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Plug-in hybrid cars produce nearly 5x more global warming pollution than lab-reported figures show, as per a recent report.

Growing Discrepancy Between Official and Actual Emissions

Statistics reveals that PHEVs emit just 19% less CO₂ than conventional gas and diesel vehicles, based on research carried out by a non-profit group. That contrasts sharply with lab estimates, which suggested a 75% reduction in pollution.

Researchers examined data from in-vehicle fuel consumption meters of eight hundred thousand cars sold in the EU between 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, increased from 3.5 times in 2021.

“Real-world emissions are rising, while official figures are falling,” stated a lead researcher involved in the report. “That discrepancy is widening and poses a serious issue. As a result, PHEVs pollute almost as heavily as petrol vehicles.”

Primary Factors Behind the Discrepancy

Researchers linked most of the difference to inflated estimates of the “utility factor” – the percentage of miles travelled in electric mode compared to overall mileage. The team found that only a quarter of driving was done in EV mode, whereas lab assumptions assumed 84%.

Additionally, when running in EV mode, pollution levels were significantly higher than official projections. That occurred because EV motors were insufficiently powerful sufficient to function alone, leading to combustion motors using gasoline for almost a third of the travel completed in EV mode.

Policy and Financial Implications

Based on calculations, the underestimation of PHEV emissions allowed several large automaker companies to escape more than €5bn in fines from 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could pay about €500 more per year in operating expenses than would be assumed under lab tests.

“The bold claims that automakers often promote about their plug-in hybrid cars are obviously far from the truth,” stated a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are only slightly improved than standard petrol and diesel cars in terms of fuel use, CO₂ emissions, and operating costs.”

Political Debate and Automotive Pressure

Hybrid vehicles have recently been drawn again into policy discussions as automakers have lobbied the EU to relax CO₂ standards. A planned ban on sales of new internal combustion cars in 2035 has faced intense pressure from the automotive sector and resistance from member states with large car industries.

Several senior politicians have suggested PHEVs as a possible “flexibility” option to include in the legislation.

An external energy policy expert, who was unaffiliated with the research, described the report a “highly valuable addition” after a long period in which parts of the automotive sector claimed there was too little information to properly evaluate real-world CO2 output.

“These findings demonstrate, without question, that the gap between lab and real-world PHEV energy use and CO₂ emissions is significantly greater than for gasoline or conventional cars,” the expert said. “All regulatory changes regarding PHEVs should be made with extreme caution and considering that data.”