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Plug-in hybrid electric vehicles produce nearly 5x greater global warming pollution than lab-reported figures indicate, as per a recent report.

Growing Gap In Official and Actual CO2 Output

Statistics shows that PHEVs emit just one-fifth less CO₂ than traditional gas and diesel vehicles, based on research carried out by a advocacy organization. That differs sharply with laboratory estimates, which assumed a 75% reduction in emissions.

Analysts examined data from onboard energy use monitors of 800,000 vehicles sold in Europe from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are decreasing,” stated a lead researcher participating in the study. “That discrepancy is widening and creates a serious problem. Consequently, PHEVs emit almost as much as petrol cars.”

Primary Reasons Driving the Discrepancy

Researchers attributed most of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in electric power relative to overall mileage. They determined that just 27% of travel was completed in electric mode, whereas official estimates suggested over four-fifths.

Even, when running in EV mode, emission amounts were well above lab estimates. That occurred because EV motors were insufficiently powerful enough to operate alone, leading to engines burning gasoline for almost one-third of the travel covered in EV mode.

Regulatory and Economic Consequences

Based on calculations, the lowballing of PHEV CO2 output enabled several large carmaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially easing compliance with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs could pay approximately €500 more per year in running expenses than is assumed under lab tests.

“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 purchasing a PHEV, they are helping the planet and saving money. Actually, PHEVs are little better than standard gas and diesel cars in terms of fuel use, CO₂ emissions, and running costs.”

Political Discussion and Automotive Lobbying

Plug-in hybrid vehicles have recently been brought back into political discussions as automakers have pressed the EU to weaken CO₂ standards. A proposed ban on new combustion engine cars in 2035 has faced intense lobbying from the automotive sector and resistance from EU countries with large car industries.

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

One external energy economics expert, who was not involved with the study, described the analysis a “very useful contribution” after years in which segments of the car industry claimed there was too little data to accurately evaluate actual emissions.

“These findings demonstrate, beyond any doubt, that the difference in official and real-world PHEV energy use and CO₂ output is significantly larger than for petrol or diesel cars,” the expert stated. “Any policy adjustments concerning PHEVs should be made with utmost caution and considering that data.”