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Plug-in hybrid cars produce nearly 5x greater global warming emissions than lab-reported data show, as per a recent analysis.

Widening Gap In Official and Actual CO2 Output

Data shows that PHEVs release only 19% less CO₂ than conventional gas and diesel vehicles, according to analysis conducted by a non-profit organization. That contrasts significantly with laboratory tests, which suggested a three-quarters reduction in emissions.

Analysts examined data from in-vehicle energy use meters of eight hundred thousand vehicles sold in Europe between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are falling,” stated a lead researcher involved in the study. “That gap is growing and creates a serious issue. As a result, PHEVs pollute nearly as heavily as petrol cars.”

Primary Factors Behind the Discrepancy

Researchers linked most of the gap to overestimates of the “utility factor” – the ratio of miles travelled in electric mode compared to overall mileage. They determined that only a quarter of driving was done in electric mode, whereas official estimates suggested over four-fifths.

Even, when operating in electric mode, emission levels were well above lab projections. That occurred because EV motors were insufficiently powerful sufficient to function independently, resulting to combustion motors using fossil fuels for nearly a third of the distance completed in electric mode.

Policy and Economic Consequences

According to calculations, the underestimation of PHEV emissions allowed several large carmaker groups to avoid more than €5bn in fines between 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs could pay about €500 extra annually in running expenses than is estimated under lab conditions.

“The bold statements that automakers often promote about their plug-in hybrid vehicles are obviously far from the mark,” commented a transport analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are only slightly better than standard gas and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been drawn back into policy discussions as automakers have pressed the European Union to weaken CO₂ targets. A proposed ban on new combustion engine vehicles in 2035 has faced heavy lobbying from the car industry and opposition from member states with large automotive industries.

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

An external energy policy expert, who was unaffiliated with the research, described the report a “highly valuable addition” after a long period in which parts of the car industry argued there was insufficient information to properly assess actual emissions.

“The results show, without question, that the gap between official and actual PHEV energy use and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” they said. “Any policy changes regarding PHEVs should be implemented with utmost care and considering that data.”