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PHEVs release almost five times more planet-heating pollution than official data show, as per a new report.

Widening Gap In Official and Real-World CO2 Output

Statistics shows that PHEVs emit only one-fifth lower CO₂ than conventional petrol and diesel cars, based on analysis conducted by a non-profit group. This differs significantly with lab tests, which assumed a three-quarters decrease in pollution.

Analysts studied data from in-vehicle fuel consumption meters of 800,000 vehicles sold in the EU between 2021 and 2023. The team discovered that real-world CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab estimates, up from 3.5 times in 2021.

“Real-world emissions are increasing, while lab-reported figures are falling,” stated a senior researcher participating in the study. “This gap is widening and poses a serious issue. Consequently, PHEVs pollute almost as much as gasoline vehicles.”

Primary Reasons Behind the Discrepancy

Analysts attributed most of the difference to inflated estimates of the “utility factor” – the percentage of miles travelled in battery power relative to overall mileage. They determined that only a quarter of travel was completed in electric mode, while lab estimates assumed over four-fifths.

Even, when running in EV mode, pollution levels were well above lab estimates. This occurred because electric motors were not strong enough to function independently, leading to engines using fossil fuels for nearly a third of the distance covered in EV mode.

Regulatory and Financial Consequences

Based on estimates, the lowballing of PHEV emissions allowed four major automaker groups to escape more than €5bn in fines between 2021 and 2023, by artificially easing compliance with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs would spend approximately €500 extra annually in operating costs than is assumed under laboratory tests.

“The strong statements that manufacturers like to make about their plug-in hybrid cars are clearly far from the truth,” stated a transport analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and saving money. In reality, PHEVs are only slightly better than standard gas and diesel vehicles in terms of fuel use, CO₂ emissions, and operating expenses.”

Policy Debate and Industry Lobbying

Hybrid vehicles have recently been drawn again into political discussions as automakers have lobbied the EU to weaken CO₂ standards. A planned prohibition on sales of new internal combustion cars in 2035 has faced heavy pressure from the automotive industry and opposition from member states with large car manufacturing.

Several senior officials have suggested PHEVs as a possible “flexibility” solution to include in the regulation.

One external energy policy expert, who was not involved with the study, called the analysis a “highly valuable contribution” after years in which parts of the car sector claimed there was too little information to accurately assess actual emissions.

“These findings demonstrate, beyond any doubt, that the difference between lab and actual PHEV fuel consumption and CO₂ output is much, much greater than for gasoline or conventional vehicles,” they stated. “All regulatory adjustments regarding PHEVs should be made with utmost care and considering this evidence.”