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Plug-in hybrid electric vehicles produce nearly 5x more planet-heating pollution than lab-reported figures show, as per a new analysis.

Widening Gap In Official and Real-World CO2 Output

Data reveals that PHEVs emit only one-fifth lower CO₂ than conventional gas and diesel cars, according to research conducted by a non-profit organization. This differs significantly with lab tests, which suggested a 75% reduction in pollution.

Researchers studied information from onboard energy use monitors of eight hundred thousand cars sold in Europe between 2021 and 2023. The team discovered 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 emissions are increasing, while official emissions are decreasing,” stated a lead analyst participating in the report. “This discrepancy is widening and creates a significant problem. As a result, PHEVs emit almost as heavily as petrol cars.”

Key Reasons Behind the Discrepancy

Researchers linked the majority of the gap to overestimates of the “electric driving share” – the percentage of miles travelled in battery mode compared to total distance. They determined that just a quarter of driving was completed in EV mode, whereas lab assumptions assumed over four-fifths.

Additionally, when running in EV mode, emission levels were significantly higher than lab projections. This occurred because electric motors were insufficiently powerful sufficient to operate independently, leading to engines using fossil fuels for almost one-third of the distance completed in EV mode.

Regulatory and Financial Consequences

Based on estimates, the lowballing of PHEV emissions enabled four major carmaker companies to escape more than €5bn in fines between 2021 and 2023, by artificially simplifying adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs would pay approximately €500 more annually in operating expenses than is assumed under laboratory tests.

“The bold statements that automakers like to make about their PHEV vehicles are obviously far from the truth,” stated a automotive analyst. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and saving money. Actually, PHEVs are little better than standard gas and diesel cars in terms of fuel consumption, CO₂ production, and operating costs.”

Political Debate and Industry Pressure

Plug-in hybrid vehicles have lately been drawn back into political discussions as carmakers have lobbied the EU to relax CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced intense pressure from the automotive sector and opposition from member states with significant car manufacturing.

Several senior politicians have suggested PHEVs as a potential “flexibility” solution to introduce in the regulation.

One external energy economics specialist, who was not involved with the research, called the analysis a “highly valuable contribution” after years in which segments of the car industry argued there was too little information to accurately assess real-world CO2 output.

“These findings show, without question, that the difference between official and real-world PHEV energy use and CO₂ emissions is significantly larger than for gasoline or conventional cars,” they said. “Any policy adjustments regarding PHEVs should be implemented with extreme caution and in the light of that data.”