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Plug-in hybrid cars emit almost five times more global warming emissions than official figures indicate, according to a recent report.

Widening Gap In Lab and Actual CO2 Output

Statistics shows that PHEVs release only one-fifth less CO₂ than conventional gas and diesel vehicles, based on research conducted by a advocacy organization. This contrasts significantly with laboratory tests, which suggested a 75% decrease in emissions.

Analysts studied information from onboard fuel consumption monitors of eight hundred thousand vehicles sold in the EU between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, increased from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported figures are decreasing,” said a lead researcher participating in the study. “That discrepancy is widening and poses a serious issue. As a result, PHEVs emit nearly as heavily as petrol vehicles.”

Key Reasons Driving the Discrepancy

Analysts attributed the majority of the gap to inflated estimates of the “electric driving share” – the percentage of kilometers travelled in electric power relative to overall mileage. The team determined that only 27% of driving was done in EV mode, whereas official estimates assumed over four-fifths.

Even, when operating in EV mode, emission amounts were significantly higher than official projections. That happened because electric motors were insufficiently powerful enough to function alone, leading to engines burning gasoline for nearly one-third of the distance completed in electric mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV CO2 output allowed several major carmaker companies to avoid more than €5bn in fines between 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs would pay approximately €500 extra per year in operating expenses than is estimated under laboratory tests.

“The strong claims that manufacturers like to make about their PHEV vehicles are obviously far from the mark,” commented a automotive analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are only slightly better than regular gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and running expenses.”

Political Debate and Industry Lobbying

Hybrid cars have recently been drawn back into policy discussions as carmakers have lobbied the EU to weaken CO₂ targets. A proposed ban on new combustion engine vehicles in 2035 has faced heavy pressure from the car industry and opposition from EU countries with large automotive industries.

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

An external energy policy specialist, who was not involved with the research, described the report a “very useful contribution” after a long period in which parts of the automotive industry argued there was too little data to accurately assess real-world emissions.

“The results show, beyond any doubt, that the difference in official and real-world PHEV energy use and CO₂ output is much, much larger than for petrol or conventional vehicles,” they stated. “All regulatory changes regarding PHEVs should be implemented with extreme care and in the light of this data.”