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PHEVs release nearly 5x greater global warming pollution than lab-reported data show, as per a recent analysis.

Growing Gap Between Official and Actual Emissions

Data shows that PHEVs emit only one-fifth lower CO₂ than conventional gas and diesel vehicles, based on analysis conducted by a non-profit organization. This contrasts significantly with laboratory tests, which suggested a 75% decrease in pollution.

Researchers examined data from in-vehicle energy use meters of 800,000 cars registered in Europe between 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are decreasing,” said a senior researcher involved in the study. “This discrepancy is growing and poses a significant problem. As a result, PHEVs emit nearly as much as gasoline cars.”

Key Factors Behind the Discrepancy

Researchers linked the majority of the difference to overestimates of the “utility factor” – the ratio of kilometers driven in electric power relative to total distance. They found that only 27% of travel was completed in EV mode, while official assumptions assumed 84%.

Additionally, when running in EV mode, pollution levels were well above lab estimates. This occurred because electric motors were insufficiently powerful enough to function independently, leading to combustion motors burning fossil fuels for almost a third of the travel covered in EV mode.

Regulatory and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output allowed four major automaker groups to escape over €5bn in penalties from 2021 and 2023, by artificially easing compliance with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would pay approximately €500 extra per year in operating expenses than is assumed under laboratory tests.

“The strong statements that automakers often promote about their PHEV cars are obviously way off the truth,” commented a automotive expert. “Consumers are being misled into thinking that by buying a PHEV, they are helping the environment and saving costs. Actually, PHEVs are little better than standard petrol and diesel vehicles in terms of energy use, CO₂ production, and running costs.”

Political Discussion and Industry Pressure

Hybrid cars have recently been brought back into policy debates as automakers have pressed the EU to relax CO₂ targets. A proposed prohibition on new internal combustion cars in 2035 has faced heavy lobbying from the car sector and opposition from member states with significant car manufacturing.

Several high-level politicians have proposed plug-in hybrids as a possible “flexibility” solution to include in the legislation.

One independent energy economics expert, who was unaffiliated with the study, called the report a “very useful addition” after a long period in which parts of the automotive industry claimed there was insufficient information to accurately evaluate real-world emissions.

“These findings show, beyond any doubt, that the difference between official and real-world PHEV energy use and CO₂ emissions is significantly larger than for gasoline or diesel vehicles,” the expert stated. “Any regulatory adjustments regarding PHEVs should be implemented with utmost caution and considering this data.”