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Plug-in hybrid cars release nearly five times greater planet-heating emissions than official data show, as per a recent report.

Widening Gap In Lab and Real-World CO2 Output

Data shows that PHEVs release just one-fifth lower CO₂ than conventional petrol and diesel vehicles, based on analysis conducted by a advocacy organization. This contrasts significantly with lab estimates, which assumed a 75% decrease in pollution.

Researchers examined data from in-vehicle energy use monitors of 800,000 vehicles sold in Europe between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, up from 3.5 times in 2021.

“Real-world CO2 output are rising, while official emissions are decreasing,” said a lead analyst involved in the study. “This gap is growing and creates a significant problem. As a result, PHEVs pollute nearly as heavily as petrol vehicles.”

Primary Reasons Driving the Discrepancy

Analysts attributed most of the gap to inflated estimates of the “utility factor” – the ratio of miles travelled in battery power compared to total distance. They determined that just 27% of driving was done in EV mode, whereas official estimates suggested over four-fifths.

Additionally, when operating in electric mode, emission levels were significantly higher than official estimates. This happened because EV motors were insufficiently powerful sufficient to operate alone, resulting to engines burning fossil fuels for nearly one-third of the travel covered in EV mode.

Regulatory and Economic Implications

According to estimates, the underestimation of PHEV CO2 output enabled several major automaker companies to avoid over €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ standards.

Additionally, owners of PHEVs could pay approximately €500 more per year in running costs than is assumed under laboratory tests.

“The bold statements that automakers often promote about their plug-in hybrid cars are obviously way off the mark,” commented a automotive expert. “Buyers are being duped into thinking that by purchasing a PHEV, they are helping the planet and saving costs. In reality, PHEVs are little improved than standard petrol and diesel cars in terms of energy use, CO₂ production, and operating expenses.”

Policy Discussion and Automotive Lobbying

Hybrid vehicles have recently been brought again into policy debates as automakers have pressed the European Union to relax CO₂ standards. A planned ban on new internal combustion vehicles in 2035 has faced intense pressure from the car sector and resistance from member states with large car industries.

Some senior politicians have proposed PHEVs as a potential “flexibility” option to include in the legislation.

One independent energy policy expert, who was not involved with the study, called the report a “highly valuable contribution” after a long period in which parts of the car sector claimed there was insufficient data to properly evaluate real-world CO2 output.

“These findings demonstrate, without question, that the difference in official and real-world PHEV energy use and CO₂ emissions is significantly greater than for petrol or diesel cars,” the expert said. “All policy adjustments concerning PHEVs should be implemented with utmost caution and in the light of this evidence.”