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Plug-in hybrid electric vehicles emit nearly five times greater global warming pollution than lab-reported data indicate, as per a new report.

Growing Gap In Official and Real-World Emissions

Data reveals that PHEVs release just 19% less CO₂ than conventional petrol and diesel vehicles, according to research conducted by a advocacy organization. This differs sharply with lab tests, which assumed a three-quarters decrease in emissions.

Analysts studied information from in-vehicle energy use monitors of eight hundred thousand cars sold in Europe from 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab figures, up from 3.5 times in 2021.

“Actual emissions are rising, while official figures are decreasing,” stated a lead analyst involved in the report. “This gap is growing and poses a serious issue. Consequently, PHEVs pollute almost as much as petrol vehicles.”

Primary Reasons Driving the Emissions Gap

Researchers linked the majority of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in battery power relative to overall distance. The team determined that just 27% of driving was done in electric mode, whereas lab estimates suggested 84%.

Even, when running in electric mode, emission amounts were significantly higher than official estimates. That occurred because electric motors were not strong sufficient to function alone, leading to engines using fossil fuels for nearly a third of the distance covered in electric mode.

Regulatory and Financial Consequences

According to estimates, the lowballing of PHEV CO2 output allowed several major automaker companies to avoid over €5bn in fines from 2021 and 2023, by artificially easing adherence with European Union average fleet CO₂ standards.

Furthermore, owners of PHEVs could spend approximately €500 more per year in running costs than would be assumed under laboratory conditions.

“The bold statements that automakers often promote about their PHEV cars are obviously far from the mark,” commented a transport expert. “Buyers are being misled into believing that by purchasing a PHEV, they are helping the planet and cutting money. Actually, PHEVs are only slightly improved than regular petrol and diesel cars in terms of energy use, CO₂ emissions, and running expenses.”

Policy Debate and Automotive Lobbying

Hybrid cars have lately been drawn back into policy discussions as automakers have lobbied the EU to weaken CO₂ standards. A proposed ban on new internal combustion cars in 2035 has faced intense pressure from the automotive sector and resistance from EU countries with significant car industries.

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

An independent energy economics specialist, who was not involved with the study, called the analysis a “very useful addition” after a long period in which segments of the automotive industry argued there was too little data to properly assess actual emissions.

“The results demonstrate, beyond any doubt, that the difference in lab and actual PHEV energy use and CO₂ emissions is much, much greater than for petrol or diesel cars,” the expert said. “All policy adjustments regarding PHEVs should be implemented with utmost care and in the light of this evidence.”