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PHEVs release nearly 5x greater global warming pollution than official figures indicate, as per a recent report.

Growing Discrepancy Between Official and Real-World Emissions

Statistics reveals that PHEVs release only one-fifth lower CO₂ than conventional gas and diesel cars, according to research carried out by a advocacy group. That contrasts sharply with laboratory tests, which suggested a three-quarters reduction in emissions.

Researchers examined information from onboard energy use meters of eight hundred thousand vehicles sold in the EU from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times higher than official estimates, up from three and a half times in 2021.

“Actual emissions are rising, while lab-reported figures are decreasing,” said a senior analyst participating in the report. “This discrepancy is widening and poses a serious problem. As a result, PHEVs emit nearly as much as petrol vehicles.”

Primary Factors Driving the Emissions Gap

Researchers linked the majority of the difference to inflated estimates of the “utility factor” – the ratio of miles driven in battery power compared to total distance. They found that only a quarter of travel was done in electric mode, while official estimates suggested 84%.

Even, when running in EV mode, pollution levels were significantly higher than official estimates. That occurred because electric motors were not strong enough to function independently, resulting to engines using gasoline for almost one-third of the distance covered in EV mode.

Policy and Economic Implications

Based on estimates, the underestimation of PHEV CO2 output enabled four major carmaker groups to escape over €5bn in fines from 2021 and 2023, by artificially easing adherence with European Union fleet-average CO₂ standards.

Additionally, owners of PHEVs could spend approximately €500 extra per year in running costs than is assumed under lab conditions.

“The strong claims that manufacturers often promote about their PHEV vehicles are obviously way off the mark,” commented a transport expert. “Consumers are being duped into believing that by buying a PHEV, they are benefiting the planet and cutting money. In reality, PHEVs are little improved than standard gas and diesel cars in terms of energy use, CO₂ emissions, and running costs.”

Political Discussion and Automotive Pressure

Hybrid vehicles have lately been drawn back into policy discussions as carmakers have pressed the EU to weaken CO₂ standards. A planned ban on new internal combustion cars in 2035 has faced intense pressure from the car industry and resistance from EU countries with significant automotive industries.

Several high-level politicians have suggested plug-in hybrids as a possible “compromise” option to include in the regulation.

An independent energy policy expert, who was not involved with the study, called the analysis a “highly valuable contribution” after a long period in which segments of the car industry argued there was insufficient data to accurately assess real-world CO2 output.

“The results show, without question, that the gap in lab and actual PHEV energy use and CO₂ output is much, much larger than for petrol or diesel vehicles,” the expert stated. “Any policy changes regarding PHEVs should be implemented with utmost caution and considering this evidence.”