that the gap in official and real-world PHEV fuel consumption and CO₂ output is much, much larger than for petrol or conventional vehicles,” the expert said. “Any policy changes concerning PHEVs should be implemented with extreme caution and in the light of this evidence.”