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PHEVs release nearly five times more planet-heating pollution than lab-reported figures indicate, as per a new analysis.

Growing Discrepancy In Lab and Real-World Emissions

Data shows that PHEVs release just one-fifth less CO₂ than conventional gas and diesel vehicles, according to analysis conducted by a non-profit organization. That differs sharply with laboratory estimates, which suggested a three-quarters decrease in pollution.

Researchers examined data from onboard fuel consumption monitors of 800,000 cars sold in the EU from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, increased from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported figures are falling,” said a lead researcher participating in the study. “This discrepancy is widening and creates a significant issue. Consequently, PHEVs pollute almost as heavily as petrol vehicles.”

Primary Factors Behind the Discrepancy

Analysts linked the majority of the difference to inflated estimates of the “utility factor” – the ratio of kilometers driven in electric power relative to total distance. The team determined that just a quarter of travel was completed in EV mode, whereas official assumptions suggested 84%.

Even, when operating in electric mode, emission amounts were well above lab estimates. This occurred because EV motors were insufficiently powerful sufficient to operate independently, resulting to engines burning gasoline for almost a third of the travel covered in electric mode.

Policy and Economic Consequences

Based on estimates, the underestimation of PHEV emissions enabled four large carmaker groups to escape more than €5bn in fines from 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ targets.

Furthermore, owners of PHEVs could pay approximately €500 extra per year in operating expenses than would be estimated under laboratory tests.

“The strong statements that automakers often promote about their PHEV vehicles are clearly far from the mark,” stated a automotive analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are only slightly better than standard petrol and diesel cars in terms of energy consumption, CO₂ emissions, and operating costs.”

Policy Discussion and Industry Pressure

Hybrid vehicles have lately been brought back into political discussions as automakers have pressed the European Union to relax CO₂ standards. A proposed prohibition on sales of new combustion engine cars in 2035 has faced intense pressure from the automotive industry and opposition from member states with significant automotive manufacturing.

Some senior politicians have suggested PHEVs as a potential “flexibility” option to include in the regulation.

An independent energy policy expert, who was unaffiliated with the study, described the analysis a “very useful addition” after years in which parts of the car sector claimed there was insufficient data to accurately evaluate real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the difference between lab and actual PHEV fuel consumption and CO₂ emissions is significantly larger than for gasoline or diesel cars,” the expert stated. “Any policy changes concerning PHEVs should be made with utmost care and considering this evidence.”