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Plug-in hybrid cars emit nearly 5x greater global warming emissions than lab-reported figures show, as per a recent analysis.

Growing Gap In Official and Real-World CO2 Output

Statistics shows that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel vehicles, based on research conducted by a advocacy organization. That differs sharply with lab estimates, which suggested a three-quarters decrease in pollution.

Analysts studied data from in-vehicle energy use meters of 800,000 vehicles registered in the EU between 2021 and 2023. The team discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, increased from 3.5 times in 2021.

“Real-world emissions are increasing, while official emissions are falling,” stated a senior researcher participating in the study. “That gap is growing and poses a significant problem. Consequently, PHEVs pollute nearly as heavily as gasoline cars.”

Primary Factors Driving the Discrepancy

Researchers linked most of the gap to overestimates of the “electric driving share” – the percentage of kilometers driven in electric power relative to overall distance. They determined that just 27% of travel was completed in EV mode, whereas lab assumptions assumed 84%.

Even, when operating in EV mode, emission levels were well above lab estimates. That occurred because electric motors were not strong sufficient to operate alone, resulting to engines using gasoline for nearly one-third of the travel covered in electric mode.

Policy and Financial Implications

According to calculations, the lowballing of PHEV emissions allowed four large automaker companies to avoid more than €5bn in fines between 2021 and 2023, by artificially easing adherence with EU fleet-average CO₂ targets.

Additionally, owners of PHEVs would spend approximately €500 extra per year in running costs than is assumed under laboratory conditions.

“The bold statements that automakers like to make about their PHEV vehicles are clearly way off the mark,” commented a transport expert. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are only slightly better than standard gas and diesel cars in terms of energy use, CO₂ emissions, and running expenses.”

Policy Discussion and Industry Lobbying

Hybrid vehicles have recently been drawn again into political discussions as automakers have lobbied the European Union to relax CO₂ targets. A planned ban on sales of new internal combustion vehicles in 2035 has faced intense pressure from the automotive sector and opposition from EU countries with significant automotive manufacturing.

Several senior politicians have suggested PHEVs as a possible “flexibility” solution to include in the legislation.

An independent energy economics specialist, who was not involved with the research, called the report a “very useful contribution” after a long period in which segments of the automotive sector claimed there was too little information to accurately evaluate real-world CO2 output.

“The results demonstrate, beyond any doubt, that the difference in lab and real-world PHEV energy use and CO₂ emissions is significantly larger than for petrol or conventional vehicles,” the expert said. “All policy adjustments concerning PHEVs should be implemented with extreme caution and in the light of this evidence.”