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PHEVs produce almost 5x more global warming emissions than official data indicate, as per a new analysis.

Widening Discrepancy In Official and Real-World Emissions

Statistics shows that PHEVs release just one-fifth lower CO₂ than conventional petrol and diesel vehicles, according to analysis conducted by a non-profit organization. That differs sharply with laboratory tests, which assumed a three-quarters decrease in emissions.

Analysts examined information from in-vehicle energy use monitors of eight hundred thousand vehicles registered in Europe from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times higher than lab figures, up from three and a half times in 2021.

“Real-world emissions are increasing, while official emissions are decreasing,” stated a senior analyst participating in the study. “This discrepancy is growing and creates a significant issue. As a result, PHEVs pollute nearly as much as petrol vehicles.”

Key Reasons Driving the Emissions Gap

Researchers linked the majority of the gap to overestimates of the “utility factor” – the percentage of miles driven in electric mode compared to overall distance. The team found that just a quarter of driving was done in electric mode, whereas official assumptions assumed over four-fifths.

Even, when running in electric mode, pollution amounts were well above lab projections. That happened because EV motors were not strong sufficient to operate alone, resulting to engines burning fossil fuels for almost a third of the distance completed in electric mode.

Regulatory and Financial Implications

According to estimates, the underestimation of PHEV emissions allowed several large carmaker groups to avoid more than €5bn in penalties between 2021 and 2023, by artificially simplifying adherence with European Union average fleet CO₂ targets.

Furthermore, owners of PHEVs would spend about €500 extra annually in running costs than would be assumed under laboratory conditions.

“The strong statements that manufacturers like to make about their plug-in hybrid cars are clearly way off the mark,” commented a automotive expert. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are only slightly improved than regular petrol and diesel vehicles in terms of fuel use, CO₂ emissions, and operating expenses.”

Policy Debate and Automotive Pressure

Hybrid cars have lately been brought again into political discussions as carmakers have pressed the European Union to weaken CO₂ standards. A proposed prohibition on sales of new internal combustion cars in 2035 has faced heavy pressure from the automotive sector and resistance from member states with significant automotive industries.

Several senior politicians have proposed PHEVs as a potential “compromise” option to include in the legislation.

One independent energy policy specialist, who was unaffiliated with the research, called the report a “very useful contribution” after years in which parts of the automotive sector argued there was insufficient data to accurately evaluate actual emissions.

“The results demonstrate, without question, that the difference in lab and real-world PHEV energy use and CO₂ output is significantly larger than for petrol or diesel vehicles,” the expert stated. “Any regulatory adjustments regarding PHEVs should be made with utmost caution and in the light of this evidence.”