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Plug-in hybrid cars emit almost five times more global warming emissions than official figures show, according to a new analysis.

Widening Gap In Lab and Real-World CO2 Output

Statistics reveals that PHEVs release just 19% less CO₂ than conventional petrol and diesel vehicles, based on research carried out by a non-profit organization. That contrasts significantly with laboratory estimates, which assumed a 75% decrease in pollution.

Analysts studied information from in-vehicle energy use monitors of eight hundred thousand vehicles sold in the EU from 2021 and 2023. They discovered that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while official figures are falling,” stated a senior researcher participating in the report. “This gap is growing and creates a significant problem. Consequently, PHEVs emit nearly as much as petrol cars.”

Primary Reasons Driving the Emissions Gap

Analysts linked the majority of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in electric power relative to total distance. They determined that only 27% of driving was completed in electric mode, while official assumptions suggested 84%.

Additionally, when running in electric mode, emission levels were significantly higher than official projections. That occurred because EV motors were not strong enough to function alone, resulting to engines using gasoline for nearly a third of the travel covered in electric mode.

Policy and Economic Consequences

Based on calculations, the lowballing of PHEV emissions allowed four large automaker companies to avoid over €5bn in fines from 2021 and 2023, by falsely easing adherence with EU average fleet CO₂ standards.

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

“The strong statements that automakers often promote about their plug-in hybrid vehicles are clearly far from the truth,” commented a automotive analyst. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the environment and cutting costs. Actually, PHEVs are little better than standard petrol and diesel cars in terms of fuel use, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been brought back into political discussions as carmakers have pressed the European Union to weaken CO₂ targets. A planned ban on new internal combustion vehicles in 2035 has faced heavy pressure from the car industry and resistance from EU countries with large car manufacturing.

Several senior politicians have proposed plug-in hybrids as a potential “flexibility” solution to introduce in the regulation.

One external energy economics specialist, who was not involved with the study, described the analysis a “very useful addition” after years in which segments of the automotive industry claimed there was too little information to accurately assess actual emissions.

“These findings show, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ emissions is significantly greater than for petrol or diesel cars,” they said. “Any policy adjustments regarding PHEVs should be made with utmost care and considering that evidence.”