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PHEVs produce nearly 5x greater planet-heating pollution than lab-reported figures indicate, as per a new report.

Widening Discrepancy In Lab and Real-World CO2 Output

Data reveals that PHEVs release just one-fifth lower CO₂ than traditional gas and diesel vehicles, according to analysis conducted by a non-profit organization. This differs significantly with laboratory tests, which suggested a three-quarters reduction in pollution.

Researchers studied information from onboard energy use meters of eight hundred thousand vehicles sold in the EU from 2021 and 2023. They found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than official figures, increased from 3.5 times in 2021.

“Real-world emissions are rising, while lab-reported figures are decreasing,” said a lead analyst involved in the study. “That gap is widening and poses a significant issue. As a result, PHEVs emit nearly as heavily as petrol cars.”

Primary Factors Driving the Discrepancy

Researchers linked most of the difference to overestimates of the “utility factor” – the ratio of miles driven in battery power compared to total distance. The team determined that just 27% of travel was done in electric mode, whereas lab estimates suggested over four-fifths.

Additionally, when operating in electric mode, pollution amounts were well above official projections. That occurred because electric motors were not strong enough to operate independently, leading to combustion motors burning gasoline for nearly one-third of the travel covered in EV mode.

Regulatory and Economic Implications

According to estimates, the lowballing of PHEV CO2 output enabled several large automaker groups to avoid over €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs would spend about €500 extra annually in running expenses than would be assumed under laboratory tests.

“The bold statements that automakers often promote about their PHEV vehicles are obviously way off the mark,” commented a automotive expert. “Consumers are being misled into believing that by purchasing a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little improved than standard petrol and diesel vehicles in terms of energy consumption, CO₂ production, and operating expenses.”

Political Discussion and Industry Pressure

Plug-in hybrid cars have recently been brought again into policy discussions as automakers have pressed the European Union to weaken CO₂ targets. A planned prohibition on new internal combustion vehicles in 2035 has faced intense pressure from the car sector and resistance from EU countries with significant car industries.

Some high-level politicians have suggested PHEVs as a potential “flexibility” solution to include in the regulation.

An independent energy economics specialist, who was unaffiliated with the research, described the analysis a “very useful contribution” after years in which parts of the car sector argued there was insufficient information to accurately evaluate actual CO2 output.

“The results demonstrate, beyond any doubt, that the gap between lab and real-world PHEV fuel consumption and CO₂ output is much, much larger than for petrol or conventional cars,” the expert stated. “All policy changes concerning PHEVs should be made with utmost caution and in the light of that evidence.”