🔗 Share this article

PHEVs produce almost 5x more planet-heating pollution than lab-reported data indicate, according to a new report.

Growing Discrepancy Between Official and Real-World Emissions

Data reveals that PHEVs release only 19% lower CO₂ than conventional gas and diesel vehicles, based on analysis conducted by a non-profit organization. That differs significantly with lab estimates, which suggested a three-quarters decrease in pollution.

Researchers studied data from in-vehicle fuel consumption monitors of 800,000 vehicles sold in Europe between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are decreasing,” said a lead researcher involved in the study. “This gap is widening and poses a significant problem. As a result, PHEVs pollute almost as much as petrol cars.”

Key Reasons Behind the Discrepancy

Analysts linked the majority of the difference to overestimates of the “utility factor” – the percentage of miles driven in electric power relative to total distance. The team determined that only a quarter of driving was done in EV mode, while official estimates assumed 84%.

Additionally, when operating in EV mode, pollution levels were significantly higher than official estimates. That happened because electric motors were not strong enough to operate alone, leading to engines burning gasoline for almost one-third of the distance covered in EV mode.

Regulatory and Financial Consequences

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

Additionally, owners of PHEVs would pay approximately €500 more annually in running costs than is estimated under laboratory tests.

“The bold statements that manufacturers like to make about their PHEV vehicles are clearly way off the mark,” stated a automotive expert. “Buyers are being duped into believing that by buying a PHEV, they are benefiting the planet and saving money. In reality, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of energy consumption, CO₂ production, and operating expenses.”

Policy Discussion and Automotive Lobbying

Hybrid cars have lately been drawn back into political debates as automakers have pressed the European Union to relax CO₂ standards. A proposed ban on sales of new combustion engine cars in 2035 has faced intense pressure from the car sector and opposition from EU countries with significant automotive manufacturing.

Several senior officials have proposed plug-in hybrids as a possible “flexibility” option to include in the regulation.

One external energy policy expert, who was unaffiliated with the study, called the report a “highly valuable addition” after a long period in which segments of the car industry claimed there was too little information to properly evaluate real-world emissions.

“These findings demonstrate, without question, that the gap in lab and actual PHEV energy use and CO₂ output is much, much larger than for gasoline or conventional cars,” they said. “Any regulatory adjustments regarding PHEVs should be implemented with extreme care and in the light of this evidence.”