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PHEVs produce almost five times greater planet-heating emissions than lab-reported figures indicate, as per a new analysis.

Widening Discrepancy In Official and Actual Emissions

Statistics shows that PHEVs release only 19% lower CO₂ than traditional gas and diesel cars, based on analysis conducted by a advocacy organization. This differs sharply with laboratory tests, which suggested a three-quarters decrease in pollution.

Researchers examined data from in-vehicle fuel consumption meters of eight hundred thousand cars registered in the EU from 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were nearly five times higher than official estimates, up from 3.5 times in 2021.

“Real-world CO2 output are rising, while lab-reported figures are decreasing,” said a lead analyst participating in the report. “This discrepancy is widening and creates a serious problem. As a result, PHEVs emit nearly as heavily as petrol cars.”

Key Reasons Driving the Discrepancy

Analysts attributed the majority of the gap to inflated estimates of the “utility factor” – the ratio of kilometers travelled in electric power relative to total distance. They determined that just a quarter of driving was done in electric mode, whereas official assumptions suggested over four-fifths.

Additionally, when running in electric mode, emission amounts were significantly higher than lab estimates. That happened because electric motors were insufficiently powerful sufficient to function alone, resulting to engines using gasoline for almost a third of the distance covered in electric mode.

Regulatory and Financial Consequences

According to calculations, the underestimation of PHEV CO2 output allowed several large carmaker groups to escape over €5bn in penalties between 2021 and 2023, by falsely easing compliance with European Union fleet-average CO₂ targets.

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

“The bold claims that manufacturers often promote about their plug-in hybrid cars are obviously far from the truth,” stated a transport expert. “Consumers are being misled into thinking that by purchasing a PHEV, they are helping the planet and cutting money. In reality, PHEVs are little better than standard petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and running expenses.”

Policy Debate and Automotive Lobbying

Hybrid vehicles have recently been brought back into political debates as automakers have pressed the EU to weaken CO₂ standards. A planned prohibition on new internal combustion cars in 2035 has faced intense lobbying from the automotive sector and opposition from member states with large car manufacturing.

Several high-level politicians have proposed PHEVs as a possible “compromise” option to include in the legislation.

An independent energy economics specialist, who was unaffiliated with the research, called the report a “very useful contribution” after a long period in which segments of the automotive sector claimed there was insufficient information to accurately evaluate actual CO2 output.

“These findings show, beyond any doubt, that the difference in lab and real-world PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or conventional vehicles,” the expert stated. “All regulatory changes regarding PHEVs should be implemented with utmost caution and considering that evidence.”