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Plug-in hybrid cars emit nearly five times greater planet-heating pollution than official data indicate, as per a new analysis.

Growing Gap Between Official and Real-World Emissions

Data shows that PHEVs release only 19% less CO₂ than traditional petrol and diesel cars, according to research carried out by a non-profit group. This contrasts significantly with laboratory estimates, which assumed a three-quarters decrease in pollution.

Analysts studied information from in-vehicle energy use monitors of eight hundred thousand cars registered in the EU from 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while official figures are decreasing,” stated a lead analyst involved in the study. “This gap is growing and creates a serious problem. As a result, PHEVs emit nearly as heavily as gasoline cars.”

Key Factors Behind the Discrepancy

Researchers linked most of the difference to overestimates of the “electric driving share” – the ratio of miles driven in battery mode compared to overall distance. They found that only a quarter of travel was done in electric mode, while official estimates suggested 84%.

Even, when running in EV mode, pollution levels were significantly higher than official projections. That happened because EV motors were insufficiently powerful enough to operate independently, resulting to combustion motors burning gasoline for nearly one-third of the distance covered in electric mode.

Regulatory and Economic Implications

Based on estimates, the lowballing of PHEV emissions enabled several major carmaker companies to escape over €5bn in penalties between 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ standards.

Additionally, drivers of PHEVs would pay about €500 extra per year in operating costs than is assumed under laboratory conditions.

“The bold claims that automakers often promote about their PHEV vehicles are obviously far from the truth,” stated a automotive expert. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are little better than standard petrol and diesel cars in terms of energy consumption, CO₂ production, and operating costs.”

Political Discussion and Automotive Lobbying

Hybrid cars have recently been brought back into policy discussions as automakers have lobbied the European Union to relax CO₂ standards. A proposed ban on sales of new combustion engine cars in 2035 has faced intense lobbying from the car industry and opposition from EU countries with significant car industries.

Several senior officials have suggested PHEVs as a potential “compromise” option to introduce in the regulation.

One independent energy policy expert, who was unaffiliated with the study, called the report a “very useful contribution” after years in which parts of the automotive industry claimed there was too little data to properly assess actual emissions.

“These findings demonstrate, without question, that the gap in official and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for petrol or conventional cars,” the expert stated. “All policy adjustments concerning PHEVs should be made with extreme care and in the light of this data.”