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PHEVs release nearly 5x more planet-heating emissions than official figures indicate, according to a recent analysis.

Growing Gap In Official and Real-World Emissions

Statistics shows that PHEVs release just 19% less CO₂ than conventional gas and diesel cars, according to research carried out by a non-profit organization. This differs significantly with lab tests, which assumed a 75% reduction in pollution.

Analysts examined information from onboard energy use monitors of 800,000 vehicles sold in Europe between 2021 and 2023. The team found that real-world CO₂ output from PHEVs in 2023 were 4.9 times greater than lab estimates, increased from three and a half times in 2021.

“Actual CO2 output are rising, while lab-reported figures are decreasing,” stated a lead analyst involved in the report. “This gap is growing and poses a serious issue. Consequently, PHEVs emit nearly as heavily as gasoline cars.”

Key Factors Driving the Discrepancy

Analysts attributed the majority of the gap to inflated estimates of the “electric driving share” – the ratio of miles travelled in electric mode compared to total mileage. The team determined that just 27% of travel was done in electric mode, while lab estimates suggested over four-fifths.

Even, when operating in electric mode, emission levels were significantly higher than official projections. This happened because EV motors were insufficiently powerful sufficient to function alone, leading to combustion motors burning fossil fuels for nearly one-third of the travel covered in EV mode.

Policy and Financial Consequences

Based on estimates, the lowballing of PHEV emissions allowed several large automaker groups to escape over €5bn in fines between 2021 and 2023, by falsely simplifying compliance with EU average fleet CO₂ standards.

Furthermore, owners of PHEVs would pay approximately €500 more annually in running costs than is estimated under lab tests.

“The bold claims that manufacturers often promote about their PHEV cars are obviously far from the truth,” commented a transport analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are little improved than regular gas and diesel vehicles in terms of energy use, CO₂ emissions, and operating expenses.”

Policy Discussion and Automotive Lobbying

Plug-in hybrid cars have recently been drawn again into policy debates as automakers have lobbied the EU to relax CO₂ standards. A proposed ban on new combustion engine vehicles in 2035 has faced intense lobbying from the car sector and resistance from member states with large car industries.

Several high-level politicians have suggested PHEVs as a potential “compromise” solution to include in the regulation.

One external energy policy specialist, who was not involved with the study, called the analysis a “very useful contribution” after years in which segments of the car industry argued there was too little information to properly assess real-world CO2 output.

“These findings demonstrate, beyond any doubt, that the gap in lab and actual PHEV energy use and CO₂ emissions is significantly greater than for petrol or diesel cars,” the expert said. “Any regulatory adjustments regarding PHEVs should be made with extreme care and in the light of that data.”