Plug-in Hybrid electric Cars Pollute Nearly as Much as Gasoline Vehicles, Report Finds

Plug-in hybrid electric vehicles emit nearly five times more planet-heating pollution than lab-reported figures indicate, as per a recent report.

Widening Gap Between Lab and Actual CO2 Output

Data reveals that PHEVs emit only 19% lower CO₂ than conventional petrol and diesel cars, based on research carried out by a advocacy organization. This differs significantly with laboratory estimates, which assumed a three-quarters reduction in pollution.

Researchers studied data from in-vehicle fuel consumption monitors of 800,000 vehicles registered in the EU from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, up from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are decreasing,” stated a senior researcher participating in the study. “This gap is growing and creates a serious issue. As a result, PHEVs emit nearly as much as gasoline vehicles.”

Key Factors Behind the Emissions Gap

Researchers linked most of the difference to inflated estimates of the “electric driving share” – the ratio of miles driven in electric mode compared to overall mileage. They determined that just a quarter of travel was completed in electric mode, while lab estimates suggested over four-fifths.

Additionally, when running in EV mode, emission levels were significantly higher than official projections. That happened because EV motors were not strong enough to function alone, leading to combustion motors using fossil fuels for nearly a third of the distance completed in electric mode.

Regulatory and Economic Consequences

Based on calculations, the lowballing of PHEV CO2 output enabled several large carmaker companies to avoid more than €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ targets.

Additionally, owners of PHEVs could pay approximately €500 more annually in operating costs than would be assumed under laboratory tests.

“The strong claims that manufacturers like to make about their plug-in hybrid vehicles are obviously far from the mark,” commented a automotive expert. “Buyers are being duped into believing that by purchasing a PHEV, they are helping the environment and saving costs. In reality, PHEVs are little improved than regular gas and diesel cars in terms of fuel use, CO₂ production, and operating expenses.”

Political Debate and Industry Lobbying

Hybrid cars have recently been brought again into political discussions as automakers have lobbied the EU to relax CO₂ targets. A planned prohibition on new internal combustion cars in 2035 has faced intense lobbying from the car sector and resistance from EU countries with significant automotive manufacturing.

Some high-level politicians have suggested plug-in hybrids as a possible “flexibility” solution to introduce in the legislation.

One external energy economics expert, who was unaffiliated with the research, called the report a “very useful addition” after years in which segments of the car sector argued there was insufficient information to properly evaluate real-world emissions.

“These findings show, without question, that the difference in lab and real-world PHEV fuel consumption and CO₂ emissions is significantly larger than for gasoline or diesel cars,” the expert said. “All policy adjustments concerning PHEVs should be made with extreme care and in the light of this data.”