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Plug-in hybrid cars emit nearly 5x greater global warming pollution than official data show, as per a recent report.

Widening Discrepancy In Lab and Real-World Emissions

Statistics shows that PHEVs emit just 19% lower CO₂ than traditional petrol and diesel cars, according to analysis carried out by a advocacy organization. This contrasts sharply with laboratory tests, which suggested a three-quarters reduction in pollution.

Researchers examined data from onboard energy use meters of 800,000 cars registered in Europe from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, up from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” stated a lead analyst involved in the report. “This discrepancy is growing and poses a significant problem. As a result, PHEVs pollute nearly as much as gasoline cars.”

Key Factors Behind the Emissions Gap

Researchers linked most of the difference to overestimates of the “electric driving share” – the percentage of miles travelled in battery power relative to total distance. They found that just a quarter of travel was completed in electric mode, while lab estimates assumed over four-fifths.

Additionally, when running in electric mode, pollution levels were well above lab estimates. This occurred because EV motors were insufficiently powerful enough to operate alone, leading to combustion motors using gasoline for almost a third of the distance covered in EV mode.

Regulatory and Economic Implications

According to calculations, the underestimation of PHEV emissions enabled several major carmaker companies to avoid more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 more annually in operating expenses than is assumed under lab conditions.

“The strong claims that manufacturers like to make about their PHEV vehicles are clearly way off the truth,” stated a transport expert. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the planet and saving money. In reality, PHEVs are only slightly improved than regular gas and diesel vehicles in terms of energy use, CO₂ emissions, and running costs.”

Political Debate and Industry Pressure

Hybrid cars have recently been drawn again into policy discussions as carmakers have lobbied the European Union to weaken CO₂ standards. A planned ban on new combustion engine cars in 2035 has faced intense pressure from the automotive sector and resistance from EU countries with large car manufacturing.

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

One independent energy economics specialist, who was unaffiliated with the study, described the analysis a “very useful addition” after years in which segments of the automotive sector argued there was too little information to accurately assess real-world emissions.

“The results demonstrate, beyond any doubt, that the difference in official and actual PHEV energy use and CO₂ emissions is much, much greater than for gasoline or diesel cars,” they stated. “All regulatory changes concerning PHEVs should be made with extreme care and considering this data.”