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Plug-in hybrid electric vehicles emit nearly five times more planet-heating emissions than lab-reported data indicate, as per a recent analysis.

Widening Discrepancy In Lab and Actual Emissions

Statistics reveals that PHEVs emit just 19% less CO₂ than traditional gas and diesel vehicles, according to research conducted by a advocacy group. This contrasts sharply with laboratory tests, which suggested a three-quarters reduction in pollution.

Analysts examined data from onboard fuel consumption monitors of eight hundred thousand cars sold in Europe between 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, increased from three and a half times in 2021.

“Actual emissions are rising, while official figures are decreasing,” said a lead analyst participating in the report. “This gap is growing and poses a significant issue. Consequently, PHEVs pollute nearly as heavily as petrol vehicles.”

Primary Factors Driving the Discrepancy

Researchers attributed the majority of the gap to inflated estimates of the “electric driving share” – the ratio of kilometers driven in electric power compared to overall distance. They found that just 27% of travel was done in EV mode, whereas lab estimates assumed 84%.

Additionally, when running in electric mode, emission levels were well above lab estimates. That occurred because EV motors were not strong sufficient to function alone, resulting to combustion motors burning gasoline for nearly a third of the travel covered in electric mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV emissions allowed several major carmaker groups to escape more than €5bn in fines from 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 extra per year in running expenses than would be assumed under laboratory conditions.

“The strong claims that manufacturers often promote about their PHEV cars are clearly way off the truth,” stated a transport analyst. “Buyers are being misled into believing that by buying a PHEV, they are helping the environment and saving costs. In reality, PHEVs are little better than standard petrol and diesel vehicles in terms of energy consumption, CO₂ production, and running costs.”

Policy Debate and Automotive Pressure

Hybrid vehicles have lately been brought back into policy debates as automakers have lobbied the EU to weaken CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced heavy lobbying from the automotive sector and resistance from member states with large car manufacturing.

Some high-level politicians have suggested PHEVs as a possible “flexibility” solution to introduce in the legislation.

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 car industry claimed there was insufficient data to properly assess actual emissions.

“These findings show, without question, that the gap in lab and real-world PHEV energy use and CO₂ output is much, much greater than for petrol or conventional vehicles,” they said. “Any policy changes concerning PHEVs should be made with utmost care and considering this data.”