🔗 Share this article

Plug-in hybrid cars emit nearly five times more global warming emissions than official data indicate, as per a new analysis.

Growing Discrepancy In Official and Real-World CO2 Output

Data shows that PHEVs emit just 19% lower CO₂ than conventional petrol and diesel vehicles, based on research conducted by a non-profit group. This contrasts sharply with laboratory estimates, which assumed a three-quarters reduction in pollution.

Researchers examined information from in-vehicle energy use meters of eight hundred thousand vehicles registered in Europe from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while official figures are decreasing,” said a senior analyst participating in the report. “This discrepancy is widening and creates a serious issue. Consequently, PHEVs emit almost as much as petrol cars.”

Primary Factors Behind the Discrepancy

Analysts linked the majority of the gap to overestimates of the “electric driving share” – the percentage of kilometers travelled in electric power compared to total distance. The team found that just a quarter of driving was completed in electric mode, while official estimates assumed 84%.

Additionally, when operating in electric mode, emission amounts were significantly higher than official projections. This happened because electric motors were not strong enough to operate independently, leading to engines using fossil fuels for nearly one-third of the travel completed in EV mode.

Policy and Financial Consequences

According to calculations, the lowballing of PHEV emissions allowed four major carmaker companies to escape more than €5bn in penalties between 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO₂ targets.

Furthermore, owners of PHEVs could pay about €500 more per year in operating costs than would be assumed under lab conditions.

“The strong statements that automakers often promote about their PHEV vehicles are clearly way off the mark,” commented a transport expert. “Buyers are being misled into believing that by buying a PHEV, they are helping the environment and saving money. Actually, PHEVs are only slightly improved than regular gas and diesel cars in terms of fuel consumption, CO₂ emissions, and running costs.”

Political Discussion and Automotive Lobbying

Plug-in hybrid vehicles have lately been brought again into political discussions as carmakers have lobbied the European Union to weaken CO₂ standards. A planned ban on new internal combustion cars in 2035 has faced intense lobbying from the automotive industry and opposition from member states with significant automotive manufacturing.

Some senior politicians have proposed plug-in hybrids as a possible “flexibility” option to introduce in the regulation.

An independent energy policy specialist, who was unaffiliated with the research, called the report a “highly valuable contribution” after a long period in which parts of the car industry claimed there was too little data to properly evaluate actual CO2 output.

“These findings show, beyond any doubt, that the difference in lab and real-world PHEV energy use and CO₂ emissions is significantly greater than for petrol or conventional cars,” the expert said. “Any regulatory changes regarding PHEVs should be implemented with utmost care and in the light of that data.”