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PHEVs release nearly 5x greater global warming emissions than lab-reported data indicate, as per a new report.

Growing Discrepancy In Official and Real-World Emissions

Data reveals that PHEVs emit only one-fifth lower CO₂ than traditional gas and diesel cars, based on research carried out by a advocacy organization. This differs significantly with lab tests, which suggested a 75% decrease in emissions.

Analysts examined data from in-vehicle fuel consumption monitors of 800,000 cars sold in the EU between 2021 and 2023. The team found that actual CO₂ output from PHEVs in 2023 were nearly five times greater than lab estimates, up from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official emissions are decreasing,” said a senior researcher involved in the report. “This gap is widening and creates a serious problem. Consequently, PHEVs emit almost as heavily as petrol cars.”

Key Reasons Behind the Emissions Gap

Analysts linked the majority of the gap to overestimates of the “electric driving share” – the ratio of kilometers driven in electric power compared to overall distance. The team determined that just a quarter of travel was done in EV mode, whereas official estimates assumed 84%.

Additionally, when running in electric mode, emission levels were well above lab estimates. That occurred because electric motors were not strong sufficient to operate alone, resulting to engines burning fossil fuels for nearly a third of the travel covered in electric mode.

Regulatory and Financial Consequences

According to estimates, the underestimation of PHEV emissions enabled several large carmaker companies to escape over €5bn in penalties from 2021 and 2023, by artificially easing adherence with EU average fleet CO₂ standards.

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

“The strong claims that automakers often promote about their plug-in hybrid cars are clearly far from the truth,” commented a transport expert. “Buyers are being duped into thinking that by purchasing a PHEV, they are benefiting the planet and cutting costs. Actually, PHEVs are only slightly better than standard gas and diesel cars in terms of energy consumption, CO₂ production, and running costs.”

Political Debate and Industry Lobbying

Hybrid cars have recently been drawn back into political discussions as automakers have pressed the European Union to relax CO₂ standards. A proposed ban on new combustion engine cars in 2035 has faced intense pressure from the automotive sector and resistance from member states with significant automotive industries.

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

An independent energy economics specialist, who was not involved with the study, called the report a “very useful addition” after a long period in which segments of the car industry argued there was too little information to accurately assess actual CO2 output.

“These findings show, beyond any doubt, that the difference between official and real-world PHEV fuel consumption and CO₂ emissions is significantly larger than for petrol or diesel vehicles,” they stated. “Any regulatory adjustments concerning PHEVs should be made with utmost care and in the light of that data.”