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Plug-in hybrid electric vehicles produce nearly five times more global warming pollution than official data show, as per a new analysis.

Widening Gap Between Official and Real-World CO2 Output

Data reveals that PHEVs release only one-fifth less CO₂ than traditional gas and diesel cars, according to analysis conducted by a non-profit organization. That contrasts significantly with laboratory estimates, which assumed a three-quarters reduction in emissions.

Analysts examined information from in-vehicle fuel consumption monitors of eight hundred thousand vehicles sold in Europe between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official figures, up from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported figures are decreasing,” stated a lead analyst participating in the study. “That gap is widening and creates a significant problem. As a result, PHEVs emit nearly as heavily as petrol cars.”

Key Factors Behind the Discrepancy

Analysts attributed the majority of the gap to inflated estimates of the “utility factor” – the ratio of kilometers driven in battery power relative to overall mileage. The team found that just 27% of travel was completed in electric mode, whereas lab assumptions suggested over four-fifths.

Even, when operating in EV mode, emission amounts were well above lab projections. That happened because electric motors were not strong enough to function alone, resulting to engines burning gasoline for almost a third of the distance covered in EV mode.

Regulatory and Financial Implications

According to calculations, the underestimation of PHEV emissions allowed four major automaker companies to avoid more than €5bn in fines between 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ targets.

Furthermore, drivers of PHEVs would pay approximately €500 more per year in running expenses than would be assumed under lab conditions.

“The bold statements that automakers often promote about their PHEV vehicles are obviously far from the truth,” stated a transport expert. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are little improved than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating expenses.”

Political Discussion and Automotive Pressure

Plug-in hybrid cars have lately been brought again into policy discussions as automakers have pressed the EU to weaken CO₂ standards. A proposed ban on new internal combustion cars in 2035 has faced intense pressure from the automotive industry and opposition from member states with significant automotive manufacturing.

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

One independent energy economics specialist, who was unaffiliated with the research, described the analysis a “very useful addition” after a long period in which segments of the car industry argued there was too little data to accurately evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the gap between official and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for gasoline or conventional cars,” they stated. “All policy adjustments regarding PHEVs should be implemented with utmost care and considering this evidence.”