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PHEVs emit almost 5x more global warming emissions than lab-reported data show, according to a recent report.

Widening Gap In Official and Actual Emissions

Data shows that PHEVs emit just one-fifth lower CO₂ than traditional petrol and diesel vehicles, based on analysis carried out by a non-profit group. This differs sharply with laboratory tests, which suggested a 75% reduction in pollution.

Researchers examined data from onboard fuel consumption meters of eight hundred thousand cars sold in Europe between 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” said a senior researcher participating in the study. “This discrepancy is growing and creates a serious problem. As a result, PHEVs pollute almost as much as gasoline vehicles.”

Key Reasons Behind the Discrepancy

Researchers linked the majority of the gap to inflated estimates of the “utility factor” – the percentage of miles travelled in electric mode relative to overall mileage. They found that just 27% of travel was done in EV mode, while lab estimates assumed 84%.

Even, when running in electric mode, pollution amounts were well above lab projections. This occurred because EV motors were not strong sufficient to operate independently, resulting to engines using gasoline for almost one-third of the travel covered in electric mode.

Regulatory and Financial Implications

According to calculations, the lowballing of PHEV emissions enabled several major carmaker companies to avoid more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs would pay approximately €500 more per year in operating costs than would be estimated under lab tests.

“The bold claims that automakers often promote about their PHEV cars are clearly way off the mark,” commented a automotive expert. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the planet and cutting money. In reality, PHEVs are only slightly improved than standard petrol and diesel cars in terms of energy use, CO₂ production, and running costs.”

Policy Debate and Industry Pressure

Hybrid cars have recently been drawn back into policy debates as automakers have lobbied the EU to weaken CO₂ targets. A proposed ban on sales of new internal combustion vehicles in 2035 has faced intense lobbying from the automotive sector and resistance from member states with large car industries.

Some high-level politicians have proposed PHEVs as a possible “compromise” solution to include in the regulation.

One independent energy policy expert, who was not involved with the research, called the report a “highly valuable contribution” after years in which parts of the car industry argued there was too little information to properly assess real-world emissions.

“These findings demonstrate, beyond any doubt, that the gap in lab and real-world PHEV energy use and CO₂ output is significantly greater than for gasoline or diesel cars,” the expert stated. “Any regulatory adjustments regarding PHEVs should be made with extreme caution and considering this evidence.”