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PHEVs emit nearly 5x greater global warming emissions than official data indicate, as per a new analysis.

Widening Discrepancy In Lab and Actual CO2 Output

Data shows that PHEVs emit only 19% lower CO₂ than traditional gas and diesel vehicles, based on analysis conducted by a advocacy organization. That differs sharply with lab estimates, which suggested a three-quarters reduction in emissions.

Analysts examined information from onboard fuel consumption monitors of eight hundred thousand cars sold in the EU between 2021 and 2023. They discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, increased from three and a half times in 2021.

“Real-world CO2 output are rising, while lab-reported emissions are decreasing,” said a lead researcher involved in the study. “This gap is widening and poses a significant problem. As a result, PHEVs pollute nearly as heavily as gasoline vehicles.”

Primary Factors Behind the Discrepancy

Analysts linked most of the difference to inflated estimates of the “electric driving share” – the percentage of kilometers travelled in electric mode relative to total distance. The team found that just 27% of driving was completed in EV mode, whereas official estimates assumed 84%.

Additionally, when running in electric mode, pollution levels were well above official projections. This happened because EV motors were insufficiently powerful enough to operate alone, resulting to combustion motors using fossil fuels for nearly a third of the travel completed in electric mode.

Policy and Economic Implications

Based on estimates, the underestimation of PHEV CO2 output enabled several major carmaker groups to avoid more than €5bn in penalties from 2021 and 2023, by falsely simplifying compliance with European Union fleet-average CO₂ targets.

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

“The bold statements that automakers like to make about their plug-in hybrid vehicles are clearly way off the truth,” stated a automotive analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving costs. In reality, PHEVs are only slightly improved than standard gas and diesel cars in terms of energy consumption, CO₂ emissions, and running expenses.”

Policy Debate and Automotive Lobbying

Plug-in hybrid vehicles have lately been brought back into policy discussions as automakers have lobbied the EU to relax CO₂ targets. A planned prohibition on new internal combustion vehicles in 2035 has faced intense lobbying from the automotive sector and opposition from EU countries with significant car industries.

Some senior officials have suggested PHEVs as a potential “flexibility” solution to introduce in the regulation.

One external energy policy specialist, who was unaffiliated with the research, described the report a “very useful addition” after years in which segments of the automotive sector claimed there was insufficient data to accurately evaluate real-world CO2 output.

“These findings demonstrate, without question, that the difference between official and actual PHEV fuel consumption and CO₂ emissions is significantly greater than for gasoline or conventional vehicles,” the expert said. “All regulatory changes regarding PHEVs should be made with utmost caution and considering that data.”