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Plug-in hybrid electric vehicles emit almost five times greater planet-heating pollution than lab-reported data indicate, according to a recent analysis.

Widening Gap In Official and Real-World CO2 Output

Data reveals that PHEVs release just one-fifth less CO₂ than traditional gas and diesel vehicles, based on analysis conducted by a advocacy organization. This contrasts significantly with laboratory tests, which suggested a 75% decrease in pollution.

Analysts examined information from onboard fuel consumption meters of 800,000 cars registered in the EU from 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported emissions are decreasing,” said a lead analyst participating in the report. “That gap is growing and creates a significant issue. Consequently, PHEVs pollute nearly as much as petrol cars.”

Primary Factors Behind the Emissions Gap

Researchers attributed most of the gap to overestimates of the “utility factor” – the ratio of kilometers driven in battery power compared to total distance. They found that just 27% of travel was done in electric mode, while lab assumptions assumed over four-fifths.

Even, when running in electric mode, emission levels were significantly higher than lab estimates. This happened because EV motors were insufficiently powerful sufficient to function alone, resulting to combustion motors using fossil fuels for nearly a third of the distance covered in electric mode.

Regulatory and Economic Implications

According to estimates, the lowballing of PHEV emissions allowed several large carmaker 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 could spend approximately €500 extra annually in running expenses than is estimated under lab tests.

“The strong statements that automakers like to make about their plug-in hybrid cars are clearly far from the mark,” commented a automotive expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the planet and saving money. Actually, PHEVs are little better than regular gas and diesel cars in terms of energy use, CO₂ production, and operating expenses.”

Policy Debate and Industry Pressure

Hybrid vehicles have lately been brought back into political discussions as automakers have lobbied the European Union to relax CO₂ targets. A planned ban on sales of new combustion engine vehicles in 2035 has faced intense pressure from the automotive sector and resistance from EU countries with large automotive industries.

Several senior politicians have suggested PHEVs as a potential “flexibility” option to introduce in the regulation.

One external energy economics specialist, who was unaffiliated with the research, called the analysis a “highly valuable contribution” after a long period in which segments of the automotive industry claimed there was insufficient information to properly evaluate real-world emissions.

“The results demonstrate, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ emissions is significantly larger than for gasoline or conventional vehicles,” the expert said. “All policy adjustments concerning PHEVs should be made with extreme caution and in the light of this data.”