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Plug-in hybrid cars produce nearly 5x more planet-heating emissions than lab-reported data show, as per a recent analysis.

Growing Discrepancy In Official and Real-World Emissions

Statistics shows that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel vehicles, based on analysis carried out by a advocacy organization. This differs sharply with laboratory estimates, which assumed a 75% reduction in emissions.

Researchers examined data from onboard fuel consumption meters of eight hundred thousand cars sold in the EU from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than official figures, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported figures are decreasing,” stated a senior analyst participating in the study. “This gap is growing and poses a serious problem. As a result, PHEVs emit almost as much as gasoline cars.”

Key Reasons Behind the Emissions Gap

Analysts attributed most of the difference to inflated estimates of the “electric driving share” – the ratio of miles travelled in electric power compared to overall mileage. The team determined that only 27% of travel was done in EV mode, while official estimates assumed 84%.

Additionally, when operating in electric mode, pollution amounts were well above official estimates. That occurred because EV motors were not strong enough to operate independently, resulting to combustion motors burning gasoline for almost a third of the distance covered in EV mode.

Policy and Financial Implications

Based on estimates, the underestimation of PHEV emissions allowed four large carmaker groups to avoid over €5bn in penalties from 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs could pay approximately €500 more annually in operating expenses than would be estimated under laboratory tests.

“The strong claims that manufacturers like to make about their plug-in hybrid vehicles are obviously far from the mark,” commented a automotive expert. “Consumers are being duped into believing that by buying a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are little improved than standard petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and running costs.”

Policy Discussion and Industry Pressure

Hybrid vehicles have lately been drawn again into political discussions as carmakers have lobbied the European Union to weaken CO₂ standards. A proposed ban on sales of new internal combustion cars in 2035 has faced heavy pressure from the automotive industry and resistance from member states with large automotive industries.

Several senior politicians have suggested PHEVs as a potential “flexibility” solution to introduce in the regulation.

An independent energy policy expert, who was not involved with the research, called the analysis a “very useful contribution” after a long period in which parts of the car industry argued there was too little data to accurately evaluate real-world emissions.

“These findings show, without question, that the difference between lab and actual PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel vehicles,” the expert stated. “Any policy changes regarding PHEVs should be implemented with extreme care and in the light of this data.”