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PHEVs produce almost five times greater global warming pollution than lab-reported data indicate, as per a recent analysis.

Growing Discrepancy Between Lab and Actual Emissions

Statistics reveals that PHEVs emit only one-fifth less CO₂ than traditional gas and diesel vehicles, based on research carried out by a non-profit organization. This differs sharply with lab tests, which assumed a 75% decrease in emissions.

Researchers examined information from onboard fuel consumption meters of eight hundred thousand cars registered in Europe from 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are decreasing,” stated a senior researcher involved in the report. “This discrepancy is widening and poses a significant problem. As a result, PHEVs pollute almost as much as gasoline vehicles.”

Key Reasons Behind the Emissions Gap

Analysts attributed the majority of the difference to inflated estimates of the “utility factor” – the percentage of miles travelled in electric mode compared to total distance. The team found that only a quarter of travel was completed in electric mode, while lab estimates assumed over four-fifths.

Additionally, when operating in electric mode, emission levels were significantly higher than lab estimates. This happened because EV motors were not strong enough to operate alone, leading to combustion motors using fossil fuels for almost one-third of the travel completed in EV mode.

Policy and Financial Implications

Based on calculations, the lowballing of PHEV CO2 output allowed several major carmaker companies to escape over €5bn in fines between 2021 and 2023, by falsely simplifying adherence with EU fleet-average CO₂ targets.

Additionally, drivers of PHEVs could pay approximately €500 more per year in running expenses than is estimated under lab tests.

“The strong claims that manufacturers often promote about their plug-in hybrid cars are obviously far from the mark,” commented a transport analyst. “Consumers are being misled into thinking that by buying a PHEV, they are helping the environment and cutting money. Actually, PHEVs are only slightly better than standard petrol and diesel cars in terms of energy use, CO₂ production, and running expenses.”

Policy Debate and Industry Lobbying

Hybrid vehicles have lately been drawn back into political debates as automakers have lobbied the European Union to relax CO₂ targets. A proposed prohibition on sales of new combustion engine cars in 2035 has faced intense pressure from the automotive sector and opposition from member states with significant automotive manufacturing.

Several high-level officials have suggested PHEVs as a possible “flexibility” solution to introduce in the legislation.

An external energy economics specialist, who was unaffiliated with the study, called the report a “highly valuable contribution” after a long period in which parts of the automotive sector claimed there was insufficient data to accurately assess real-world CO2 output.

“These findings show, beyond any doubt, that the gap in official and real-world PHEV fuel consumption and CO₂ output is much, much larger than for petrol or diesel cars,” the expert stated. “Any regulatory changes concerning PHEVs should be made with extreme care and in the light of that data.”