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Plug-in hybrid cars release almost 5x more global warming pollution than lab-reported data indicate, as per a recent analysis.

Growing Discrepancy In Lab and Real-World Emissions

Statistics shows that PHEVs emit only 19% less CO₂ than traditional gas and diesel vehicles, according to analysis carried out by a non-profit group. This differs significantly with laboratory estimates, which assumed a 75% reduction in pollution.

Analysts examined information from in-vehicle fuel consumption monitors 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 higher than lab figures, increased from 3.5 times in 2021.

“Real-world CO2 output are rising, while official figures are falling,” stated a lead analyst involved in the study. “This gap is growing and poses a significant issue. As a result, PHEVs emit nearly as much as petrol vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “electric driving share” – the ratio of kilometers driven in battery mode compared to total distance. The team found that just 27% of driving was done in electric mode, while lab assumptions suggested over four-fifths.

Additionally, when operating in EV mode, pollution amounts were significantly higher than official estimates. This occurred because EV motors were insufficiently powerful enough to function independently, resulting to combustion motors using gasoline for almost one-third of the distance covered in EV mode.

Regulatory and Economic Implications

Based on estimates, the underestimation of PHEV emissions allowed several large carmaker companies to escape over €5bn in penalties from 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ targets.

Additionally, drivers of PHEVs would pay about €500 extra annually in operating expenses than would be assumed under lab tests.

“The strong claims that manufacturers like to make about their plug-in hybrid vehicles are clearly way off the truth,” stated a transport expert. “Buyers are being duped into believing that by buying a PHEV, they are helping the environment and cutting money. In reality, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of fuel use, CO₂ production, and operating expenses.”

Policy Discussion and Industry Pressure

Plug-in hybrid cars have lately been brought again into political discussions as carmakers have pressed the European Union to relax CO₂ targets. A planned ban on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the car sector and resistance from member states with large automotive industries.

Some senior politicians have proposed plug-in hybrids as a possible “compromise” solution to introduce in the regulation.

One external energy economics specialist, who was unaffiliated with the study, called the report a “highly valuable addition” after a long period in which parts of the automotive industry argued there was insufficient data to properly evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the difference in lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for gasoline or conventional cars,” the expert stated. “All policy changes regarding PHEVs should be made with utmost caution and considering this data.”