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PHEVs emit nearly five times greater planet-heating emissions than lab-reported data indicate, according to a recent analysis.

Widening Gap In Official and Actual Emissions

Data reveals that PHEVs release just one-fifth less CO₂ than conventional petrol and diesel cars, based on research carried out by a advocacy organization. This contrasts sharply with lab estimates, which suggested a 75% decrease in pollution.

Researchers examined information from onboard fuel consumption monitors of 800,000 vehicles registered in Europe between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, up from three and a half times in 2021.

“Actual CO2 output are rising, while official figures are decreasing,” stated a senior analyst involved in the study. “That discrepancy is widening and poses a significant issue. As a result, PHEVs emit almost as much as petrol vehicles.”

Key Factors Behind the Emissions Gap

Researchers attributed the majority of the gap to inflated estimates of the “utility factor” – the percentage of kilometers travelled in battery mode relative to overall distance. They found that only 27% of driving was completed in EV mode, while official assumptions assumed 84%.

Additionally, when running in electric mode, emission amounts were significantly higher than lab projections. This happened because electric motors were not strong enough to operate independently, resulting to combustion motors using fossil fuels for nearly a third of the travel covered in EV mode.

Regulatory and Economic Consequences

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

Additionally, drivers of PHEVs would spend about €500 extra annually in operating expenses than is estimated under laboratory conditions.

“The bold claims that manufacturers like to make about their plug-in hybrid vehicles are clearly far from the truth,” commented a automotive analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping 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 operating costs.”

Political Discussion and Industry Pressure

Hybrid vehicles have lately been drawn again into political discussions as carmakers have lobbied the EU to relax CO₂ standards. A planned ban on new combustion engine cars in 2035 has faced heavy lobbying from the automotive sector and opposition from member states with large car manufacturing.

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

One external energy policy specialist, who was unaffiliated with the research, described the report a “highly valuable contribution” after years in which segments of the car industry argued there was insufficient data to properly evaluate real-world emissions.

“These findings demonstrate, beyond any doubt, that the difference between lab and real-world PHEV fuel consumption and CO₂ output is significantly larger than for petrol or diesel vehicles,” the expert said. “All regulatory adjustments regarding PHEVs should be made with utmost caution and in the light of this evidence.”