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Plug-in hybrid cars produce almost 5x greater planet-heating emissions than lab-reported figures show, according to a new analysis.

Growing Discrepancy In Official and Actual CO2 Output

Statistics shows that PHEVs release just one-fifth lower CO₂ than traditional gas and diesel vehicles, based on research conducted by a non-profit organization. This contrasts significantly with lab estimates, which assumed a three-quarters decrease in emissions.

Analysts studied data from onboard fuel consumption monitors of eight hundred thousand cars registered in the EU between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, increased from 3.5 times in 2021.

“Actual emissions are rising, while official figures are decreasing,” stated a senior analyst involved in the report. “This discrepancy is growing and poses a serious issue. As a result, PHEVs pollute nearly as much as petrol vehicles.”

Key Reasons Behind the Discrepancy

Researchers attributed the majority of the difference to inflated estimates of the “utility factor” – the percentage of miles travelled in battery mode relative to overall mileage. They found that just a quarter of travel was done in EV mode, while lab assumptions suggested 84%.

Additionally, when operating in electric mode, pollution amounts were significantly higher than official estimates. This occurred because EV motors were not strong enough to function independently, resulting to engines using gasoline for nearly one-third of the distance covered in electric mode.

Policy and Economic Consequences

According to estimates, the lowballing of PHEV emissions allowed four large automaker groups to avoid over €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs could spend approximately €500 extra annually in operating costs than would be assumed under laboratory tests.

“The strong claims that automakers often promote about their PHEV vehicles are obviously way off the mark,” stated a automotive expert. “Consumers are being duped into believing that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little improved than regular gas and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating expenses.”

Political Discussion and Industry Lobbying

Hybrid vehicles have lately been brought back into political debates as carmakers have pressed the EU to relax CO₂ targets. A proposed prohibition on new combustion engine vehicles in 2035 has faced intense pressure from the automotive sector and resistance from EU countries with large automotive manufacturing.

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

An independent energy economics specialist, who was not involved with the study, described the report a “highly valuable contribution” after years in which segments of the automotive sector claimed there was too little information to accurately assess real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for petrol or diesel vehicles,” they stated. “Any policy adjustments concerning PHEVs should be made with extreme care and in the light of this evidence.”