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PHEVs emit almost five times more global warming emissions than official data show, as per a recent analysis.

Growing Gap Between Lab and Real-World Emissions

Data shows that PHEVs release only 19% less CO₂ than traditional petrol and diesel vehicles, based on analysis carried out by a non-profit group. That contrasts sharply with lab estimates, which assumed a three-quarters reduction in emissions.

Researchers examined data from in-vehicle energy use monitors of 800,000 vehicles sold in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, up from 3.5 times in 2021.

“Real-world CO2 output are rising, while official figures are decreasing,” stated a lead researcher participating in the study. “This discrepancy is growing and creates a serious problem. As a result, PHEVs pollute nearly as much as gasoline vehicles.”

Primary Reasons Behind the Discrepancy

Researchers linked the majority of the difference to overestimates of the “electric driving share” – the ratio of miles driven in electric mode compared to total distance. The team determined that just a quarter of driving was done in EV mode, while official estimates suggested over four-fifths.

Even, when running in electric mode, pollution levels were significantly higher than official estimates. This occurred because EV motors were insufficiently powerful enough to operate alone, leading to combustion motors burning gasoline for almost one-third of the distance completed in electric mode.

Regulatory and Economic Implications

According to estimates, the underestimation of PHEV CO2 output allowed several large carmaker companies to escape more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs would pay approximately €500 extra annually in operating costs than is assumed under laboratory tests.

“The strong claims that automakers like to make about their PHEV vehicles are clearly far from the truth,” commented a transport analyst. “Buyers are being duped into believing that by purchasing a PHEV, they are helping the environment and cutting money. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of energy consumption, CO₂ emissions, and operating costs.”

Political Debate and Industry Lobbying

Hybrid cars have lately been drawn back into policy debates as carmakers have lobbied the EU to weaken CO₂ standards. A planned ban on sales of new combustion engine vehicles in 2035 has faced heavy lobbying from the automotive industry and opposition from member states with significant car industries.

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

An external energy policy specialist, who was unaffiliated with the study, called the report a “highly valuable contribution” after years in which parts of the automotive industry argued there was too little information to properly evaluate real-world CO2 output.

“These findings demonstrate, without question, that the gap in official and real-world PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or diesel cars,” they said. “All regulatory adjustments concerning PHEVs should be implemented with utmost caution and in the light of this evidence.”