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PHEVs release nearly five times greater global warming pollution than official figures show, as per a recent analysis.

Growing Gap Between Official and Real-World CO2 Output

Data shows that PHEVs release just 19% lower CO₂ than conventional petrol and diesel vehicles, based on analysis conducted by a advocacy organization. This contrasts significantly with lab tests, which assumed a three-quarters decrease in emissions.

Researchers studied information from in-vehicle energy use meters of eight hundred thousand cars sold in Europe from 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official figures, increased from three and a half times in 2021.

“Real-world CO2 output are increasing, while official emissions are decreasing,” said a lead analyst involved in the report. “That discrepancy is growing and creates a serious problem. As a result, PHEVs pollute nearly as much as petrol cars.”

Key Reasons Driving the Discrepancy

Researchers linked most of the difference to overestimates of the “utility factor” – the percentage of miles driven in battery mode relative to overall distance. They determined that only 27% of driving was completed in electric mode, while official estimates assumed 84%.

Additionally, when running in electric mode, pollution amounts were well above lab estimates. That happened because EV motors were not strong sufficient to function independently, leading to engines using fossil fuels for nearly a third of the travel covered in electric mode.

Regulatory and Economic Implications

According to calculations, the lowballing of PHEV emissions enabled several large automaker groups to escape over €5bn in fines from 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs could pay approximately €500 more per year in running costs than is estimated under lab conditions.

“The bold claims that automakers like to make about their PHEV cars are obviously way off the truth,” stated a automotive expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the environment and cutting money. Actually, PHEVs are little improved than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and running costs.”

Policy Debate and Automotive Pressure

Plug-in hybrid vehicles have lately been brought back into political debates as automakers have lobbied the European Union to weaken CO₂ targets. A proposed prohibition on new internal combustion cars in 2035 has faced intense pressure from the car sector and opposition from EU countries with significant automotive industries.

Several high-level officials have suggested PHEVs as a possible “flexibility” option to introduce in the legislation.

An independent energy policy specialist, who was not involved with the research, called the report a “highly valuable contribution” after a long period in which segments of the automotive sector argued there was too little data to accurately assess actual CO2 output.

“These findings show, beyond any doubt, that the gap in official and real-world PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or diesel cars,” the expert stated. “All policy changes regarding PHEVs should be implemented with utmost care and considering that data.”