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PHEVs release nearly five times more planet-heating pollution than official figures indicate, according to a new report.

Growing Discrepancy In Official and Actual CO2 Output

Data shows that PHEVs emit just 19% lower CO₂ than traditional gas and diesel vehicles, according to research carried out by a advocacy group. This contrasts significantly with laboratory tests, which suggested a 75% reduction in pollution.

Analysts studied information from onboard energy use monitors of eight hundred thousand cars sold in the EU between 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.

“Real-world emissions are increasing, while lab-reported emissions are falling,” said a senior analyst participating in the report. “That gap is widening and creates a significant issue. As a result, PHEVs pollute almost as much as petrol cars.”

Primary Factors Driving the Emissions Gap

Researchers linked most of the gap to overestimates of the “electric driving share” – the percentage of kilometers driven in battery mode relative to overall distance. The team determined that just a quarter of driving was completed in EV mode, whereas official assumptions suggested over four-fifths.

Additionally, when operating in electric mode, emission amounts were well above lab projections. That occurred because electric motors were insufficiently powerful sufficient to operate alone, resulting to combustion motors burning fossil fuels for almost one-third of the travel covered in electric mode.

Regulatory and Financial Consequences

Based on calculations, the underestimation of PHEV emissions enabled four large carmaker groups to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying adherence with European Union fleet-average CO₂ targets.

Additionally, drivers of PHEVs could pay about €500 extra per year in operating expenses than is estimated under lab conditions.

“The strong claims that automakers like to make about their PHEV cars are clearly way off the truth,” stated a automotive analyst. “Consumers are being misled into thinking that by buying a PHEV, they are benefiting the planet and saving costs. In reality, PHEVs are only slightly improved than standard gas and diesel vehicles in terms of fuel consumption, CO₂ production, and operating costs.”

Policy Discussion and Industry Pressure

Hybrid vehicles have recently been brought back into policy discussions as carmakers have lobbied the EU to relax CO₂ standards. A proposed prohibition on new combustion engine cars in 2035 has faced heavy lobbying from the car sector and opposition from member states with significant car manufacturing.

Several senior politicians have suggested PHEVs as a potential “compromise” option to include in the legislation.

An independent energy economics expert, who was not involved with the research, described the report a “very useful addition” after years in which segments of the automotive industry claimed there was insufficient information to accurately evaluate real-world CO2 output.

“The results demonstrate, without question, that the gap in lab and real-world PHEV energy use and CO₂ emissions is significantly greater than for gasoline or diesel cars,” they said. “All regulatory adjustments regarding PHEVs should be made with utmost care and in the light of that data.”