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PHEVs produce almost 5x greater global warming emissions than official figures show, according to a recent analysis.

Growing Discrepancy In Official and Actual Emissions

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

Analysts studied information from in-vehicle fuel consumption meters of 800,000 vehicles registered in Europe from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, up from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are decreasing,” said a senior researcher involved in the study. “This discrepancy is widening and creates a significant problem. Consequently, PHEVs pollute nearly as much as gasoline cars.”

Key Reasons Behind the Emissions Gap

Researchers attributed the majority of the difference to overestimates of the “utility factor” – the percentage of kilometers driven in electric mode compared to overall distance. The team found that just 27% of driving was done in electric mode, whereas lab assumptions assumed over four-fifths.

Additionally, when operating in electric mode, emission amounts were well above official projections. That happened because EV motors were not strong sufficient to operate independently, resulting to engines using gasoline for almost a third of the travel completed in EV mode.

Regulatory and Financial Consequences

Based on calculations, the lowballing of PHEV emissions allowed four large carmaker companies to escape more than €5bn in fines from 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ targets.

Additionally, drivers of PHEVs would pay about €500 more per year in operating costs than would be estimated under lab tests.

“The bold statements that manufacturers often promote about their plug-in hybrid cars are obviously far from the mark,” commented a transport analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the planet and cutting money. Actually, PHEVs are only slightly better than standard petrol and diesel cars in terms of energy consumption, CO₂ production, and operating costs.”

Political Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been drawn again into policy debates as carmakers have lobbied the European Union to relax CO₂ targets. A planned ban on sales of new internal combustion vehicles in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with significant car manufacturing.

Several senior politicians have suggested plug-in hybrids as a potential “flexibility” solution to include in the legislation.

An independent energy policy specialist, who was not involved with the study, described the analysis a “highly valuable addition” after a long period in which parts of the automotive sector claimed there was too little data to properly assess actual emissions.

“These findings show, beyond any doubt, that the difference between official and real-world PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or conventional vehicles,” the expert said. “Any regulatory adjustments regarding PHEVs should be made with utmost caution and in the light of this data.”