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PHEVs release almost 5x greater planet-heating pollution than official figures indicate, according to a recent analysis.

Widening Discrepancy Between Lab and Actual Emissions

Statistics reveals that PHEVs release just 19% less CO₂ than conventional petrol and diesel cars, based on analysis carried out by a advocacy group. That differs sharply with laboratory estimates, which suggested a three-quarters reduction in pollution.

Analysts studied information from in-vehicle energy use meters of eight hundred thousand cars registered in Europe from 2021 and 2023. They discovered that real-world CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, up from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are falling,” stated a lead analyst participating in the study. “That discrepancy is growing and creates a significant problem. Consequently, PHEVs emit nearly as heavily as petrol cars.”

Primary Factors Behind the Emissions Gap

Researchers linked most of the difference to inflated estimates of the “utility factor” – the percentage of kilometers driven in battery mode compared to overall distance. They found that just 27% of travel was completed in electric mode, while lab estimates suggested over four-fifths.

Even, when operating in EV mode, emission levels were well above official estimates. This occurred because EV motors were not strong sufficient to function independently, resulting to engines burning gasoline for nearly a third of the travel completed in electric mode.

Policy and Economic Implications

Based on calculations, the lowballing of PHEV emissions allowed several major automaker companies to avoid over €5bn in fines from 2021 and 2023, by falsely easing adherence with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs could spend approximately €500 more annually in running costs than would be assumed under lab conditions.

“The bold claims that manufacturers like to make about their PHEV cars are clearly far from the truth,” commented a automotive expert. “Buyers are being duped into thinking that by purchasing a PHEV, they are helping the planet and cutting costs. Actually, PHEVs are little better than standard gas and diesel cars in terms of fuel consumption, CO₂ production, and operating expenses.”

Political Debate and Industry Lobbying

Plug-in hybrid vehicles have recently been drawn back into policy discussions as automakers have lobbied the European Union to weaken CO₂ targets. A proposed prohibition on new combustion engine vehicles in 2035 has faced heavy pressure from the automotive industry and opposition from member states with significant car manufacturing.

Some high-level politicians have suggested plug-in hybrids as a potential “compromise” option to introduce in the legislation.

An external energy economics expert, who was unaffiliated with the research, described the analysis a “very useful contribution” after a long period in which parts of the car industry argued there was too little information to accurately evaluate actual CO2 output.

“These findings show, beyond any doubt, that the gap between lab and real-world PHEV fuel consumption and CO₂ output is much, much larger than for gasoline or diesel vehicles,” the expert said. “All policy adjustments regarding PHEVs should be made with utmost caution and considering this evidence.”