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Plug-in hybrid electric vehicles produce almost 5x greater planet-heating emissions than lab-reported data indicate, as per a recent analysis.

Widening Gap In Lab and Actual CO2 Output

Statistics shows that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel vehicles, based on research carried out by a advocacy group. This differs significantly with laboratory tests, which suggested a 75% reduction in pollution.

Researchers examined information from onboard energy use monitors of 800,000 vehicles sold in the EU from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, up from 3.5 times in 2021.

“Actual emissions are rising, while official emissions are decreasing,” said a lead researcher involved in the study. “This discrepancy is widening and creates a significant issue. As a result, PHEVs pollute almost as heavily as petrol vehicles.”

Primary Factors Driving the Emissions Gap

Researchers attributed most of the difference to overestimates of the “utility factor” – the percentage of miles driven in electric power compared to overall mileage. They determined that just a quarter of driving was done in EV mode, whereas official assumptions assumed 84%.

Even, when running in electric mode, emission amounts were well above official estimates. That occurred because electric motors were insufficiently powerful enough to operate independently, resulting to engines using gasoline for nearly a third of the distance covered in electric mode.

Regulatory and Economic Implications

According to calculations, the lowballing of PHEV emissions enabled several large automaker groups to avoid over €5bn in fines between 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs could spend approximately €500 extra annually in operating expenses than is estimated under laboratory tests.

“The strong claims that manufacturers like to make about their PHEV vehicles are obviously far from the truth,” stated a transport expert. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and saving costs. Actually, PHEVs are only slightly improved than regular gas and diesel cars in terms of energy use, CO₂ emissions, and running expenses.”

Political Discussion and Industry Pressure

Hybrid cars have recently been drawn back into political debates as automakers have pressed the EU to relax CO₂ standards. A planned ban on sales of new combustion engine vehicles in 2035 has faced heavy lobbying from the car industry and opposition from EU countries with large car industries.

Several senior politicians have proposed PHEVs as a possible “compromise” solution to introduce in the legislation.

One independent energy policy expert, who was not involved with the research, called the analysis a “highly valuable contribution” after a long period in which segments of the automotive sector claimed there was insufficient information to properly evaluate real-world emissions.

“These findings demonstrate, without question, that the gap between lab and actual PHEV fuel consumption and CO₂ output is significantly greater than for petrol or conventional cars,” they stated. “Any regulatory changes concerning PHEVs should be made with utmost caution and in the light of that evidence.”