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Plug-in hybrid cars produce almost five times more global warming pollution than lab-reported data show, as per a recent analysis.

Widening Discrepancy Between Lab and Real-World Emissions

Data shows that PHEVs release only 19% less CO₂ than traditional petrol and diesel vehicles, according to analysis conducted by a non-profit organization. This differs significantly with laboratory tests, which suggested a 75% decrease in emissions.

Researchers studied information from onboard fuel consumption meters of eight hundred thousand vehicles sold in Europe between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” stated a lead analyst involved in the study. “This gap is growing and poses a significant issue. Consequently, PHEVs pollute almost as heavily as petrol cars.”

Key Factors Behind the Discrepancy

Analysts linked most of the gap to inflated estimates of the “electric driving share” – the ratio of miles travelled in electric power compared to overall distance. They found that only a quarter of travel was done in electric mode, whereas official assumptions suggested 84%.

Even, when operating in electric mode, pollution amounts were well above lab projections. This occurred because electric motors were insufficiently powerful enough to operate independently, resulting to combustion motors burning fossil fuels for nearly a third of the distance completed in electric mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV emissions enabled several major carmaker companies to avoid over €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ targets.

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

“The strong statements that manufacturers like to make about their plug-in hybrid cars are obviously way off the truth,” stated a automotive analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the environment and saving costs. Actually, PHEVs are little improved than regular gas and diesel vehicles in terms of fuel consumption, CO₂ production, and running costs.”

Political Discussion and Automotive Pressure

Hybrid vehicles have lately been drawn again into political discussions as automakers have lobbied the EU to weaken CO₂ targets. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense pressure from the car sector and opposition from EU countries with large car manufacturing.

Some high-level politicians have suggested plug-in hybrids as a possible “compromise” solution to include in the regulation.

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

“The results show, without question, that the difference between lab and actual PHEV energy use and CO₂ emissions is significantly greater than for gasoline or diesel vehicles,” they said. “All policy adjustments concerning PHEVs should be made with extreme care and in the light of this data.”