🔗 Share this article

Plug-in hybrid electric vehicles release nearly five times greater global warming emissions than lab-reported figures indicate, as per a recent analysis.

Widening Discrepancy Between Official and Actual Emissions

Data shows that PHEVs emit just one-fifth lower CO₂ than traditional petrol and diesel cars, based on research carried out by a advocacy organization. That differs sharply with laboratory tests, which suggested a three-quarters reduction in pollution.

Analysts examined data from in-vehicle energy use meters of eight hundred thousand cars sold in the EU between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, up from 3.5 times in 2021.

“Actual emissions are increasing, while official figures are decreasing,” said a lead researcher participating in the study. “This discrepancy is growing and creates a serious problem. Consequently, PHEVs pollute nearly as heavily as petrol cars.”

Key Factors Behind the Emissions Gap

Researchers linked most of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers driven in electric power relative to total distance. The team determined that just a quarter of travel was done in electric mode, while official estimates suggested over four-fifths.

Even, when running in EV mode, pollution amounts were significantly higher than lab projections. That occurred because electric motors were not strong sufficient to operate independently, resulting to engines using fossil fuels for nearly one-third of the distance completed in electric mode.

Policy and Economic Implications

According to calculations, the underestimation of PHEV CO2 output allowed four major automaker groups to avoid over €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs could spend about €500 extra per year in operating expenses than is estimated under lab tests.

“The strong statements that manufacturers often promote about their PHEV vehicles are clearly way off the truth,” commented a automotive expert. “Buyers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are only slightly better than standard petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating expenses.”

Political Discussion and Industry Pressure

Plug-in hybrid cars have recently been brought again into political debates as carmakers have pressed the EU to weaken CO₂ targets. A proposed ban on new internal combustion cars in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with significant car industries.

Several senior officials have suggested PHEVs as a possible “compromise” solution to introduce in the regulation.

One independent energy economics expert, who was not involved with the study, described the analysis a “very useful contribution” after years in which parts of the automotive sector argued there was insufficient data to properly assess real-world CO2 output.

“The results demonstrate, without question, that the gap between official and actual PHEV energy use and CO₂ emissions is much, much larger than for petrol or diesel cars,” the expert said. “Any policy changes regarding PHEVs should be implemented with utmost care and considering that evidence.”