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PHEVs release almost 5x more planet-heating emissions than official data show, according to a recent analysis.

Widening Gap Between Official and Real-World Emissions

Statistics reveals that PHEVs release just 19% less CO₂ than traditional petrol and diesel cars, based on analysis carried out by a non-profit group. That contrasts sharply with lab tests, which suggested a 75% reduction in pollution.

Researchers examined information from in-vehicle energy use meters of eight hundred thousand cars sold in Europe between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were nearly five times higher than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are falling,” stated a senior analyst involved in the study. “This gap is growing and creates a serious issue. As a result, PHEVs emit nearly as heavily as petrol vehicles.”

Key Reasons Behind the Emissions Gap

Analysts linked most of the gap to overestimates of the “electric driving share” – the ratio of miles travelled in electric mode relative to overall mileage. They determined that only 27% of driving was done in EV mode, while official assumptions assumed over four-fifths.

Additionally, when operating in electric mode, emission amounts were significantly higher than official projections. This happened because EV motors were insufficiently powerful enough to operate alone, leading to combustion motors burning fossil fuels for nearly a third of the travel covered in EV mode.

Regulatory and Economic Implications

According to calculations, the lowballing of PHEV emissions allowed four large carmaker groups to avoid over €5bn in fines from 2021 and 2023, by falsely simplifying compliance with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs would pay about €500 extra per year in running costs than is estimated under laboratory conditions.

“The bold claims that automakers like to make about their plug-in hybrid cars are clearly way off the truth,” commented a automotive expert. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ emissions, and running costs.”

Political Debate and Automotive Pressure

Hybrid cars have lately been drawn again into political discussions as carmakers have pressed the EU to weaken CO₂ standards. A proposed ban on new internal combustion vehicles in 2035 has faced intense pressure from the automotive sector and resistance from member states with significant car manufacturing.

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

An external energy policy specialist, who was not involved with the study, called the report a “very useful addition” after years in which parts of the automotive sector claimed there was too little information to accurately evaluate actual emissions.

“The results demonstrate, beyond any doubt, that the difference between official and actual PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or diesel vehicles,” the expert stated. “All policy adjustments concerning PHEVs should be made with extreme care and in the light of that data.”