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PHEVs release almost 5x more planet-heating emissions than lab-reported data indicate, as per a new report.

Widening Gap Between Official and Real-World CO2 Output

Data shows that PHEVs emit only one-fifth lower CO₂ than conventional gas and diesel cars, according to research carried out by a advocacy organization. That differs significantly with lab tests, which suggested a 75% decrease in pollution.

Analysts examined data from in-vehicle fuel consumption meters of 800,000 cars sold in Europe from 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, increased from 3.5 times in 2021.

“Real-world CO2 output are rising, while official figures are decreasing,” stated a lead analyst involved in the study. “This discrepancy is widening and poses a serious issue. As a result, PHEVs emit almost as much as gasoline cars.”

Key Factors Driving the Discrepancy

Researchers linked the majority of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in battery power compared to overall mileage. They found that just a quarter of driving was completed in EV mode, whereas lab estimates assumed over four-fifths.

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

Policy and Economic Implications

Based on estimates, the underestimation of PHEV emissions allowed several major carmaker companies to avoid more than €5bn in penalties between 2021 and 2023, by falsely simplifying adherence with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs would pay approximately €500 more per year in running costs than would be estimated under laboratory conditions.

“The strong claims that automakers like to make about their PHEV vehicles are obviously far from the truth,” stated a transport analyst. “Consumers are being misled into believing that by buying a PHEV, they are benefiting the environment and saving costs. Actually, PHEVs are little better than standard petrol and diesel cars in terms of energy use, CO₂ emissions, and running expenses.”

Political Discussion and Automotive Pressure

Hybrid vehicles have lately been brought again into policy debates as automakers have pressed the European Union to relax CO₂ targets. A planned ban on sales of new combustion engine vehicles in 2035 has faced intense lobbying from the automotive industry and opposition from EU countries with significant automotive industries.

Several high-level politicians have proposed PHEVs as a possible “flexibility” option to include in the legislation.

An independent energy policy specialist, who was not involved with the research, described the analysis a “highly valuable addition” after a long period in which parts of the car sector argued there was too little information to properly assess actual CO2 output.

“The results show, without question, that the gap in lab and real-world PHEV energy use and CO₂ emissions is much, much larger than for petrol or diesel vehicles,” they stated. “All regulatory changes concerning PHEVs should be made with utmost care and in the light of this data.”