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PHEVs emit nearly five times more planet-heating pollution than official figures indicate, as per a recent analysis.

Growing Gap Between Official and Real-World CO2 Output

Statistics shows that PHEVs release just one-fifth less CO₂ than traditional gas and diesel vehicles, according to research conducted by a advocacy group. This differs sharply with lab estimates, which suggested a three-quarters reduction in emissions.

Analysts examined data from in-vehicle fuel consumption monitors of 800,000 vehicles sold in Europe from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, up from three and a half times in 2021.

“Actual emissions are increasing, while lab-reported emissions are decreasing,” stated a senior researcher participating in the study. “This discrepancy is growing and poses a significant issue. Consequently, PHEVs emit nearly as heavily as petrol vehicles.”

Primary Factors Driving the Discrepancy

Researchers attributed the majority of the gap to overestimates of the “utility factor” – the percentage of miles travelled in battery mode compared to total mileage. The team found that just a quarter of driving was done in EV mode, while official estimates suggested 84%.

Even, when running in electric mode, pollution amounts were significantly higher than official estimates. That happened because EV motors were insufficiently powerful enough to operate alone, resulting to engines using gasoline for almost one-third of the travel covered in EV mode.

Policy and Financial Consequences

According to calculations, the underestimation of PHEV emissions allowed 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.

Additionally, owners of PHEVs would pay approximately €500 more per year in operating expenses than would be estimated under laboratory tests.

“The bold statements that automakers often promote about their PHEV vehicles are clearly way off the mark,” stated a automotive analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are only slightly better than regular petrol and diesel cars in terms of energy consumption, CO₂ emissions, and operating expenses.”

Political Discussion and Automotive Pressure

Plug-in hybrid cars have lately been drawn back into policy debates as automakers have lobbied the European Union to weaken CO₂ targets. A planned prohibition on new internal combustion vehicles in 2035 has faced intense pressure from the car sector and resistance from EU countries with significant automotive industries.

Some high-level officials have suggested plug-in hybrids as a potential “compromise” option to include in the legislation.

An independent energy policy specialist, who was not involved with the research, called the report a “very useful addition” after years in which segments of the automotive sector argued there was too little information to properly evaluate actual emissions.

“The results show, beyond any doubt, that the difference in official and actual PHEV energy use and CO₂ emissions is significantly greater than for petrol or diesel cars,” they stated. “All regulatory adjustments concerning PHEVs should be implemented with extreme caution and in the light of that data.”