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Plug-in hybrid cars release almost 5x more planet-heating emissions than lab-reported data indicate, as per a new analysis.

Widening Gap In Official and Real-World Emissions

Statistics shows that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel vehicles, based on research carried out by a advocacy organization. This contrasts significantly with lab estimates, which suggested a 75% decrease in pollution.

Analysts studied data from onboard fuel consumption monitors of eight hundred thousand vehicles sold in the EU between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official estimates, up from three and a half times in 2021.

“Real-world emissions are increasing, while official figures are falling,” stated a lead analyst involved in the report. “That discrepancy is widening and creates a serious problem. As a result, PHEVs emit nearly as much as gasoline cars.”

Key Reasons Behind the Discrepancy

Analysts linked most of the difference to inflated estimates of the “utility factor” – the percentage of miles travelled in electric power relative to overall distance. The team found that just a quarter of driving was completed in electric mode, whereas official estimates assumed over four-fifths.

Even, when operating in electric mode, emission levels were well above official projections. This happened because EV motors were not strong enough to operate independently, resulting to engines burning gasoline for nearly a third of the distance covered in electric mode.

Regulatory and Financial Consequences

Based on estimates, the lowballing of PHEV emissions enabled several large automaker companies to avoid over €5bn in fines between 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could pay approximately €500 more annually in operating costs than is estimated under laboratory tests.

“The bold statements that automakers like to make about their plug-in hybrid cars are obviously way off the truth,” stated a transport analyst. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little improved than regular gas and diesel cars in terms of fuel use, CO₂ production, and running costs.”

Political Discussion and Industry Pressure

Plug-in hybrid cars have recently been drawn again into policy debates as carmakers have pressed the European Union to weaken CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced heavy lobbying from the automotive sector and resistance from member states with significant automotive industries.

Some senior officials have suggested plug-in hybrids as a potential “flexibility” option to include in the legislation.

One external energy policy expert, who was not involved with the study, described the report a “very useful addition” after years in which segments of the car industry argued there was insufficient data to properly evaluate real-world emissions.

“These findings demonstrate, without question, that the gap between lab and actual PHEV energy use and CO₂ emissions is significantly greater than for gasoline or diesel vehicles,” they stated. “All policy changes regarding PHEVs should be implemented with utmost caution and considering that data.”