Plug-in Hybrid electric Vehicles Pollute Almost as Much as Petrol Cars, Study Finds

Plug-in hybrid cars produce nearly 5x greater planet-heating emissions than official figures indicate, according to a new analysis.

Growing Gap In Lab and Real-World CO2 Output

Statistics reveals that PHEVs release just 19% lower CO₂ than conventional gas and diesel cars, based on analysis carried out by a non-profit organization. That contrasts significantly with lab tests, which suggested a three-quarters reduction in pollution.

Researchers studied information from onboard fuel consumption meters of eight hundred thousand vehicles registered in the EU from 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported emissions are falling,” stated a lead analyst involved in the report. “This gap is widening and creates a serious problem. Consequently, PHEVs pollute nearly as much as gasoline vehicles.”

Key Reasons Behind the Discrepancy

Analysts attributed the majority of the gap to overestimates of the “utility factor” – the ratio of miles travelled in battery power relative to total mileage. They determined that just a quarter of driving was done in EV mode, whereas official assumptions suggested over four-fifths.

Additionally, when running in electric mode, emission amounts were significantly higher than lab projections. This happened because EV motors were insufficiently powerful sufficient to function independently, leading to combustion motors burning gasoline for nearly one-third of the distance covered in EV mode.

Policy and Financial Implications

According to calculations, the underestimation of PHEV CO2 output enabled four major carmaker companies to avoid over €5bn in penalties from 2021 and 2023, by falsely easing compliance with EU fleet-average CO₂ standards.

Furthermore, drivers of PHEVs would pay about €500 extra annually in running expenses than would be assumed under laboratory conditions.

“The strong statements that automakers like to make about their plug-in hybrid vehicles are clearly far from the truth,” commented a automotive analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are helping the planet and saving money. In reality, PHEVs are little improved than regular gas and diesel cars in terms of energy consumption, CO₂ production, and operating costs.”

Political Debate and Automotive Lobbying

Plug-in hybrid cars have recently been drawn back into political discussions as carmakers have pressed the EU to relax CO₂ standards. A proposed ban on sales of new internal combustion vehicles in 2035 has faced intense pressure from the automotive sector and opposition from EU countries with large car manufacturing.

Some senior politicians have suggested plug-in hybrids as a potential “compromise” solution to include in the regulation.

One independent energy economics expert, who was not involved with the research, described the analysis a “very useful addition” after years in which segments of the car industry argued there was too little information to properly assess actual CO2 output.

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