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Plug-in hybrid electric vehicles emit almost 5x more global warming pollution than lab-reported figures show, as per a recent analysis.

Growing Gap In Official and Real-World Emissions

Statistics reveals that PHEVs release just one-fifth lower CO₂ than traditional gas and diesel cars, based on research carried out by a advocacy group. That contrasts significantly with lab tests, which suggested a three-quarters decrease in emissions.

Analysts studied information from in-vehicle energy use monitors of eight hundred thousand vehicles registered in the EU between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” stated a senior researcher involved in the study. “This gap is growing and creates a significant problem. Consequently, PHEVs emit almost as heavily as gasoline vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts attributed most of the gap to overestimates of the “utility factor” – the percentage of miles driven in battery power relative to overall distance. The team determined that only 27% of travel was completed in electric mode, whereas official estimates assumed over four-fifths.

Additionally, when operating in EV mode, emission amounts were significantly higher than official estimates. This occurred because EV motors were insufficiently powerful enough to function independently, resulting to engines using gasoline for nearly one-third of the distance covered in electric mode.

Policy and Financial Implications

Based on estimates, the underestimation of PHEV emissions enabled four major carmaker groups to escape over €5bn in penalties between 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs could spend about €500 more annually in operating expenses than is estimated under laboratory conditions.

“The bold claims that automakers like to make about their plug-in hybrid vehicles are clearly way off the truth,” commented a automotive analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the environment and saving money. Actually, PHEVs are only slightly improved than regular gas and diesel vehicles in terms of energy use, CO₂ production, and running costs.”

Policy Discussion and Industry Pressure

Hybrid cars have lately been drawn back into policy debates as automakers have lobbied the European Union to relax CO₂ targets. A proposed ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the automotive industry and resistance from member states with large automotive industries.

Several senior politicians have suggested PHEVs as a possible “flexibility” solution to include in the regulation.

An independent energy policy specialist, who was unaffiliated with the study, called the report a “very useful addition” after years in which segments of the car sector claimed there was too little information to accurately assess actual CO2 output.

“The results demonstrate, beyond any doubt, that the gap in official and actual PHEV energy use and CO₂ output is much, much larger than for gasoline or diesel vehicles,” the expert stated. “Any policy changes regarding PHEVs should be made with extreme care and in the light of that data.”