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PHEVs emit almost five times more planet-heating emissions than lab-reported figures indicate, according to a new report.

Widening Gap In Official and Actual CO2 Output

Statistics shows that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel vehicles, according to research carried out by a advocacy group. This contrasts significantly with laboratory tests, which assumed a three-quarters decrease in emissions.

Researchers examined data from onboard energy use monitors of 800,000 cars registered in Europe from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, up from three and a half times in 2021.

“Actual CO2 output are rising, while official emissions are falling,” said a senior researcher involved in the study. “This discrepancy is widening and poses a significant issue. Consequently, PHEVs emit nearly as heavily as petrol cars.”

Primary Factors Driving the Emissions Gap

Researchers linked the majority of the difference to inflated estimates of the “electric driving share” – the percentage of miles driven in battery mode relative to total distance. They determined that only a quarter of travel was done in EV mode, whereas official estimates suggested over four-fifths.

Additionally, when operating in EV mode, emission amounts were well above lab projections. This occurred because electric motors were insufficiently powerful sufficient to operate alone, resulting to combustion motors burning fossil fuels for nearly one-third of the distance covered in electric mode.

Regulatory and Economic Consequences

Based on estimates, the lowballing of PHEV CO2 output allowed four major automaker companies to avoid over €5bn in fines from 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs could pay about €500 more annually in operating expenses than would be estimated under lab conditions.

“The bold statements that automakers often promote about their PHEV cars are clearly far from the mark,” stated a automotive analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the environment and saving costs. In reality, PHEVs are little improved than standard petrol and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Discussion and Industry Pressure

Hybrid cars have lately been drawn again into policy debates as automakers have lobbied the EU to relax CO₂ targets. A proposed prohibition on sales of new internal combustion cars in 2035 has faced intense lobbying from the car sector and resistance from EU countries with significant automotive manufacturing.

Several high-level officials have suggested plug-in hybrids as a possible “flexibility” solution to introduce in the regulation.

An external energy policy expert, who was unaffiliated with the research, called the report a “highly valuable contribution” after a long period in which segments of the automotive sector argued there was insufficient data to properly evaluate actual emissions.

“These findings show, without question, that the difference in lab and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or diesel vehicles,” they stated. “All regulatory changes regarding PHEVs should be implemented with utmost caution and in the light of that data.”