Plug-in Hybrid Vehicles Pollute Almost as Much as Gasoline Cars, Study Reveals

Plug-in hybrid cars produce nearly five times greater planet-heating pollution than official data show, according to a recent report.

Growing Discrepancy Between Official and Actual CO2 Output

Data reveals that PHEVs emit just 19% less CO₂ than conventional petrol and diesel cars, according to research carried out by a advocacy group. That contrasts significantly with lab estimates, which suggested a three-quarters reduction in pollution.

Researchers examined information from onboard fuel consumption monitors of 800,000 cars registered in the EU between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” said a lead analyst participating in the study. “This discrepancy is widening and creates a significant problem. Consequently, PHEVs pollute nearly as much as petrol vehicles.”

Primary Factors Behind the Discrepancy

Analysts linked most of the gap to overestimates of the “utility factor” – the ratio of miles travelled in battery power compared to overall distance. The team determined that just a quarter of driving was done in EV mode, whereas official assumptions suggested over four-fifths.

Additionally, when operating in electric mode, emission amounts were well above official projections. This occurred because electric motors were insufficiently powerful sufficient to function alone, resulting to combustion motors using gasoline for nearly a third of the travel covered in electric mode.

Regulatory and Economic Consequences

Based on calculations, the lowballing of PHEV CO2 output allowed several large automaker companies to avoid more than €5bn in fines from 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs would spend approximately €500 more annually in running expenses than is assumed under lab tests.

“The strong statements that manufacturers like to make about their PHEV cars are clearly way off the mark,” stated a automotive expert. “Consumers are being duped into believing that by buying a PHEV, they are helping the planet and saving money. Actually, PHEVs are little improved than regular petrol and diesel vehicles in terms of energy consumption, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have recently been brought again into political debates as automakers have pressed the EU to weaken CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced intense lobbying from the automotive sector and resistance from member states with significant automotive industries.

Several high-level politicians have suggested PHEVs as a potential “compromise” option to include in the legislation.

One independent energy policy expert, who was unaffiliated with the study, described the report a “highly valuable contribution” after a long period in which segments of the automotive industry claimed there was insufficient information to accurately assess real-world CO2 output.

“These findings show, without question, that the gap between official and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for gasoline or conventional vehicles,” the expert said. “Any regulatory adjustments regarding PHEVs should be made with utmost care and considering this evidence.”