🔗 Share this article

PHEVs release almost 5x more planet-heating pollution than official data indicate, as per a recent analysis.

Growing Discrepancy In Lab and Real-World CO2 Output

Data shows that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel vehicles, according to research carried out by a non-profit group. That differs significantly with lab tests, which suggested a three-quarters decrease in emissions.

Researchers examined information from in-vehicle fuel consumption monitors of eight hundred thousand cars registered in the EU from 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than official figures, up from 3.5 times in 2021.

“Real-world CO2 output are rising, while lab-reported emissions are falling,” said a senior analyst participating in the study. “That discrepancy is widening and creates a serious issue. As a result, PHEVs pollute almost as heavily as gasoline vehicles.”

Primary Reasons Behind the Emissions Gap

Researchers attributed the majority of the difference to inflated estimates of the “electric driving share” – the percentage of miles travelled in electric mode compared to overall distance. They found that only a quarter of driving was completed in electric mode, while lab estimates suggested over four-fifths.

Additionally, when operating in EV mode, pollution levels were significantly higher than lab estimates. This happened because EV motors were not strong enough to function independently, leading to engines using fossil fuels for nearly one-third of the travel covered in electric mode.

Policy and Economic Implications

Based on estimates, the lowballing of PHEV emissions enabled four large automaker companies to escape more than €5bn in fines between 2021 and 2023, by falsely simplifying adherence with EU average fleet CO₂ standards.

Additionally, owners of PHEVs would pay about €500 more per year in operating expenses than would be estimated under laboratory conditions.

“The bold claims that manufacturers often promote about their PHEV cars are clearly far from the mark,” stated a transport analyst. “Buyers are being duped into believing that by buying a PHEV, they are helping the environment and saving money. In reality, PHEVs are only slightly improved than standard petrol and diesel cars in terms of fuel consumption, CO₂ production, and running expenses.”

Political Discussion and Automotive Pressure

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

Several senior politicians have suggested plug-in hybrids as a possible “compromise” solution to include in the legislation.

One external energy economics expert, who was not involved with the research, called the report a “very useful contribution” after years in which parts of the automotive sector argued there was insufficient data to properly evaluate actual emissions.

“The results demonstrate, beyond any doubt, that the difference between official and real-world PHEV energy use and CO₂ emissions is much, much larger than for petrol or conventional cars,” they stated. “Any regulatory changes regarding PHEVs should be implemented with utmost caution and considering that data.”