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PHEVs emit almost five times greater planet-heating pollution than official data indicate, as per a new report.

Growing Gap Between Official and Actual Emissions

Statistics reveals that PHEVs release just 19% lower CO₂ than traditional petrol and diesel vehicles, according to research carried out by a advocacy organization. This differs sharply with lab estimates, which suggested a 75% decrease in pollution.

Analysts studied information from in-vehicle fuel consumption meters of 800,000 cars sold in the EU between 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than official figures, increased from 3.5 times in 2021.

“Actual CO2 output are increasing, while lab-reported emissions are falling,” said a senior researcher participating in the report. “That gap is widening and creates a significant problem. Consequently, PHEVs pollute nearly as much as gasoline vehicles.”

Key Factors Behind the Emissions Gap

Researchers linked most of the gap to inflated estimates of the “utility factor” – the percentage of miles travelled in battery mode relative to total mileage. The team determined that only 27% of driving was completed in EV mode, while lab assumptions assumed over four-fifths.

Additionally, when operating in EV mode, emission levels were significantly higher than lab projections. That occurred because electric motors were insufficiently powerful sufficient to function alone, resulting to combustion motors burning fossil fuels for almost one-third of the travel completed in electric mode.

Regulatory and Economic Consequences

Based on calculations, the underestimation of PHEV CO2 output enabled four major carmaker groups to escape more than €5bn in penalties between 2021 and 2023, by falsely easing compliance with EU average fleet CO₂ targets.

Additionally, owners of PHEVs would spend about €500 more annually in operating expenses than is estimated under laboratory conditions.

“The strong claims that manufacturers often promote about their PHEV cars are obviously far from the truth,” stated a automotive expert. “Buyers are being misled into thinking that by buying a PHEV, they are benefiting the environment and saving money. Actually, PHEVs are only slightly better than regular petrol and diesel vehicles in terms of energy consumption, CO₂ emissions, and running expenses.”

Political Debate and Automotive Pressure

Plug-in hybrid vehicles have recently been brought back into policy discussions as carmakers have pressed the European Union to weaken CO₂ standards. A proposed ban on sales of new combustion engine vehicles in 2035 has faced heavy pressure from the car sector and opposition from EU countries with large car industries.

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

An external energy policy expert, who was unaffiliated with the research, described the report a “highly valuable contribution” after years in which segments of the car sector argued there was insufficient data to properly evaluate actual emissions.

“The results demonstrate, without question, that the gap in official and actual PHEV energy use and CO₂ output is much, much greater than for gasoline or conventional vehicles,” they stated. “All policy changes regarding PHEVs should be made with extreme care and considering that evidence.”