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

Widening Gap Between Official and Real-World CO2 Output

Data reveals that PHEVs emit just one-fifth less CO₂ than conventional gas and diesel vehicles, according to analysis carried out by a advocacy organization. That differs significantly with lab tests, which assumed a 75% decrease in pollution.

Researchers studied data from in-vehicle energy use monitors of eight hundred thousand vehicles registered in Europe between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than official estimates, increased from 3.5 times in 2021.

“Actual emissions are increasing, while official emissions are decreasing,” stated a senior analyst involved in the report. “This gap is widening and poses a significant problem. As a result, PHEVs emit nearly as much as gasoline cars.”

Key Reasons Behind the Discrepancy

Analysts attributed most of the gap to overestimates of the “utility factor” – the ratio of miles driven in electric mode compared to total distance. The team determined that only 27% of travel was completed in electric mode, while lab estimates assumed 84%.

Even, when operating in EV mode, pollution levels were significantly higher than lab estimates. That occurred because EV motors were not strong sufficient to operate alone, resulting to engines using fossil fuels for almost a third of the distance completed in electric mode.

Regulatory and Financial Consequences

Based on estimates, the lowballing of PHEV CO2 output enabled several major automaker companies to avoid over €5bn in fines between 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ targets.

Additionally, owners of PHEVs would pay approximately €500 extra annually in running costs than is estimated under lab tests.

“The strong claims that manufacturers like to make about their PHEV cars are obviously far from the truth,” stated a transport expert. “Consumers are being duped into believing that by buying a PHEV, they are helping the environment and cutting costs. Actually, PHEVs are only slightly better than standard petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and running expenses.”

Political Debate and Automotive Lobbying

Plug-in hybrid cars have recently been brought again into policy discussions as automakers have lobbied the EU to weaken CO₂ targets. A proposed ban on new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with large automotive industries.

Several senior politicians have suggested PHEVs as a potential “compromise” solution to include in the regulation.

An external energy policy specialist, who was not involved with the research, called the analysis a “highly valuable addition” after years in which parts of the automotive sector argued there was too little information to accurately assess actual CO2 output.

“These findings show, beyond any doubt, that the difference in official and real-world PHEV energy use and CO₂ emissions is significantly greater than for petrol or conventional cars,” they stated. “Any policy adjustments regarding PHEVs should be made with utmost care and considering this evidence.”