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Plug-in hybrid electric vehicles emit almost five times greater planet-heating pollution than lab-reported data indicate, as per a recent analysis.

Widening Discrepancy In Lab and Real-World CO2 Output

Statistics reveals that PHEVs release just 19% less CO₂ than conventional petrol and diesel vehicles, according to research carried out by a advocacy organization. This contrasts sharply with lab tests, which suggested a 75% decrease in emissions.

Researchers studied information from onboard energy use meters of eight hundred thousand vehicles sold in Europe from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, up from three and a half times in 2021.

“Real-world emissions are increasing, while official figures are decreasing,” stated a lead analyst participating in the report. “That gap is growing and poses a serious problem. Consequently, PHEVs pollute almost as much as gasoline vehicles.”

Key Factors Driving the Discrepancy

Analysts attributed the majority of the difference to overestimates of the “utility factor” – the percentage of miles driven in battery mode compared to total mileage. The team determined that just a quarter of driving was done in electric mode, whereas lab estimates assumed 84%.

Even, when operating in electric mode, emission amounts were significantly higher than official estimates. This occurred because electric motors were not strong sufficient to function independently, resulting to combustion motors using fossil fuels for nearly one-third of the travel completed in electric mode.

Regulatory and Economic Consequences

According to estimates, the underestimation of PHEV emissions enabled several large automaker groups to escape over €5bn in penalties between 2021 and 2023, by artificially easing compliance with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs would spend about €500 extra annually in running costs than would be estimated under laboratory conditions.

“The strong statements that automakers like to make about their plug-in hybrid cars are obviously way off the mark,” commented a automotive analyst. “Consumers are being misled into thinking that by purchasing a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little better than regular petrol and diesel cars in terms of energy consumption, CO₂ emissions, and running costs.”

Political Debate and Industry Lobbying

Plug-in hybrid cars have lately been drawn again into political debates as automakers have lobbied the EU to weaken CO₂ targets. A proposed prohibition on sales of new internal combustion vehicles in 2035 has faced intense lobbying from the car industry and resistance from EU countries with large car manufacturing.

Several senior officials have suggested plug-in hybrids as a possible “compromise” option to include in the legislation.

An external energy policy expert, who was not involved with the study, called the analysis a “very useful contribution” after years in which parts of the car industry argued there was too little information to properly assess actual emissions.

“The results demonstrate, without question, that the gap in lab and real-world PHEV energy use and CO₂ emissions is significantly larger than for petrol or conventional vehicles,” they said. “All policy adjustments concerning PHEVs should be implemented with utmost caution and considering this data.”