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Plug-in hybrid electric vehicles release nearly 5x more global warming emissions than lab-reported data indicate, as per a recent report.

Widening Gap In Lab and Actual Emissions

Statistics reveals that PHEVs release only 19% lower CO₂ than conventional petrol and diesel vehicles, according to analysis conducted by a advocacy organization. That contrasts sharply with laboratory tests, which assumed a 75% decrease in pollution.

Analysts studied data from onboard fuel consumption monitors of eight hundred thousand cars registered in Europe between 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, increased from three and a half times in 2021.

“Real-world emissions are rising, while official figures are decreasing,” stated a lead analyst involved in the study. “That discrepancy is widening and creates a serious problem. As a result, PHEVs pollute nearly as much as petrol cars.”

Primary Reasons Behind the Discrepancy

Researchers linked most of the difference to overestimates of the “electric driving share” – the ratio of miles travelled in battery power relative to total distance. The team found that only 27% of travel was completed in EV mode, while official estimates assumed over four-fifths.

Additionally, when operating in EV mode, emission amounts were well above lab estimates. This occurred because EV motors were insufficiently powerful enough to function alone, leading to engines burning gasoline for nearly one-third of the travel covered in EV mode.

Policy and Economic Implications

According to calculations, the underestimation of PHEV emissions allowed several large automaker groups to escape more than €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ standards.

Additionally, drivers of PHEVs would spend approximately €500 more per year in operating expenses than would be estimated under laboratory tests.

“The bold statements that manufacturers like to make about their plug-in hybrid cars are clearly way off the mark,” commented a transport analyst. “Buyers are being misled into believing that by buying a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are only slightly improved than standard gas and diesel cars in terms of fuel use, CO₂ emissions, and operating expenses.”

Political Discussion and Industry Lobbying

Hybrid cars have lately been brought back into policy debates as automakers have lobbied the EU to relax CO₂ standards. A planned ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with significant car industries.

Some high-level politicians have proposed plug-in hybrids as a potential “compromise” option to introduce in the regulation.

An independent energy economics expert, who was unaffiliated with the study, described the report a “highly valuable addition” after a long period in which parts of the car sector claimed there was too little data to properly assess real-world emissions.

“The results demonstrate, beyond any doubt, that the gap between official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or conventional cars,” they said. “All regulatory adjustments regarding PHEVs should be implemented with utmost caution and in the light of this data.”