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PHEVs produce nearly 5x more global warming pollution than official figures show, according to a recent report.

Growing Discrepancy Between Lab and Real-World Emissions

Statistics shows that PHEVs release only one-fifth less CO₂ than traditional gas and diesel vehicles, based on research carried out by a advocacy organization. This contrasts sharply with laboratory tests, which suggested a three-quarters decrease in pollution.

Analysts studied information from onboard fuel consumption meters of eight hundred thousand cars registered in the EU from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while lab-reported figures are falling,” said a senior researcher participating in the study. “This discrepancy is growing and creates a serious problem. Consequently, PHEVs emit almost as heavily as petrol vehicles.”

Primary Reasons Behind the Discrepancy

Researchers linked most of the gap to inflated estimates of the “utility factor” – the ratio of kilometers driven in electric mode relative to overall distance. The team determined that just 27% of travel was done in EV mode, whereas lab assumptions suggested 84%.

Additionally, when operating in EV mode, pollution amounts were well above lab estimates. That occurred because EV motors were not strong enough to operate alone, leading to combustion motors using gasoline for nearly a third of the travel completed in EV mode.

Policy and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output enabled four major automaker groups to escape more than €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs could pay about €500 more annually in operating costs than would be estimated under lab tests.

“The bold statements that automakers like to make about their PHEV vehicles are clearly way off the truth,” commented a automotive expert. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are little better than regular gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and running expenses.”

Policy Debate and Industry Lobbying

Hybrid vehicles have recently been drawn again into policy discussions as automakers have pressed the European Union to relax CO₂ targets. A planned prohibition on sales of new combustion engine vehicles in 2035 has faced heavy lobbying from the car sector and resistance from EU countries with significant automotive manufacturing.

Some senior politicians have proposed PHEVs as a possible “flexibility” option to introduce in the regulation.

One external energy economics specialist, who was not involved with the research, called the analysis a “highly valuable contribution” after a long period in which segments of the car sector argued there was too little information to accurately assess real-world emissions.

“The results demonstrate, beyond any doubt, that the gap in official and actual PHEV energy use and CO₂ emissions is much, much larger than for petrol or conventional vehicles,” they said. “All policy changes concerning PHEVs should be implemented with extreme caution and in the light of that data.”