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PHEVs produce almost five times greater planet-heating emissions than lab-reported figures show, as per a new analysis.

Growing Discrepancy In Official and Real-World Emissions

Data reveals that PHEVs emit only 19% less CO₂ than conventional gas and diesel cars, based on analysis conducted by a advocacy organization. That differs sharply with laboratory tests, which suggested a three-quarters decrease in emissions.

Analysts studied information from in-vehicle energy use monitors of eight hundred thousand cars sold in Europe from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than official figures, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while official figures are falling,” said a lead researcher involved in the report. “This discrepancy is widening and poses a significant issue. Consequently, PHEVs emit nearly as heavily as petrol vehicles.”

Primary Factors Driving the Discrepancy

Analysts linked the majority of the difference to inflated estimates of the “utility factor” – the percentage of miles driven in electric power relative to total mileage. The team determined that only a quarter of driving was completed in electric mode, while official assumptions assumed 84%.

Even, when running in electric mode, pollution levels were well above official projections. This occurred because electric motors were not strong enough to function alone, leading to engines burning gasoline for almost a third of the travel covered in EV mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV emissions allowed four major carmaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially easing compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs could pay approximately €500 extra annually in running costs than is assumed under lab tests.

“The bold statements that automakers often promote about their PHEV vehicles are obviously far from the mark,” stated a automotive analyst. “Consumers are being duped into thinking that by buying a PHEV, they are helping the environment and cutting money. Actually, PHEVs are little better than standard petrol and diesel cars in terms of fuel consumption, CO₂ emissions, and running expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid cars have lately been brought back into political debates as carmakers have lobbied the EU to relax CO₂ targets. A planned ban on sales of new combustion engine cars in 2035 has faced intense pressure from the car sector and opposition from member states with large car manufacturing.

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

One independent energy economics specialist, who was unaffiliated with the study, called the analysis a “very useful contribution” after years in which parts of the car industry claimed there was too little data to properly assess real-world emissions.

“These findings show, without question, that the gap in official and real-world PHEV energy use and CO₂ output is much, much greater than for gasoline or diesel vehicles,” they stated. “Any policy changes concerning PHEVs should be implemented with utmost caution and considering that data.”