🔗 Share this article

Plug-in hybrid cars produce nearly five times greater global warming emissions than lab-reported figures indicate, as per a new report.

Growing Gap Between Official and Actual Emissions

Data reveals that PHEVs emit just 19% less CO₂ than conventional petrol and diesel cars, based on research conducted by a advocacy group. That contrasts sharply with lab estimates, which suggested a 75% reduction in pollution.

Analysts studied data from onboard energy use meters of 800,000 vehicles registered in the EU from 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than lab figures, up from 3.5 times in 2021.

“Real-world emissions are rising, while official emissions are decreasing,” said a lead researcher participating in the report. “That gap is widening and poses a serious problem. As a result, PHEVs emit nearly as much as gasoline cars.”

Primary Reasons Behind the Emissions Gap

Analysts attributed most of the difference to overestimates of the “electric driving share” – the ratio of miles driven in electric power compared to overall mileage. The team found that just a quarter of driving was done in EV mode, while lab assumptions assumed 84%.

Additionally, when operating in electric mode, pollution levels were significantly higher than lab projections. This occurred because EV motors were not strong sufficient to function alone, leading to combustion motors burning gasoline for nearly a third of the distance completed in EV mode.

Policy and Financial Consequences

Based on estimates, the underestimation of PHEV CO2 output allowed four major automaker groups to escape over €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with European Union fleet-average CO₂ targets.

Furthermore, drivers of PHEVs would pay about €500 more annually in running expenses than is assumed under laboratory conditions.

“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are obviously far from the mark,” stated a transport expert. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are only slightly better than regular gas and diesel vehicles in terms of fuel consumption, CO₂ production, and running expenses.”

Political Debate and Automotive Lobbying

Plug-in hybrid cars have lately been brought again into political debates as automakers have lobbied the EU to relax CO₂ targets. A proposed ban on new combustion engine vehicles in 2035 has faced intense pressure from the automotive sector and resistance from EU countries with large automotive industries.

Some high-level politicians have suggested plug-in hybrids as a possible “flexibility” solution to introduce in the regulation.

One external energy policy specialist, who was unaffiliated with the research, described the report a “very useful contribution” after years in which segments of the automotive sector claimed there was too little information to properly evaluate real-world emissions.

“The results show, beyond any doubt, that the difference between official and actual PHEV energy use and CO₂ output is significantly greater than for gasoline or conventional cars,” they stated. “All policy adjustments concerning PHEVs should be made with extreme caution and in the light of that evidence.”