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PHEVs emit nearly 5x greater global warming pollution than lab-reported figures indicate, according to a recent report.

Widening Gap Between Official and Real-World CO2 Output

Data reveals that PHEVs release just 19% lower CO₂ than traditional gas and diesel vehicles, according to research conducted by a advocacy organization. This contrasts significantly with laboratory estimates, which suggested a 75% reduction in emissions.

Analysts studied data from onboard fuel consumption meters of eight hundred thousand cars sold in the EU between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official figures, up from three and a half times in 2021.

“Real-world CO2 output are rising, while official figures are falling,” stated a senior researcher involved in the study. “That gap is growing and creates a significant issue. Consequently, PHEVs pollute almost as much as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Analysts linked the majority of the difference to inflated estimates of the “electric driving share” – the percentage of miles driven in electric mode compared to total distance. The team determined that just a quarter of travel was completed in electric mode, whereas official estimates suggested over four-fifths.

Additionally, when running in EV mode, pollution levels were well above official projections. That occurred because electric motors were insufficiently powerful sufficient to function alone, leading to combustion motors burning gasoline for almost a third of the distance completed in EV mode.

Regulatory and Economic Consequences

Based on estimates, the underestimation of PHEV CO2 output allowed several large automaker companies to escape more than €5bn in fines from 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could pay approximately €500 extra annually in operating expenses than would be estimated under laboratory conditions.

“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are obviously way off the mark,” commented a automotive analyst. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little better than regular petrol and diesel cars in terms of energy consumption, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid cars have recently been drawn back into policy discussions as carmakers have pressed the EU to weaken CO₂ targets. A proposed prohibition on new combustion engine cars in 2035 has faced heavy lobbying from the automotive sector and opposition from EU countries with large car industries.

Several high-level officials have proposed PHEVs as a potential “compromise” solution to include in the legislation.

One external energy economics specialist, who was not involved with the research, described the report a “very useful contribution” after a long period in which parts of the automotive sector claimed there was insufficient information to properly assess actual CO2 output.

“The results demonstrate, beyond any doubt, that the difference between lab and real-world PHEV fuel consumption and CO₂ emissions is significantly greater than for petrol or diesel cars,” the expert stated. “All regulatory adjustments concerning PHEVs should be made with utmost care and in the light of this data.”