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Plug-in hybrid electric vehicles emit almost 5x greater global warming emissions than lab-reported data indicate, according to a recent report.

Growing Discrepancy Between Official and Real-World Emissions

Data reveals that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel vehicles, according to research conducted by a advocacy organization. That differs significantly with lab estimates, which assumed a 75% decrease in pollution.

Analysts examined data from in-vehicle energy use monitors of eight hundred thousand vehicles sold in Europe from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, increased from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported figures are falling,” stated a senior researcher involved in the report. “That gap is widening and creates a significant problem. Consequently, PHEVs pollute almost as heavily as gasoline cars.”

Primary Factors Driving the Discrepancy

Analysts linked the majority of the gap to inflated estimates of the “utility factor” – the percentage of miles travelled in electric power compared to overall distance. The team found that just a quarter of driving was done in EV mode, while lab assumptions assumed over four-fifths.

Even, when running in electric mode, emission levels were well above lab estimates. That occurred because EV motors were not strong sufficient to operate independently, leading to combustion motors burning gasoline for almost a third of the distance covered in EV mode.

Policy and Financial Implications

According to calculations, the underestimation of PHEV emissions allowed four large automaker groups to escape over €5bn in penalties from 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ targets.

Furthermore, drivers of PHEVs would spend about €500 more per year in operating costs than would be estimated under laboratory tests.

“The bold statements that manufacturers like to make about their PHEV cars are obviously far from the truth,” commented a automotive expert. “Consumers are being duped into thinking that by buying a PHEV, they are benefiting the planet and cutting money. In reality, PHEVs are little improved than regular gas and diesel vehicles in terms of fuel consumption, CO₂ emissions, and operating costs.”

Political Discussion and Automotive Lobbying

Plug-in hybrid vehicles have lately been drawn back into political discussions as automakers have lobbied the European Union to relax CO₂ standards. A proposed ban on new combustion engine cars in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with large automotive manufacturing.

Some high-level officials have proposed plug-in hybrids as a possible “flexibility” solution to include in the regulation.

An external energy policy expert, who was not involved with the study, described the analysis a “very useful addition” after years in which segments of the car sector argued there was too little data to accurately evaluate actual emissions.

“The results demonstrate, without question, that the difference between lab and actual PHEV energy use and CO₂ emissions is significantly larger than for petrol or diesel cars,” they stated. “Any regulatory adjustments concerning PHEVs should be made with utmost caution and considering that evidence.”