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Plug-in hybrid electric vehicles emit almost five times greater global warming emissions than official figures indicate, as per a recent analysis.

Widening Gap In Official and Actual CO2 Output

Statistics shows that PHEVs release just one-fifth less CO₂ than conventional petrol and diesel vehicles, based on research conducted by a non-profit group. That differs significantly with laboratory tests, which assumed a 75% reduction in pollution.

Researchers examined information from in-vehicle fuel consumption meters of eight hundred thousand cars registered in Europe from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times higher than lab estimates, up from three and a half times in 2021.

“Real-world CO2 output are increasing, while official emissions are falling,” said a senior analyst participating in the study. “That discrepancy is widening and creates a serious issue. As a result, PHEVs emit nearly as much as gasoline vehicles.”

Key Reasons Behind the Emissions Gap

Researchers attributed most of the gap to overestimates of the “utility factor” – the ratio of miles driven in electric mode compared to overall mileage. They found that only 27% of travel was done in EV mode, whereas lab estimates suggested 84%.

Even, when operating in EV mode, emission amounts were significantly higher than official projections. That happened because EV motors were not strong sufficient to operate alone, leading to engines using fossil fuels for almost one-third of the travel completed in EV mode.

Policy and Economic Implications

According to calculations, the underestimation of PHEV emissions allowed four major carmaker groups to escape more than €5bn in penalties between 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would pay about €500 more per year in operating expenses than is assumed under laboratory conditions.

“The bold statements that automakers like to make about their plug-in hybrid cars are clearly far from the mark,” commented a automotive expert. “Buyers are being misled into thinking that by buying a PHEV, they are helping the environment and saving money. Actually, PHEVs are only slightly better than regular petrol and diesel cars in terms of energy consumption, CO₂ production, and operating expenses.”

Policy Discussion and Automotive Lobbying

Hybrid cars have recently been drawn back into policy debates as carmakers have lobbied the European Union to relax CO₂ targets. A proposed ban on new combustion engine cars in 2035 has faced intense pressure from the car industry and opposition from EU countries with significant automotive industries.

Several senior officials have suggested plug-in hybrids as a potential “compromise” option to include in the regulation.

One external energy economics expert, who was unaffiliated with the research, described the report a “very useful addition” after years in which parts of the automotive industry argued there was too little data to accurately assess real-world CO2 output.

“These findings show, beyond any doubt, that the difference between lab and real-world PHEV energy use and CO₂ output is much, much greater than for gasoline or conventional cars,” the expert stated. “All policy adjustments concerning PHEVs should be implemented with utmost caution and in the light of that data.”