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PHEVs produce almost five times more global warming pollution than lab-reported figures show, according to a recent report.

Widening Discrepancy In Official and Actual Emissions

Statistics shows that PHEVs release just one-fifth less CO₂ than traditional petrol and diesel cars, according to research conducted by a non-profit organization. This contrasts significantly with lab tests, which assumed a three-quarters reduction in emissions.

Analysts studied data from in-vehicle energy use monitors of 800,000 cars sold in the EU from 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official estimates, up from three and a half times in 2021.

“Real-world emissions are increasing, while official figures are falling,” said a lead analyst participating in the study. “This gap is growing and creates a significant problem. Consequently, PHEVs emit almost as much as petrol vehicles.”

Primary Reasons Behind the Discrepancy

Analysts linked the majority of the gap to inflated estimates of the “utility factor” – the percentage of kilometers driven in electric power relative to overall mileage. They determined that only a quarter of driving was completed in electric mode, while official estimates suggested 84%.

Additionally, when operating in electric mode, emission levels were significantly higher than lab estimates. That occurred because EV motors were not strong sufficient to function independently, resulting to combustion motors using fossil fuels for nearly a third of the distance completed in electric mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV emissions enabled several large automaker companies to escape over €5bn in penalties from 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs could spend approximately €500 extra annually in operating costs than would be estimated under lab tests.

“The bold statements that manufacturers often promote about their PHEV vehicles are clearly way off the truth,” stated a transport analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are only slightly improved than standard petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and running expenses.”

Political Debate and Industry Pressure

Plug-in hybrid cars have recently been drawn back into political debates as carmakers have lobbied the European Union to weaken CO₂ standards. A planned ban on new internal combustion cars in 2035 has faced intense pressure from the car industry and resistance from EU countries with large car manufacturing.

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

An independent energy economics specialist, who was unaffiliated with the research, called the report a “very useful addition” after a long period in which parts of the car sector claimed there was insufficient information to properly evaluate real-world emissions.

“The results show, beyond any doubt, that the gap between official and actual PHEV energy use and CO₂ output is significantly larger than for petrol or diesel vehicles,” they said. “Any regulatory changes regarding PHEVs should be made with extreme caution and in the light of this evidence.”