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PHEVs emit nearly 5x more global warming emissions than official figures indicate, according to a new report.

Growing Discrepancy In Lab and Real-World CO2 Output

Statistics shows that PHEVs release only 19% less CO₂ than traditional petrol and diesel cars, based on research carried out by a advocacy organization. This differs significantly with laboratory tests, which assumed a three-quarters decrease in emissions.

Researchers studied data from in-vehicle energy use meters of eight hundred thousand cars sold in the EU from 2021 and 2023. The team found that real-world CO₂ emissions from PHEVs in 2023 were 4.9 times greater than lab figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while lab-reported figures are decreasing,” said a senior analyst involved in the report. “That gap is growing and creates a serious issue. Consequently, PHEVs pollute almost as heavily as gasoline cars.”

Key Reasons Behind the Discrepancy

Analysts linked most of the difference to overestimates of the “utility factor” – the percentage of miles travelled in electric power compared to total distance. They found that just a quarter of travel was completed in EV mode, while lab estimates suggested over four-fifths.

Additionally, when running in electric mode, pollution levels were significantly higher than official projections. That occurred because EV motors were not strong sufficient to operate independently, resulting to combustion motors using gasoline for almost a third of the travel completed in EV mode.

Regulatory and Financial Consequences

According to estimates, the lowballing of PHEV emissions enabled several major carmaker groups to avoid over €5bn in fines from 2021 and 2023, by artificially simplifying adherence with EU average fleet CO₂ standards.

Furthermore, drivers of PHEVs could pay approximately €500 more per year in running costs than is estimated under lab conditions.

“The strong claims that manufacturers often promote about their PHEV cars are obviously way off the mark,” stated a transport expert. “Buyers are being duped into thinking that by purchasing a PHEV, they are helping the planet and cutting money. In reality, PHEVs are only slightly improved than standard gas and diesel vehicles in terms of fuel use, CO₂ production, and running expenses.”

Political Discussion and Industry Lobbying

Plug-in hybrid cars have recently been brought again into political discussions as automakers have pressed the European Union to weaken CO₂ standards. A proposed ban on new internal combustion vehicles in 2035 has faced heavy pressure from the automotive industry and resistance from EU countries with significant car manufacturing.

Several high-level politicians have proposed PHEVs as a possible “flexibility” solution to include in the legislation.

One external energy economics expert, who was unaffiliated with the research, described the report a “highly valuable contribution” after a long period in which parts of the automotive industry argued there was too little data to accurately assess real-world emissions.

“The results demonstrate, beyond any doubt, that the difference in lab and actual PHEV fuel consumption and CO₂ emissions is much, much larger than for petrol or conventional vehicles,” they stated. “All regulatory changes regarding PHEVs should be made with utmost care and considering that data.”