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PHEVs emit nearly 5x greater planet-heating emissions than lab-reported data show, as per a new report.

Growing Discrepancy Between Official and Actual Emissions

Data reveals that PHEVs release just one-fifth less CO₂ than traditional petrol and diesel cars, according to analysis conducted by a non-profit group. This differs sharply with lab estimates, which suggested a 75% reduction in pollution.

Analysts studied data from onboard energy use monitors of 800,000 vehicles sold in the EU from 2021 and 2023. They found that real-world CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, increased from 3.5 times in 2021.

“Real-world emissions are rising, while official emissions are falling,” said a lead researcher participating in the study. “This gap is growing and creates a significant issue. Consequently, PHEVs emit nearly as much as gasoline cars.”

Primary Reasons Driving the Discrepancy

Researchers attributed the majority of the difference to inflated estimates of the “utility factor” – the percentage of kilometers driven in battery mode compared to overall distance. The team determined that just 27% of travel was done in electric mode, whereas official estimates suggested over four-fifths.

Even, when running in electric mode, pollution levels were significantly higher than official projections. That occurred because EV motors were not strong sufficient to operate alone, leading to engines burning fossil fuels for almost a third of the travel completed in electric mode.

Policy and Economic Consequences

Based on calculations, the underestimation of PHEV CO2 output allowed four major automaker groups to escape over €5bn in fines from 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ targets.

Furthermore, owners of PHEVs would pay approximately €500 extra per year in running expenses than would be assumed under laboratory tests.

“The strong claims that automakers often promote about their PHEV vehicles are obviously way off the mark,” commented a automotive expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. Actually, PHEVs are little improved than regular gas and diesel cars in terms of energy consumption, CO₂ emissions, and operating expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid cars have recently been drawn back into political debates as carmakers have pressed the European Union to weaken CO₂ standards. A proposed prohibition on sales of new combustion engine vehicles in 2035 has faced intense pressure from the car industry and resistance from member states with large car industries.

Several senior officials have suggested PHEVs as a possible “compromise” option to introduce in the regulation.

An external energy economics specialist, who was unaffiliated with the study, described the analysis a “very useful contribution” after a long period in which parts of the car industry argued there was insufficient data to accurately evaluate actual emissions.

“The results demonstrate, without question, that the gap in lab and actual PHEV fuel consumption and CO₂ output is significantly greater than for gasoline or diesel vehicles,” they stated. “Any policy changes regarding PHEVs should be implemented with utmost care and considering that evidence.”