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Plug-in hybrid cars emit nearly 5x more planet-heating emissions than lab-reported figures show, as per a recent analysis.

Widening Discrepancy Between Lab and Real-World Emissions

Statistics reveals that PHEVs release only one-fifth lower CO₂ than traditional petrol and diesel cars, according to analysis conducted by a advocacy organization. This differs sharply with lab estimates, which suggested a three-quarters reduction in pollution.

Analysts examined information from onboard fuel consumption meters of 800,000 vehicles registered in the EU from 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab estimates, up from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are falling,” stated a lead researcher participating in the report. “This gap is growing and poses a significant issue. As a result, PHEVs emit nearly as much as petrol cars.”

Key Factors Behind the Emissions Gap

Researchers linked the majority of the difference to overestimates of the “electric driving share” – the ratio of miles travelled in electric mode relative to overall distance. They determined that only 27% of driving was done in EV mode, whereas official assumptions suggested over four-fifths.

Additionally, when operating in electric mode, pollution levels were significantly higher than lab estimates. This happened because EV motors were not strong enough to operate alone, leading to combustion motors using fossil fuels for nearly one-third of the travel covered in EV mode.

Regulatory and Financial Consequences

According to calculations, the lowballing of PHEV CO2 output enabled several major automaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs would spend approximately €500 more annually in operating expenses than would be estimated under laboratory conditions.

“The bold statements that automakers like to make about their plug-in hybrid cars are clearly way off the truth,” stated a automotive expert. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are only slightly improved than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Pressure

Hybrid vehicles have recently been brought again into political discussions as automakers have pressed the EU to relax CO₂ standards. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced intense pressure from the car sector and resistance from member states with significant car industries.

Some high-level politicians have suggested PHEVs as a possible “flexibility” option to include in the legislation.

One independent energy policy expert, who was not involved with the research, called the analysis a “highly valuable addition” after a long period in which segments of the car industry argued there was too little data to properly assess real-world emissions.

“These findings demonstrate, beyond any doubt, that the difference in official and actual PHEV fuel consumption and CO₂ output is significantly larger than for gasoline or conventional cars,” the expert stated. “Any regulatory changes regarding PHEVs should be implemented with utmost caution and considering that evidence.”