Plug-in Hybrid Vehicles Emit Nearly as Heavily as Petrol Cars, Study Finds

Plug-in hybrid cars release almost five times more global warming pollution than official figures show, as per a recent analysis.

Widening Gap Between Official and Real-World CO2 Output

Data shows that PHEVs emit only one-fifth less CO₂ than traditional petrol and diesel cars, according to research conducted by a advocacy organization. That differs sharply with lab tests, which suggested a three-quarters decrease in emissions.

Analysts studied information from in-vehicle energy use monitors of 800,000 cars registered in the EU between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official figures, up from three and a half times in 2021.

“Actual emissions are rising, while lab-reported figures are decreasing,” said a lead researcher participating in the study. “This discrepancy is widening and poses a significant issue. As a result, PHEVs pollute nearly as heavily as gasoline vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “utility factor” – the percentage of miles driven in electric power relative to overall distance. The team found that only 27% of driving was completed in electric mode, whereas lab assumptions assumed over four-fifths.

Even, when operating in EV mode, emission levels were significantly higher than official projections. This occurred because EV motors were insufficiently powerful enough to operate independently, resulting to combustion motors using gasoline for almost one-third of the distance covered in EV mode.

Regulatory and Economic Implications

Based on estimates, the underestimation of PHEV CO2 output allowed four major automaker companies to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ standards.

Additionally, drivers of PHEVs could spend approximately €500 more per year in running expenses than would be assumed under lab conditions.

“The bold statements that automakers like to make about their PHEV vehicles are obviously way off the mark,” commented a transport expert. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are little improved than standard gas and diesel vehicles in terms of energy consumption, CO₂ production, and operating expenses.”

Political Discussion and Automotive Lobbying

Plug-in hybrid cars have lately been drawn again into political discussions as automakers have lobbied the European Union to weaken CO₂ targets. A proposed prohibition on new internal combustion vehicles in 2035 has faced intense pressure from the automotive sector and resistance from EU countries with large car industries.

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

One external energy policy specialist, who was not involved with the study, described the analysis a “highly valuable contribution” after a long period in which parts of the automotive sector claimed there was too little information to properly assess actual CO2 output.

“These findings show, without question, that the difference between official and actual PHEV energy use and CO₂ output is much, much larger than for petrol or diesel vehicles,” they stated. “All policy changes concerning PHEVs should be made with utmost care and considering this evidence.”