🔗 Share this article

Plug-in hybrid cars produce nearly five times greater global warming pollution than official data indicate, according to a new report.

Widening Discrepancy In Official and Real-World CO2 Output

Statistics reveals that PHEVs emit only 19% less CO₂ than traditional petrol and diesel vehicles, based on research carried out by a non-profit group. That contrasts sharply with lab tests, which assumed a 75% reduction in pollution.

Analysts examined information from in-vehicle fuel consumption meters of 800,000 cars sold in Europe from 2021 and 2023. They discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than official estimates, increased from 3.5 times in 2021.

“Actual emissions are increasing, while official figures are decreasing,” stated a lead analyst participating in the study. “This discrepancy is growing and poses a serious issue. Consequently, PHEVs emit almost as heavily as gasoline vehicles.”

Primary Reasons Driving the Discrepancy

Researchers attributed most of the gap to overestimates of the “utility factor” – the ratio of kilometers travelled in battery mode compared to total mileage. They found that just a quarter of travel was completed in EV mode, while lab estimates suggested 84%.

Additionally, when operating in electric mode, pollution levels were significantly higher than lab estimates. That happened because EV motors were insufficiently powerful enough to function independently, leading to combustion motors using fossil fuels for almost a third of the travel completed in EV mode.

Regulatory and Economic Consequences

According to calculations, the lowballing of PHEV CO2 output allowed several large automaker groups to escape over €5bn in fines between 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs could spend about €500 more per year in running expenses than is assumed under laboratory tests.

“The strong claims that manufacturers like to make about their PHEV cars are clearly far from the mark,” stated a transport analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and saving money. In reality, PHEVs are little improved than standard petrol and diesel cars in terms of fuel use, CO₂ production, and running expenses.”

Policy Discussion and Automotive Pressure

Plug-in hybrid vehicles have recently been drawn again into political discussions as automakers have pressed the EU to relax CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense lobbying from the car sector and resistance from EU countries with significant automotive industries.

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

An external energy economics expert, who was not involved with the study, described the report a “highly valuable addition” after a long period in which parts of the car sector claimed there was too little information to properly evaluate real-world emissions.

“These findings show, without question, that the gap in lab and actual PHEV fuel consumption and CO₂ output is much, much greater than for petrol or diesel vehicles,” the expert stated. “All policy adjustments regarding PHEVs should be implemented with utmost caution and in the light of that data.”