Plug in Hybrid electric Cars Pollute Nearly as Heavily as Gasoline Cars, Study Finds

PHEVs emit almost five times greater planet-heating pollution than official data indicate, according to a recent report.

Widening Discrepancy Between Official and Actual Emissions

Data shows that PHEVs emit only 19% lower CO₂ than traditional gas and diesel vehicles, based on analysis carried out by a advocacy organization. That contrasts significantly with laboratory tests, which assumed a three-quarters decrease in emissions.

Analysts examined information from in-vehicle fuel consumption meters of 800,000 vehicles sold in Europe from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, up from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported figures are decreasing,” said a lead analyst involved in the study. “That discrepancy is widening and creates a serious problem. Consequently, PHEVs pollute nearly as heavily as petrol vehicles.”

Key Reasons Behind the Discrepancy

Analysts linked most of the difference to overestimates of the “utility factor” – the percentage of kilometers driven in battery mode relative to overall distance. The team found that only 27% of travel was completed in EV mode, while lab estimates assumed 84%.

Even, when running in electric mode, emission levels were well above lab projections. This occurred because electric motors were insufficiently powerful sufficient to function alone, leading to engines burning fossil fuels for nearly one-third of the distance covered in electric mode.

Policy and Economic Implications

Based on calculations, the underestimation of PHEV emissions enabled several major automaker companies to avoid over €5bn in fines from 2021 and 2023, by falsely simplifying adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs could spend approximately €500 more per year in running costs than would be estimated under laboratory tests.

“The strong claims that automakers like to make about their plug-in hybrid cars are obviously far from the truth,” commented a automotive expert. “Buyers are being duped into believing that by buying a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of energy use, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Hybrid vehicles have lately been drawn back into political debates as carmakers have pressed the European Union to weaken CO₂ standards. A proposed ban on new combustion engine cars in 2035 has faced heavy lobbying from the car sector and resistance from member states with significant automotive manufacturing.

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

An independent energy policy expert, who was not involved with the study, called the report a “highly valuable contribution” after a long period in which segments of the car industry argued there was insufficient information to properly evaluate real-world CO2 output.

“The results demonstrate, beyond any doubt, that the difference in official and actual PHEV energy use and CO₂ emissions is much, much larger than for petrol or diesel vehicles,” they stated. “Any policy adjustments concerning PHEVs should be made with utmost caution and in the light of that data.”