🔗 Share this article

Plug-in hybrid cars produce almost 5x more global warming emissions than lab-reported figures indicate, according to a recent report.

Widening Gap Between Lab and Real-World Emissions

Statistics reveals that PHEVs emit just one-fifth lower CO₂ than conventional gas and diesel vehicles, based on research conducted by a advocacy group. This differs significantly with laboratory tests, which suggested a three-quarters decrease in pollution.

Researchers studied data from onboard fuel consumption monitors of eight hundred thousand vehicles registered in the EU from 2021 and 2023. The team discovered that actual CO₂ output from PHEVs in 2023 were nearly five times greater than official estimates, increased from 3.5 times in 2021.

“Real-world CO2 output are increasing, while lab-reported figures are falling,” said a lead researcher participating in the report. “This gap is growing and creates a significant problem. Consequently, PHEVs pollute almost as heavily as gasoline vehicles.”

Primary Reasons Behind the Emissions Gap

Researchers attributed most of the difference to overestimates of the “utility factor” – the ratio of miles driven in battery mode relative to total distance. The team determined that just a quarter of driving was completed in electric mode, while official estimates suggested over four-fifths.

Additionally, when running in EV mode, pollution amounts were well above official projections. This occurred because electric motors were not strong sufficient to function alone, resulting to engines using fossil fuels for nearly one-third of the travel covered in EV mode.

Policy and Financial Consequences

Based on estimates, the lowballing of PHEV emissions enabled four large carmaker groups to avoid more than €5bn in penalties between 2021 and 2023, by falsely easing adherence with European Union average fleet CO₂ targets.

Additionally, drivers of PHEVs could spend about €500 extra per year in running expenses than is estimated under lab tests.

“The strong statements that automakers like to make about their PHEV cars are clearly way off the mark,” commented a automotive analyst. “Buyers are being duped into thinking that by purchasing a PHEV, they are benefiting the environment and cutting money. Actually, PHEVs are only slightly better than standard gas and diesel vehicles in terms of energy use, CO₂ emissions, and running costs.”

Political Debate and Industry Pressure

Plug-in hybrid cars have recently been drawn back into political debates as carmakers have pressed the EU to weaken CO₂ targets. A planned prohibition on new combustion engine vehicles in 2035 has faced intense lobbying from the car industry and opposition from member states with large automotive industries.

Some high-level politicians have suggested PHEVs as a possible “flexibility” solution to introduce in the regulation.

An independent energy policy expert, who was not involved with the research, called the analysis a “very useful addition” after years in which segments of the automotive industry claimed there was too little information to properly assess actual CO2 output.

“The results demonstrate, without question, that the gap between official and actual PHEV fuel consumption and CO₂ emissions is much, much greater than for gasoline or diesel cars,” the expert stated. “All policy adjustments concerning PHEVs should be made with utmost care and considering this evidence.”