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

PHEVs release nearly five times greater global warming emissions than lab-reported figures indicate, as per a recent report.

Widening Gap In Lab and Real-World Emissions

Data reveals that PHEVs emit just one-fifth less CO₂ than traditional gas and diesel vehicles, according to research conducted by a advocacy group. That differs sharply with laboratory estimates, which assumed a three-quarters decrease in pollution.

Analysts examined information from in-vehicle fuel consumption meters of eight hundred thousand cars sold in Europe from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than lab estimates, increased from three and a half times in 2021.

“Real-world CO2 output are rising, while lab-reported figures are decreasing,” said a senior researcher participating in the study. “That gap is growing and poses a serious issue. As a result, PHEVs pollute almost as much as petrol cars.”

Primary Factors Behind the Discrepancy

Analysts linked the majority of the difference to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric power compared to total distance. The team determined that just a quarter of driving was done in electric mode, whereas lab assumptions assumed over four-fifths.

Additionally, when running in electric mode, pollution levels were well above lab estimates. This occurred because electric motors were insufficiently powerful enough to function independently, leading to engines burning fossil fuels for nearly a third of the travel covered in EV mode.

Regulatory and Economic Implications

Based on calculations, the lowballing of PHEV CO2 output enabled several large carmaker companies to avoid over €5bn in fines between 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs could pay approximately €500 extra per year in operating expenses than is estimated under laboratory tests.

“The bold statements that manufacturers like to make about their PHEV cars are obviously way off the truth,” commented a automotive analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are helping the environment and saving costs. In reality, PHEVs are little improved than standard gas and diesel cars in terms of energy use, CO₂ emissions, and operating expenses.”

Political Debate and Industry Pressure

Hybrid vehicles have recently been drawn again into political debates as carmakers have pressed the EU to weaken CO₂ standards. A proposed ban on new internal combustion vehicles in 2035 has faced heavy pressure from the automotive sector and resistance from EU countries with large car industries.

Some high-level officials have suggested plug-in hybrids as a potential “flexibility” solution to introduce in the regulation.

An independent energy policy specialist, who was not involved with the research, called the analysis a “highly valuable addition” after a long period in which parts of the car industry argued there was insufficient information to accurately assess real-world emissions.

“The results show, beyond any doubt, that the difference in lab and real-world PHEV energy use and CO₂ output is much, much larger than for petrol or diesel vehicles,” the expert stated. “Any policy changes concerning PHEVs should be made with extreme caution and in the light of that evidence.”