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Plug-in hybrid cars produce almost 5x more global warming pollution than lab-reported figures indicate, according to a recent report.

Widening Discrepancy In Official and Real-World CO2 Output

Statistics shows that PHEVs emit only 19% lower CO₂ than conventional petrol and diesel cars, according to analysis conducted by a advocacy organization. That contrasts sharply with lab estimates, which suggested a three-quarters decrease in pollution.

Researchers studied data from onboard energy use monitors of 800,000 cars sold in Europe between 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, up from three and a half times in 2021.

“Actual emissions are increasing, while official figures are decreasing,” stated a senior analyst involved in the study. “That gap is widening and creates a serious issue. Consequently, PHEVs pollute almost as heavily as petrol vehicles.”

Key Factors Behind the Discrepancy

Researchers attributed most of the gap to inflated estimates of the “utility factor” – the percentage of kilometers driven in electric mode compared to overall mileage. They found that only 27% of driving was done in electric mode, whereas lab assumptions suggested over four-fifths.

Additionally, when operating in electric mode, emission amounts were well above lab projections. This happened because electric motors were insufficiently powerful sufficient to function independently, resulting to engines burning fossil fuels for almost a third of the travel covered in EV mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV CO2 output allowed four major automaker companies to escape more than €5bn in penalties from 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs could spend approximately €500 extra per year in running costs than would be estimated under laboratory tests.

“The bold statements that manufacturers like to make about their plug-in hybrid vehicles are clearly way off the truth,” stated a transport analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and saving money. In reality, PHEVs are little improved than standard petrol and diesel cars in terms of fuel use, CO₂ emissions, and operating expenses.”

Policy Discussion and Automotive Lobbying

Hybrid vehicles have lately been brought again into political discussions as automakers have pressed the European Union to weaken CO₂ targets. 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 high-level politicians have proposed plug-in hybrids as a possible “flexibility” option to include in the regulation.

One independent energy economics specialist, who was unaffiliated with the research, described the analysis a “highly valuable contribution” after years in which parts of the car sector claimed there was too little information to accurately assess real-world emissions.

“The results demonstrate, beyond any doubt, that the gap in official and real-world PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or conventional cars,” the expert stated. “All regulatory changes regarding PHEVs should be implemented with utmost caution and in the light of that evidence.”