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PHEVs release nearly five times greater global warming pollution than lab-reported figures indicate, as per a recent report.

Widening Gap In Lab and Real-World CO2 Output

Statistics shows that PHEVs release only one-fifth less CO₂ than conventional petrol and diesel vehicles, based on research carried out by a non-profit group. That differs significantly with lab tests, which assumed a three-quarters decrease in pollution.

Analysts examined information from onboard energy use meters of 800,000 vehicles sold in Europe from 2021 and 2023. They found that actual CO₂ emissions from PHEVs in 2023 were nearly five times greater than lab figures, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while lab-reported figures are decreasing,” stated a lead researcher involved in the report. “This discrepancy is growing and poses a serious problem. As a result, PHEVs pollute nearly as much as gasoline vehicles.”

Primary Factors Driving the Discrepancy

Analysts attributed the majority of the difference to overestimates of the “electric driving share” – the percentage of miles driven in battery mode compared to total mileage. They determined that just a quarter of travel was done in electric mode, whereas official estimates assumed 84%.

Even, when running in electric mode, pollution amounts were significantly higher than official projections. This occurred because EV motors were insufficiently powerful sufficient to operate alone, leading to engines using gasoline for nearly one-third of the travel covered in EV mode.

Policy and Financial Implications

Based on calculations, the underestimation of PHEV CO2 output enabled four large automaker companies to escape over €5bn in penalties from 2021 and 2023, by falsely easing compliance with European Union average fleet CO₂ targets.

Additionally, owners of PHEVs could spend approximately €500 more per year in operating expenses than would be estimated under laboratory tests.

“The bold claims that automakers often promote about their PHEV vehicles are clearly far from the truth,” commented a transport analyst. “Buyers are being duped into believing that by buying a PHEV, they are helping the environment and cutting costs. In reality, PHEVs are little improved than regular petrol and diesel vehicles in terms of energy use, CO₂ emissions, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have recently been brought back into policy discussions as automakers have lobbied the European Union to weaken CO₂ targets. A planned prohibition on sales of new combustion engine cars in 2035 has faced intense pressure from the car industry and resistance from EU countries with significant automotive manufacturing.

Several high-level politicians have proposed plug-in hybrids as a potential “compromise” solution to include in the legislation.

One independent energy policy specialist, who was unaffiliated with the study, described the analysis a “very useful addition” after years in which parts of the car sector argued there was too little data to accurately assess real-world CO2 output.

“These findings show, beyond any doubt, that the difference in lab and actual PHEV energy use and CO₂ output is significantly greater than for gasoline or diesel cars,” they stated. “All regulatory adjustments regarding PHEVs should be implemented with utmost care and considering this evidence.”