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Plug-in hybrid electric vehicles release almost 5x more global warming emissions than lab-reported data show, as per a recent analysis.

Widening Gap Between Lab and Actual Emissions

Statistics shows that PHEVs release just 19% lower CO₂ than conventional petrol and diesel cars, based on research conducted by a non-profit organization. This differs significantly with laboratory tests, which suggested a 75% decrease in pollution.

Researchers studied information from in-vehicle fuel consumption meters of 800,000 vehicles sold in Europe from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official figures are decreasing,” stated a lead researcher involved in the study. “This gap is widening and poses a significant problem. As a result, PHEVs emit almost as heavily as gasoline vehicles.”

Key Factors Behind the Discrepancy

Researchers linked most of the gap to overestimates of the “utility factor” – the ratio of kilometers travelled in electric power compared to overall distance. The team found that only 27% of driving was done in EV mode, while lab assumptions assumed 84%.

Even, when operating in EV mode, emission levels were well above official estimates. This happened because electric motors were not strong enough to operate independently, leading to engines burning gasoline for almost a third of the travel completed in electric mode.

Regulatory and Economic Implications

Based on calculations, the underestimation of PHEV emissions allowed four major carmaker companies to avoid more than €5bn in fines between 2021 and 2023, by falsely simplifying adherence with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs would spend approximately €500 extra per year in operating costs than would be assumed under laboratory conditions.

“The bold statements that automakers often promote about their plug-in hybrid vehicles are obviously far from the truth,” stated a automotive analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little better than standard gas and diesel vehicles in terms of energy consumption, CO₂ production, and operating costs.”

Political Debate and Industry Pressure

Plug-in hybrid cars have lately been brought again into political discussions as carmakers have pressed the European Union to weaken CO₂ standards. A proposed prohibition on new combustion engine vehicles in 2035 has faced heavy lobbying from the automotive industry and resistance from member states with significant car industries.

Some senior officials have suggested PHEVs as a potential “flexibility” solution to include in the regulation.

An independent energy economics specialist, who was unaffiliated with the study, called the analysis a “highly valuable addition” after years in which segments of the car sector argued there was too little information to accurately assess actual CO2 output.

“These findings show, beyond any doubt, that the gap in lab and real-world PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or conventional cars,” they stated. “Any policy adjustments regarding PHEVs should be made with utmost caution and considering this data.”