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

Widening Discrepancy In Lab and Actual CO2 Output

Data shows that PHEVs release just 19% less CO₂ than traditional gas and diesel cars, according to analysis carried out by a advocacy group. This contrasts significantly with laboratory tests, which assumed a three-quarters reduction in pollution.

Analysts studied data from in-vehicle energy use meters of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official figures, up from 3.5 times in 2021.

“Actual CO2 output are increasing, while official emissions are falling,” said a lead analyst involved in the report. “That gap is widening and creates a significant issue. As a result, PHEVs emit nearly as much as petrol vehicles.”

Primary Factors Behind the Emissions Gap

Researchers linked the majority of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in battery power relative to overall distance. The team found that only a quarter of travel was completed in electric mode, while lab assumptions suggested over four-fifths.

Even, when operating in electric mode, emission amounts were well above lab projections. This happened because electric motors were insufficiently powerful enough to operate alone, leading to engines burning gasoline for nearly a third of the travel covered in EV mode.

Regulatory and Financial Implications

According to calculations, the lowballing of PHEV emissions allowed four major automaker groups to avoid more than €5bn in fines from 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ targets.

Furthermore, drivers of PHEVs would pay about €500 more annually in running expenses than is estimated under laboratory conditions.

“The strong claims that automakers often promote about their PHEV vehicles are obviously way off the mark,” stated a automotive expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and cutting costs. Actually, PHEVs are little better than standard gas and diesel cars in terms of energy consumption, CO₂ emissions, and operating expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid cars have lately been drawn back into policy discussions as automakers have lobbied the EU to relax CO₂ targets. A proposed ban on new internal combustion vehicles in 2035 has faced heavy pressure from the car industry and resistance from EU countries with significant car manufacturing.

Several senior politicians have proposed plug-in hybrids as a potential “flexibility” option to introduce in the legislation.

An independent energy economics specialist, who was unaffiliated with the study, described the analysis a “highly valuable contribution” after years in which parts of the car industry claimed there was insufficient information to properly evaluate actual CO2 output.

“The results show, beyond any doubt, that the gap in official and real-world PHEV energy use and CO₂ output is much, much greater than for gasoline or conventional vehicles,” the expert said. “All regulatory changes concerning PHEVs should be implemented with extreme caution and considering that data.”