🔗 Share this article

Plug-in hybrid electric vehicles emit nearly five times greater global warming pollution than lab-reported figures show, according to a new report.

Growing Gap Between Lab and Real-World Emissions

Statistics shows that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel cars, based on research conducted by a advocacy group. That contrasts significantly with lab estimates, which suggested a three-quarters decrease in emissions.

Analysts examined data from in-vehicle fuel consumption monitors of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab estimates, up from 3.5 times in 2021.

“Real-world emissions are increasing, while official emissions are falling,” said a senior analyst involved in the report. “This discrepancy is growing and poses a serious issue. As a result, PHEVs emit almost as heavily as gasoline vehicles.”

Key Factors Behind the Emissions Gap

Researchers linked the majority of the gap to overestimates of the “utility factor” – the ratio of kilometers driven in electric power compared to total mileage. The team determined that just 27% of travel was completed in EV mode, whereas lab estimates assumed over four-fifths.

Even, when operating in EV mode, pollution levels were significantly higher than official estimates. That occurred because EV motors were insufficiently powerful enough to function alone, leading to engines using gasoline for almost one-third of the travel covered in EV mode.

Regulatory and Financial Implications

Based on calculations, the lowballing of PHEV emissions allowed four major automaker groups to escape more than €5bn in fines between 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs would spend about €500 more per year in operating costs than is assumed under laboratory tests.

“The strong statements that automakers often promote about their plug-in hybrid vehicles are clearly way off the mark,” stated a automotive analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. Actually, PHEVs are only slightly better than regular gas and diesel cars in terms of energy use, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Pressure

Hybrid vehicles have lately been brought back into political discussions as automakers have lobbied the EU to relax CO₂ targets. A planned prohibition on new combustion engine cars in 2035 has faced heavy pressure from the car sector and resistance from member states with large automotive manufacturing.

Several high-level politicians have suggested PHEVs as a potential “flexibility” option to introduce in the regulation.

An external energy economics expert, who was not involved with the research, called the report a “very useful contribution” after years in which segments of the car industry claimed there was insufficient data to properly evaluate actual emissions.

“The results show, beyond any doubt, that the gap in official and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or diesel vehicles,” they said. “Any regulatory adjustments regarding PHEVs should be implemented with utmost caution and considering that evidence.”