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Plug-in hybrid cars produce nearly 5x greater planet-heating pollution than official figures show, as per a recent analysis.

Growing Gap In Lab and Real-World CO2 Output

Statistics shows that PHEVs emit just one-fifth lower CO₂ than conventional petrol and diesel cars, based on analysis conducted by a non-profit organization. This contrasts sharply with lab tests, which suggested a three-quarters decrease in pollution.

Researchers studied data from in-vehicle 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 nearly five times greater than official figures, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported figures are falling,” stated a senior analyst involved in the report. “This gap is growing and creates a serious issue. Consequently, PHEVs emit nearly as much as gasoline cars.”

Key Reasons Driving the Emissions Gap

Analysts linked the majority of the gap to inflated estimates of the “utility factor” – the percentage of miles travelled in battery mode relative to total distance. They found that just 27% of driving was done in EV mode, whereas lab estimates assumed 84%.

Additionally, when operating in EV mode, pollution amounts were well above official estimates. That occurred because electric motors were not strong sufficient to function independently, leading to engines burning gasoline for nearly one-third of the distance completed in EV mode.

Regulatory and Economic Consequences

According to calculations, the lowballing of PHEV emissions allowed several major automaker groups to escape over €5bn in penalties from 2021 and 2023, by falsely simplifying adherence with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs could spend about €500 more annually in operating costs than is assumed under lab conditions.

“The strong statements that manufacturers often promote about their plug-in hybrid cars are clearly way off the mark,” commented a transport analyst. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are only slightly improved than standard gas and diesel vehicles in terms of energy use, CO₂ emissions, and operating costs.”

Policy Debate and Automotive Pressure

Hybrid vehicles have recently been drawn back into policy discussions 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 lobbying from the car sector and resistance from EU countries with significant car industries.

Several high-level officials have suggested plug-in hybrids as a potential “flexibility” option to include in the legislation.

One independent energy economics specialist, who was unaffiliated with the study, described the report a “highly valuable contribution” after a long period in which segments of the automotive industry argued there was too little information to properly evaluate actual CO2 output.

“The results demonstrate, without question, that the gap between lab and real-world PHEV fuel consumption and CO₂ emissions is much, much greater than for gasoline or conventional vehicles,” they stated. “Any regulatory adjustments regarding PHEVs should be implemented with utmost caution and considering that data.”