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

Widening Gap In Official and Real-World Emissions

Statistics shows that PHEVs release just one-fifth lower CO₂ than conventional petrol and diesel vehicles, based on research conducted by a advocacy organization. This differs sharply with lab estimates, which suggested a three-quarters reduction in pollution.

Analysts examined data from in-vehicle fuel consumption monitors of 800,000 cars registered in the EU between 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, up from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are decreasing,” said a senior analyst participating in the study. “That discrepancy is widening and creates a serious issue. Consequently, PHEVs emit almost as heavily as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Researchers linked the majority of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in battery power compared to overall mileage. They determined that just 27% of driving was done in electric mode, while lab estimates assumed over four-fifths.

Additionally, when operating in EV mode, pollution levels were significantly higher than lab estimates. That occurred because EV motors were not strong sufficient to function independently, resulting to engines using gasoline for nearly one-third of the distance covered in EV mode.

Policy and Economic Implications

Based on estimates, the lowballing of PHEV emissions enabled four major automaker companies to avoid more than €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs could spend approximately €500 extra per year in running costs than would be estimated under lab conditions.

“The bold claims that manufacturers often promote about their plug-in hybrid vehicles are obviously far from the truth,” commented a automotive expert. “Consumers are being duped into thinking that by buying a PHEV, they are helping the environment and saving money. Actually, PHEVs are only slightly better than regular gas and diesel cars in terms of fuel use, CO₂ emissions, and operating expenses.”

Political Discussion and Automotive Pressure

Plug-in hybrid vehicles have recently been brought back into political discussions as automakers have lobbied the European Union to weaken CO₂ standards. A planned ban on sales of new internal combustion vehicles in 2035 has faced intense pressure from the automotive sector and resistance from EU countries with significant automotive industries.

Some high-level politicians have proposed PHEVs as a possible “compromise” solution to include in the regulation.

An external energy economics expert, who was not involved with the study, described the analysis a “highly valuable contribution” after years in which parts of the automotive sector argued there was insufficient information to accurately assess actual emissions.

“These findings show, without question, that the gap in lab and actual PHEV energy use and CO₂ emissions is significantly greater than for petrol or conventional vehicles,” they stated. “Any policy changes regarding PHEVs should be made with utmost caution and in the light of this data.”