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PHEVs release almost 5x more global warming pollution than lab-reported figures show, according to a recent analysis.

Growing Discrepancy In Official and Real-World CO2 Output

Data reveals that PHEVs release only one-fifth lower CO₂ than conventional gas and diesel cars, according to research carried out by a advocacy group. This differs significantly with laboratory estimates, which assumed a three-quarters reduction in pollution.

Analysts examined data from onboard fuel consumption meters of eight hundred thousand cars registered in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than lab estimates, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” stated a lead analyst participating in the report. “This discrepancy is widening and creates a serious issue. Consequently, PHEVs emit nearly as heavily as gasoline cars.”

Key Reasons Behind the Emissions Gap

Analysts attributed the majority of the gap to overestimates of the “electric driving share” – the percentage of kilometers travelled in battery mode relative to total distance. The team determined that only a quarter of travel was done in EV mode, whereas official estimates suggested 84%.

Additionally, when running in EV mode, emission levels were well above official estimates. This occurred because EV motors were not strong enough to function independently, leading to engines burning fossil fuels for nearly a third of the distance covered in EV mode.

Policy and Financial Implications

Based on calculations, the underestimation of PHEV emissions enabled several large automaker groups to escape more than €5bn in fines from 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ standards.

Additionally, drivers of PHEVs could pay approximately €500 extra per year in operating expenses than would be assumed under lab tests.

“The strong claims that automakers like to make about their plug-in hybrid cars are obviously way off the truth,” stated a transport analyst. “Consumers are being misled into believing that by purchasing a PHEV, they are helping the planet and saving money. Actually, PHEVs are little better than standard petrol and diesel cars in terms of fuel use, CO₂ emissions, and running expenses.”

Political Debate and Automotive Lobbying

Plug-in hybrid vehicles have lately been brought back into policy discussions as carmakers have pressed the European Union to relax CO₂ targets. A planned prohibition on sales of new combustion engine cars in 2035 has faced intense lobbying from the automotive sector and resistance from member states with large automotive manufacturing.

Some senior officials have proposed PHEVs as a possible “flexibility” option to include in the legislation.

One external energy policy expert, who was unaffiliated with the research, called the report a “very useful contribution” after a long period in which parts of the car sector claimed there was too little data to properly assess real-world CO2 output.

“The results demonstrate, without question, that the difference in official and real-world PHEV energy use and CO₂ emissions is much, much larger than for petrol or conventional vehicles,” they stated. “All policy changes regarding PHEVs should be implemented with utmost care and in the light of this evidence.”