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Plug-in hybrid electric vehicles produce nearly five times more planet-heating pollution than lab-reported figures indicate, as per a new report.

Growing Gap In Official and Actual CO2 Output

Statistics reveals that PHEVs release just 19% less CO₂ than conventional petrol and diesel vehicles, based on research carried out by a advocacy organization. That contrasts significantly with lab estimates, which suggested a three-quarters reduction in pollution.

Researchers examined information from onboard energy use monitors of eight hundred thousand vehicles registered in Europe between 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are rising, while official figures are decreasing,” said a senior analyst participating in the study. “This discrepancy is widening and creates a serious problem. Consequently, PHEVs pollute nearly as much as petrol vehicles.”

Primary Factors Behind the Emissions Gap

Analysts attributed most of the difference to inflated estimates of the “utility factor” – the percentage of kilometers driven in battery power relative to total distance. They determined that just a quarter of travel was done in electric mode, whereas official estimates assumed over four-fifths.

Even, when running in EV mode, pollution amounts were well above lab estimates. This happened because EV motors were not strong sufficient to operate independently, resulting to engines using gasoline for nearly one-third of the distance covered in EV mode.

Policy and Financial Implications

According to estimates, the lowballing of PHEV CO2 output allowed several major automaker companies to avoid more than €5bn in fines from 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs would pay approximately €500 extra per year in operating costs than is estimated under lab conditions.

“The strong statements that automakers often promote about their PHEV cars are clearly far from the mark,” commented a transport analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are benefiting the planet and cutting money. In reality, PHEVs are only slightly better than regular petrol and diesel cars in terms of fuel use, CO₂ emissions, and running expenses.”

Political Discussion and Automotive Pressure

Hybrid cars have lately been brought back into political debates as carmakers have lobbied the EU to weaken CO₂ standards. A proposed prohibition on new internal combustion vehicles in 2035 has faced heavy pressure from the car sector and resistance from EU countries with large automotive industries.

Several high-level politicians have suggested plug-in hybrids as a possible “flexibility” option to include in the regulation.

One independent energy policy expert, who was unaffiliated with the study, described the analysis a “highly valuable addition” after a long period in which segments of the automotive industry argued there was insufficient data to properly evaluate real-world CO2 output.

“The results demonstrate, without question, that the gap between lab and actual PHEV energy use and CO₂ emissions is much, much larger than for petrol or diesel cars,” the expert said. “Any policy adjustments concerning PHEVs should be implemented with extreme care and considering that data.”