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Plug-in hybrid cars release almost 5x more global warming emissions than official data show, as per a recent analysis.

Growing Gap In Lab and Actual CO2 Output

Statistics reveals that PHEVs emit only 19% less CO₂ than traditional petrol and diesel cars, based on research carried out by a advocacy group. This differs significantly with lab tests, which assumed a three-quarters decrease in emissions.

Analysts examined data from in-vehicle energy use meters of 800,000 cars sold in Europe between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official estimates, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while official figures are decreasing,” said a senior analyst participating in the study. “This discrepancy is growing and poses a serious issue. Consequently, PHEVs pollute almost as heavily as petrol vehicles.”

Primary Reasons Behind the Discrepancy

Analysts attributed the majority of the difference to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric mode compared to overall mileage. They found that only 27% of driving was done in EV mode, while lab assumptions assumed over four-fifths.

Even, when running in EV mode, pollution amounts were well above official estimates. This occurred because EV motors were not strong sufficient to function alone, leading to engines using gasoline for almost one-third of the distance completed in electric mode.

Policy and Financial Consequences

According to estimates, the underestimation of PHEV emissions enabled four large automaker companies to escape over €5bn in fines from 2021 and 2023, by falsely simplifying adherence with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs could pay approximately €500 extra per year in operating costs than is assumed under lab tests.

“The strong claims that automakers like to make about their PHEV vehicles are clearly way off the truth,” stated a automotive expert. “Consumers are being duped into believing that by purchasing a PHEV, they are helping the planet and cutting money. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of energy consumption, CO₂ production, and running costs.”

Policy Debate and Industry Lobbying

Hybrid vehicles have recently been brought again into political discussions as carmakers have lobbied the European Union to relax CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced heavy lobbying from the car industry and resistance from member states with large automotive manufacturing.

Some high-level officials have suggested PHEVs as a possible “compromise” solution to include in the regulation.

One external energy economics specialist, who was not involved with the study, described the analysis a “highly valuable contribution” after years in which segments of the car industry argued there was insufficient data to accurately assess real-world emissions.

“The results demonstrate, beyond any doubt, that the gap between official and actual PHEV energy use and CO₂ emissions is much, much greater than for petrol or conventional vehicles,” the expert said. “All policy changes regarding PHEVs should be implemented with utmost caution and considering this evidence.”