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Plug-in hybrid cars produce nearly five times greater global warming emissions than official data indicate, as per a recent analysis.

Widening Discrepancy Between Official and Actual Emissions

Statistics shows that PHEVs release only 19% lower CO₂ than conventional gas and diesel vehicles, according to research conducted by a advocacy organization. That contrasts sharply with laboratory estimates, which assumed a 75% decrease in emissions.

Analysts examined information from in-vehicle fuel consumption monitors of 800,000 cars sold in the EU between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab figures, up from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” stated a lead researcher involved in the report. “This discrepancy is widening and poses a serious issue. Consequently, PHEVs pollute almost as heavily as gasoline cars.”

Key Factors Driving the Emissions Gap

Analysts linked the majority of the difference to overestimates of the “utility factor” – the percentage of kilometers driven in battery mode relative to overall mileage. The team found that only 27% of travel was completed in electric mode, while lab assumptions suggested over four-fifths.

Even, when running in EV mode, emission levels were significantly higher than lab projections. That happened because EV motors were not strong enough to operate independently, leading to engines burning gasoline for nearly a third of the travel completed in EV mode.

Regulatory and Economic Consequences

Based on calculations, the underestimation of PHEV emissions allowed four major automaker groups to escape over €5bn in penalties from 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ standards.

Additionally, owners of PHEVs would spend about €500 extra annually in operating costs than would be assumed under laboratory conditions.

“The bold claims that manufacturers like to make about their plug-in hybrid vehicles are clearly way off the mark,” commented a automotive expert. “Buyers are being misled into thinking that by buying a PHEV, they are helping the planet and cutting money. Actually, PHEVs are only slightly improved than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and operating costs.”

Policy Discussion and Industry Lobbying

Hybrid vehicles have recently been brought back into policy discussions as automakers have lobbied the European Union to relax CO₂ standards. A proposed ban on sales of new combustion engine cars in 2035 has faced heavy lobbying from the automotive industry and resistance from EU countries with large car industries.

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

One independent energy economics specialist, who was unaffiliated with the study, described the analysis a “highly valuable addition” after years in which parts of the car sector claimed there was too little data to properly evaluate actual emissions.

“These findings show, beyond any doubt, that the gap between lab and real-world PHEV energy use and CO₂ output is much, much larger than for gasoline or conventional vehicles,” the expert said. “Any policy adjustments regarding PHEVs should be made with extreme care and considering this evidence.”