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Plug-in hybrid cars release nearly 5x greater planet-heating emissions than lab-reported figures indicate, as per a recent analysis.

Widening Discrepancy Between Official and Real-World CO2 Output

Statistics shows that PHEVs release just 19% less CO₂ than conventional petrol and diesel vehicles, according to analysis conducted by a advocacy organization. This contrasts significantly with lab tests, which suggested a 75% reduction in pollution.

Analysts examined information from in-vehicle fuel consumption meters of eight hundred thousand vehicles sold in Europe between 2021 and 2023. They found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” said a lead analyst participating in the report. “This gap is widening and poses a significant issue. As a result, PHEVs pollute almost as much as petrol vehicles.”

Primary Reasons Behind the Emissions Gap

Analysts linked most of the difference to overestimates of the “utility factor” – the percentage of kilometers travelled in battery mode relative to overall mileage. They found that only a quarter of driving was completed in electric mode, whereas official estimates assumed over four-fifths.

Even, when operating in EV mode, pollution amounts were well above official estimates. That happened because electric motors were not strong sufficient to function independently, leading to combustion motors burning fossil fuels for nearly a third of the travel completed in EV mode.

Policy and Economic Consequences

Based on calculations, the lowballing of PHEV emissions enabled several large carmaker groups to escape over €5bn in penalties from 2021 and 2023, by falsely easing adherence with European Union fleet-average CO₂ targets.

Additionally, owners of PHEVs could pay about €500 more per year in operating costs than would be estimated under lab tests.

“The bold statements that automakers often promote about their plug-in hybrid vehicles are clearly way off the mark,” stated a transport expert. “Buyers are being duped into thinking that by buying a PHEV, they are helping the planet and cutting money. Actually, PHEVs are little improved than regular gas and diesel cars in terms of energy consumption, CO₂ emissions, and running expenses.”

Policy Debate and Industry Lobbying

Plug-in hybrid cars have recently been drawn back into policy discussions as automakers have lobbied the European Union to weaken CO₂ standards. A proposed prohibition on sales of new combustion engine cars in 2035 has faced intense pressure from the automotive sector and resistance from member states with significant automotive industries.

Some senior officials have proposed PHEVs as a potential “flexibility” option to introduce in the legislation.

One independent energy economics expert, who was not involved with the study, called the report a “highly valuable addition” after years in which segments of the automotive industry argued there was insufficient information to properly assess real-world emissions.

“The results show, beyond any doubt, that the difference in lab and actual PHEV energy use and CO₂ output is much, much larger than for petrol or diesel cars,” the expert stated. “Any regulatory changes regarding PHEVs should be implemented with extreme care and in the light of this evidence.”