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PHEVs emit almost 5x more planet-heating pollution than official figures indicate, as per a new analysis.

Widening Gap Between Lab and Real-World CO2 Output

Data shows that PHEVs release just one-fifth lower CO₂ than conventional petrol and diesel cars, according to research conducted by a advocacy group. This contrasts sharply with lab tests, which suggested a 75% reduction in pollution.

Researchers examined data from onboard energy use monitors of eight hundred thousand cars registered in the EU between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” stated a senior analyst involved in the study. “That discrepancy is widening and poses a significant issue. As a result, PHEVs pollute nearly as much as petrol vehicles.”

Primary Reasons Driving the Emissions Gap

Analysts attributed the majority of the gap to overestimates of the “utility factor” – the percentage of miles driven in electric power compared to overall distance. They found that only 27% of travel was completed in electric mode, while official assumptions suggested 84%.

Even, when running in electric mode, emission levels were significantly higher than lab projections. This occurred because EV motors were not strong enough to function alone, leading to engines using fossil fuels for nearly one-third of the travel covered in EV mode.

Policy and Economic Implications

According to calculations, the underestimation of PHEV emissions allowed four major automaker companies to escape more than €5bn in penalties between 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs would spend approximately €500 more annually in operating costs than would be assumed under lab tests.

“The strong claims that automakers often promote about their PHEV cars are obviously far from the mark,” stated a automotive analyst. “Buyers are being duped into believing that by buying a PHEV, they are helping the environment and saving money. Actually, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating costs.”

Political Discussion and Industry Lobbying

Hybrid cars have lately been brought again into policy discussions as carmakers have pressed the European Union to relax CO₂ standards. A planned ban on new combustion engine vehicles in 2035 has faced heavy pressure from the automotive industry and resistance from EU countries with significant automotive industries.

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

One external energy policy specialist, who was unaffiliated with the study, described the report a “very useful addition” after a long period in which segments of the automotive sector argued there was too little data to properly assess real-world emissions.

“These findings show, without question, that the gap in official and actual PHEV energy use and CO₂ output is significantly larger than for gasoline or conventional vehicles,” the expert stated. “All policy adjustments regarding PHEVs should be made with extreme care and considering that evidence.”