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Plug-in hybrid cars release nearly five times more planet-heating emissions than lab-reported figures show, as per a recent report.

Growing Discrepancy In Official and Real-World CO2 Output

Data shows that PHEVs emit just 19% less CO₂ than conventional gas and diesel cars, according to research carried out by a advocacy group. This differs significantly with lab estimates, which assumed a three-quarters decrease in pollution.

Researchers studied information from in-vehicle energy use meters of 800,000 vehicles sold in Europe between 2021 and 2023. The team 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.

“Actual CO2 output are rising, while lab-reported emissions are falling,” stated a senior analyst involved in the report. “That discrepancy is widening and poses a serious problem. As a result, PHEVs emit almost as much as petrol cars.”

Key Reasons Driving the Emissions Gap

Researchers linked most of the difference to overestimates of the “utility factor” – the percentage of miles driven in electric power compared to total mileage. The team found that only a quarter of travel was completed in EV mode, whereas official estimates suggested over four-fifths.

Additionally, when running in EV mode, pollution amounts were well above lab projections. That happened because EV motors were not strong enough to operate independently, leading to combustion motors burning fossil fuels for almost a third of the distance completed in electric mode.

Policy and Economic Implications

According to calculations, the underestimation of PHEV CO2 output enabled four major automaker groups to escape more than €5bn in fines from 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs would spend about €500 extra per year in operating costs than is estimated under lab tests.

“The bold claims that automakers like to make about their plug-in hybrid cars are obviously way off the truth,” stated a transport expert. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the planet and cutting money. Actually, PHEVs are only slightly better than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and operating costs.”

Political Discussion and Automotive Lobbying

Plug-in hybrid cars have lately been drawn again into political debates as automakers have lobbied the EU to relax CO₂ targets. A proposed ban on sales of new internal combustion vehicles in 2035 has faced intense pressure from the car sector and resistance from EU countries with significant car industries.

Some senior politicians have proposed plug-in hybrids as a possible “compromise” option to introduce in the regulation.

An external energy policy expert, who was unaffiliated with the study, described the report a “highly valuable contribution” after years in which parts of the automotive industry claimed there was insufficient information to properly assess actual CO2 output.

“The results demonstrate, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ output is significantly greater than for petrol or conventional cars,” they stated. “Any regulatory changes concerning PHEVs should be implemented with utmost care and considering that evidence.”