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Plug-in hybrid electric vehicles produce almost five times more planet-heating pollution than lab-reported figures show, as per a recent analysis.

Widening Gap Between Official and Real-World CO2 Output

Statistics reveals that PHEVs release only one-fifth lower CO₂ than traditional petrol and diesel vehicles, according to research conducted by a advocacy group. That contrasts sharply with laboratory estimates, which suggested a three-quarters decrease in pollution.

Analysts studied data from onboard fuel consumption meters of 800,000 cars sold in the EU from 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are falling,” stated a senior analyst participating in the report. “This discrepancy is growing and poses a serious problem. As a result, PHEVs pollute nearly as heavily as petrol cars.”

Primary Factors Driving the Discrepancy

Analysts attributed the majority of the difference to inflated estimates of the “utility factor” – the ratio of miles driven in battery power relative to overall distance. They found that just 27% of travel was completed in electric mode, whereas official assumptions assumed over four-fifths.

Additionally, when operating in EV mode, emission levels were well above official projections. That happened because EV motors were not strong enough to function independently, resulting to combustion motors using gasoline for nearly one-third of the distance completed in electric mode.

Policy and Economic Implications

According to estimates, the lowballing of PHEV emissions allowed four large carmaker groups to avoid over €5bn in penalties between 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ standards.

Furthermore, drivers of PHEVs would pay about €500 more per year in running costs than would be assumed under lab conditions.

“The bold statements that automakers often promote about their plug-in hybrid vehicles are clearly far from the mark,” stated a automotive analyst. “Buyers are being misled into thinking that by purchasing a PHEV, they are helping the planet and cutting money. Actually, PHEVs are little better than regular gas and diesel vehicles in terms of energy consumption, CO₂ emissions, and running costs.”

Political Discussion and Industry Pressure

Plug-in hybrid vehicles have lately been drawn back into policy debates as automakers have pressed the EU to weaken CO₂ standards. A planned prohibition on new combustion engine vehicles in 2035 has faced intense lobbying from the automotive industry and opposition from member states with significant automotive manufacturing.

Some high-level politicians have suggested PHEVs as a potential “flexibility” option to introduce in the regulation.

An independent energy economics specialist, who was unaffiliated with the research, called the report a “very useful contribution” after years in which parts of the car sector claimed there was too little data to accurately assess actual CO2 output.

“These findings show, without question, that the gap between lab and actual PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or diesel cars,” the expert stated. “Any regulatory adjustments concerning PHEVs should be made with extreme caution and in the light of that evidence.”