Plug in Hybrid Vehicles Pollute Nearly as Much as Gasoline Vehicles, Report Reveals

Plug-in hybrid cars emit nearly five times more global warming emissions than official figures indicate, as per a new analysis.

Growing Discrepancy Between Lab and Actual CO2 Output

Statistics reveals that PHEVs release just 19% less CO₂ than traditional gas and diesel cars, based on research carried out by a non-profit organization. That contrasts significantly with laboratory estimates, which assumed a 75% decrease in emissions.

Researchers studied data from in-vehicle fuel consumption meters of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are decreasing,” said a senior researcher involved in the study. “That gap is growing and poses a significant issue. Consequently, PHEVs emit nearly as heavily as gasoline cars.”

Primary Factors Driving the Discrepancy

Researchers linked most of the gap to overestimates of the “electric driving share” – the percentage of miles driven in electric mode relative to overall distance. The team found that just a quarter of travel was done in electric mode, whereas official assumptions suggested 84%.

Additionally, when running in electric mode, pollution amounts were significantly higher than official estimates. That occurred because EV motors were not strong enough to function alone, resulting to engines burning fossil fuels for nearly one-third of the distance covered in electric mode.

Regulatory and Economic Implications

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

Additionally, owners of PHEVs could spend about €500 more per year in operating expenses than would be assumed under laboratory conditions.

“The bold claims that automakers often promote about their plug-in hybrid vehicles are obviously way off the mark,” commented a transport analyst. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the planet and saving money. Actually, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and operating expenses.”

Policy Discussion and Automotive Pressure

Plug-in hybrid cars have recently been brought again into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A proposed prohibition on new combustion engine cars in 2035 has faced intense pressure from the car industry and resistance from EU countries with large automotive industries.

Some high-level officials have suggested PHEVs as a potential “flexibility” option to introduce in the regulation.

One external energy policy expert, who was not involved with the study, described the analysis a “very useful addition” after years in which parts of the automotive industry argued there was insufficient information to properly assess actual emissions.

“The results demonstrate, without question, that the gap between lab and actual PHEV energy use and CO₂ output is much, much greater than for petrol or conventional cars,” the expert stated. “All regulatory adjustments regarding PHEVs should be made with utmost caution and considering this evidence.”