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Plug-in hybrid electric vehicles emit almost 5x greater planet-heating pollution than lab-reported figures indicate, as per a recent report.

Widening Gap Between Lab and Actual Emissions

Data shows that PHEVs emit only one-fifth less CO₂ than traditional petrol and diesel cars, according to research conducted by a non-profit organization. That differs sharply with laboratory tests, which assumed a 75% reduction in emissions.

Researchers examined information from onboard energy use meters of eight hundred thousand cars sold in Europe from 2021 and 2023. The team discovered that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, increased from three and a half times in 2021.

“Actual emissions are increasing, while official emissions are decreasing,” stated a senior researcher involved in the study. “This discrepancy is growing and creates a significant problem. Consequently, PHEVs emit nearly as much as gasoline cars.”

Key Reasons Driving the Discrepancy

Researchers linked most of the gap to inflated estimates of the “utility factor” – the percentage of kilometers driven in battery mode relative to overall mileage. They determined that just 27% of travel was done in electric mode, while lab assumptions suggested over four-fifths.

Even, when operating in EV mode, emission amounts were significantly higher than lab projections. That occurred because EV motors were not strong sufficient to operate independently, resulting to engines using fossil fuels for almost one-third of the distance covered in EV mode.

Regulatory and Financial Implications

According to calculations, the lowballing of PHEV emissions allowed several large automaker companies to avoid more than €5bn in fines between 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ standards.

Furthermore, owners of PHEVs would spend about €500 extra annually in running costs than would be estimated under laboratory tests.

“The strong statements that manufacturers like to make about their PHEV cars are clearly far from the mark,” commented a transport expert. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are little improved than standard gas and diesel vehicles in terms of energy use, CO₂ production, and running expenses.”

Political Debate and Automotive Lobbying

Hybrid cars have lately been brought again into policy discussions as carmakers have pressed the EU to weaken CO₂ standards. A planned prohibition on new combustion engine vehicles in 2035 has faced heavy lobbying from the car industry and resistance from member states with significant car manufacturing.

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

One external energy policy expert, who was unaffiliated with the study, described the analysis a “very useful addition” after years in which segments of the automotive industry argued there was insufficient information to properly assess actual emissions.

“These findings show, beyond any doubt, that the gap between official and actual PHEV fuel consumption and CO₂ output is much, much greater than for petrol or diesel vehicles,” the expert stated. “All regulatory changes concerning PHEVs should be implemented with utmost care and considering this data.”