🔗 Share this article

Plug-in hybrid cars release nearly five times greater global warming pollution than lab-reported figures indicate, according to a recent report.

Growing Discrepancy Between Lab and Actual CO2 Output

Data shows that PHEVs release just one-fifth lower CO₂ than conventional gas and diesel cars, according to research carried out by a non-profit organization. That differs significantly with lab tests, which suggested a three-quarters reduction in pollution.

Analysts examined information from in-vehicle fuel consumption monitors of eight hundred thousand cars sold in the EU between 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official figures, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are decreasing,” stated a lead researcher involved in the report. “That discrepancy is widening and creates a serious problem. As a result, PHEVs emit almost as much as gasoline cars.”

Primary Reasons Behind the Emissions Gap

Researchers linked the majority of the difference to inflated estimates of the “utility factor” – the percentage of miles driven in battery power relative to total distance. They found that only 27% of travel was done in electric mode, whereas official estimates assumed over four-fifths.

Even, when running in electric mode, pollution levels were significantly higher than official estimates. That occurred because EV motors were not strong sufficient to operate independently, leading to engines burning fossil fuels for nearly one-third of the distance covered in electric mode.

Policy and Financial Implications

According to calculations, the underestimation of PHEV emissions allowed four major automaker companies to avoid over €5bn in fines between 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would pay approximately €500 more per year in operating costs than would be estimated under lab tests.

“The bold statements that automakers like to make about their plug-in hybrid vehicles are obviously far from the mark,” stated a transport expert. “Buyers are being misled into believing that by buying a PHEV, they are helping the environment and cutting money. Actually, PHEVs are only slightly improved than standard petrol and diesel cars in terms of energy consumption, CO₂ emissions, and operating expenses.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid vehicles have recently been brought back into political debates as carmakers have lobbied the EU to weaken CO₂ standards. A proposed prohibition on sales of new internal combustion cars in 2035 has faced heavy pressure from the automotive industry and resistance from EU countries with large automotive manufacturing.

Some senior politicians have suggested PHEVs as a possible “compromise” option to include in the regulation.

An external energy economics specialist, who was unaffiliated with the research, described the analysis a “very useful contribution” after years in which segments of the car industry argued there was too little information to accurately assess real-world emissions.

“The results show, beyond any doubt, that the difference between official and actual PHEV fuel consumption and CO₂ output is significantly larger than for petrol or diesel cars,” they stated. “All policy adjustments concerning PHEVs should be made with utmost caution and considering that evidence.”