Plug-in Hybrid Vehicles Pollute Almost as Heavily as Petrol Vehicles, Report Reveals

Plug-in hybrid cars emit nearly 5x greater planet-heating pollution than lab-reported figures indicate, as per a new report.

Growing Discrepancy Between Lab and Real-World CO2 Output

Data reveals that PHEVs release only 19% lower CO₂ than traditional gas and diesel vehicles, according to research carried out by a advocacy group. This differs significantly with lab tests, which assumed a three-quarters decrease in emissions.

Analysts studied data from in-vehicle fuel consumption monitors of eight hundred thousand cars sold in Europe from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, up from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported emissions are falling,” stated a lead researcher participating in the study. “That gap is widening and creates a significant problem. As a result, PHEVs pollute almost as much as gasoline cars.”

Key Factors Behind the Emissions Gap

Analysts attributed the majority of the gap to inflated estimates of the “utility factor” – the ratio of miles travelled in electric mode relative to total distance. They determined that just a quarter of driving was done in EV mode, whereas lab estimates suggested over four-fifths.

Even, when running in electric mode, pollution levels were significantly higher than official estimates. That occurred because electric motors were not strong sufficient to function independently, leading to combustion motors burning gasoline for nearly one-third of the travel covered in EV mode.

Regulatory and Financial Consequences

According to calculations, the lowballing of PHEV CO2 output allowed several large automaker companies to escape more than €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ standards.

Furthermore, drivers of PHEVs would pay approximately €500 extra annually in operating costs than is estimated under lab conditions.

“The bold statements that automakers often promote about their plug-in hybrid vehicles are clearly far from the mark,” stated a automotive expert. “Buyers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are only slightly better than regular gas and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Debate and Automotive Pressure

Hybrid cars have recently been drawn back into policy debates as automakers have lobbied the European Union to relax CO₂ targets. A planned ban on new internal combustion cars in 2035 has faced heavy lobbying from the automotive industry and opposition from EU countries with large automotive manufacturing.

Some high-level officials have proposed plug-in hybrids as a possible “compromise” option to introduce in the legislation.

One independent energy policy expert, who was unaffiliated with the research, described the report a “highly valuable contribution” after years in which parts of the car sector argued there was too little data to accurately assess real-world CO2 output.

“These findings show, beyond any doubt, that the difference in official and actual PHEV fuel consumption and CO₂ output is significantly greater than for petrol or diesel cars,” they stated. “Any policy adjustments regarding PHEVs should be implemented with extreme caution and in the light of this data.”