🔗 Share this article

PHEVs produce nearly 5x greater global warming emissions than lab-reported data indicate, according to a new report.

Widening Discrepancy In Lab and Actual Emissions

Statistics reveals that PHEVs emit just one-fifth lower CO₂ than traditional gas and diesel vehicles, according to analysis conducted by a advocacy group. This contrasts significantly with lab estimates, which assumed a three-quarters decrease in pollution.

Researchers studied data from in-vehicle fuel consumption monitors of 800,000 vehicles registered in the EU between 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were 4.9 times higher than official figures, increased from three and a half times in 2021.

“Actual CO2 output are increasing, while official emissions are decreasing,” said a lead analyst involved in the report. “That discrepancy is widening and poses a significant problem. As a result, PHEVs pollute almost as much as gasoline vehicles.”

Primary Factors Behind the Emissions Gap

Analysts attributed the majority of the difference to overestimates of the “electric driving share” – the ratio of kilometers driven in electric mode relative to overall distance. The team determined that only 27% of travel was completed in electric mode, while lab estimates assumed 84%.

Even, when running in electric mode, pollution amounts were significantly higher than official estimates. This occurred because electric motors were not strong enough to function independently, resulting to engines burning fossil fuels for nearly a third of the travel completed in electric mode.

Regulatory and Financial Implications

According to estimates, the underestimation of PHEV emissions enabled four major carmaker companies to escape more than €5bn in penalties between 2021 and 2023, by falsely simplifying compliance with EU fleet-average CO₂ standards.

Furthermore, owners of PHEVs would spend about €500 more annually in operating expenses than would be assumed under laboratory conditions.

“The strong statements that manufacturers like to make about their plug-in hybrid vehicles are obviously far from the truth,” stated a transport analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and cutting costs. In reality, PHEVs are little better than regular petrol and diesel vehicles in terms of fuel consumption, CO₂ production, and operating costs.”

Political Discussion and Industry Lobbying

Plug-in hybrid vehicles have lately been drawn again into political discussions as carmakers have pressed the European Union to weaken CO₂ standards. A planned ban on new combustion engine vehicles in 2035 has faced heavy pressure from the car industry and resistance from EU countries with significant car industries.

Several high-level officials have suggested plug-in hybrids as a potential “flexibility” solution to introduce in the legislation.

One external energy policy specialist, who was unaffiliated with the study, described the report a “highly valuable addition” after a long period in which parts of the automotive industry argued there was too little data to properly evaluate actual CO2 output.

“The results show, without question, that the gap in lab and real-world PHEV energy use and CO₂ emissions is much, much greater than for petrol or diesel vehicles,” they stated. “Any policy changes concerning PHEVs should be made with utmost care and considering that evidence.”