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PHEVs produce almost five times more global warming emissions than lab-reported figures show, as per a new analysis.

Widening Gap In Lab and Real-World Emissions

Data reveals that PHEVs release just one-fifth less CO₂ than conventional gas and diesel cars, according to analysis conducted by a non-profit group. This contrasts significantly with lab tests, which suggested a 75% reduction in pollution.

Analysts examined data from in-vehicle energy use monitors of 800,000 cars sold in the EU from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official emissions are decreasing,” stated a senior researcher participating in the study. “That gap is growing and poses a serious problem. As a result, PHEVs pollute almost as much as petrol vehicles.”

Primary Factors Behind the Discrepancy

Analysts attributed most of the difference to inflated estimates of the “electric driving share” – the ratio of miles travelled in electric power compared to total distance. The team determined that only a quarter of travel was completed in EV mode, while official estimates assumed over four-fifths.

Additionally, when operating in electric mode, emission levels were well above lab projections. This happened because electric motors were insufficiently powerful enough to function independently, resulting to combustion motors burning gasoline for nearly a third of the travel covered in electric mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV CO2 output allowed four large carmaker companies to escape more than €5bn in penalties between 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ targets.

Additionally, drivers of PHEVs could pay about €500 extra annually in operating expenses than would be assumed under lab conditions.

“The bold statements that manufacturers often promote about their plug-in hybrid cars are clearly far from the truth,” stated a transport expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. In reality, PHEVs are only slightly better than regular gas and diesel cars in terms of energy use, CO₂ production, and running costs.”

Policy Debate and Industry Lobbying

Plug-in hybrid vehicles have lately been drawn again into policy debates as carmakers have lobbied the EU to relax CO₂ standards. A planned ban on new combustion engine vehicles in 2035 has faced intense pressure from the automotive industry and resistance from EU countries with significant car manufacturing.

Several senior politicians have proposed PHEVs as a potential “flexibility” solution to include in the legislation.

One independent energy policy specialist, who was unaffiliated with the research, called the report a “highly valuable contribution” after a long period in which segments of the car industry claimed there was too little information to accurately assess actual CO2 output.

“The results demonstrate, beyond any doubt, that the gap in official and actual PHEV energy use and CO₂ emissions is much, much larger than for gasoline or conventional vehicles,” they stated. “Any regulatory changes regarding PHEVs should be made with utmost caution and in the light of this evidence.”