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PHEVs release nearly 5x greater planet-heating emissions than official data indicate, as per a recent analysis.

Growing Gap In Lab and Real-World Emissions

Data reveals that PHEVs emit just one-fifth lower CO₂ than conventional petrol and diesel cars, according to analysis conducted by a non-profit organization. This differs sharply with laboratory tests, which suggested a 75% reduction in pollution.

Researchers studied information from onboard fuel consumption monitors of 800,000 vehicles sold in Europe between 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab figures, up from 3.5 times in 2021.

“Actual emissions are rising, while lab-reported figures are decreasing,” said a lead analyst participating in the study. “This gap is growing and poses a significant problem. Consequently, PHEVs pollute nearly as much as petrol cars.”

Key Reasons Behind the Emissions Gap

Researchers linked the majority of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers driven in electric power compared to total distance. They found that only 27% of driving was completed in EV mode, whereas official estimates assumed over four-fifths.

Additionally, when operating in EV mode, pollution levels were well above official estimates. That occurred because EV motors were not strong enough to operate independently, resulting to engines using fossil fuels for nearly one-third of the travel covered in EV mode.

Policy and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output enabled four large carmaker companies to avoid more than €5bn in fines between 2021 and 2023, by falsely simplifying adherence with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs would spend approximately €500 more annually in operating costs than would be assumed under laboratory tests.

“The bold claims that automakers like to make about their PHEV cars are obviously way off the mark,” commented a transport expert. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are little better than standard petrol and diesel cars in terms of fuel use, CO₂ emissions, and running expenses.”

Policy Discussion and Automotive Pressure

Plug-in hybrid cars have lately been drawn again into political discussions as carmakers have lobbied the European Union to relax CO₂ targets. A planned ban on sales of new internal combustion cars in 2035 has faced intense pressure from the automotive industry and resistance from EU countries with large car industries.

Some high-level officials have suggested PHEVs as a potential “flexibility” solution to introduce in the regulation.

An independent energy policy specialist, who was unaffiliated with the study, called the report a “very useful addition” after a long period in which segments of the automotive industry argued there was too little data to properly assess actual emissions.

“The results demonstrate, without question, that the gap in lab and actual PHEV energy use and CO₂ output is much, much greater than for petrol or conventional cars,” the expert said. “Any regulatory changes concerning PHEVs should be made with extreme care and in the light of that evidence.”