Plug-in Hybrid Vehicles Emit Almost as Heavily as Petrol Vehicles, Study Finds
Plug-in hybrid electric vehicles release nearly five times more global warming pollution than official data show, according to a new analysis.
Widening Gap In Lab and Real-World Emissions
Data reveals that PHEVs emit only one-fifth lower CO2 than conventional petrol and diesel vehicles, based on research conducted by a non-profit organization. That contrasts sharply with lab tests, which suggested a 75% decrease in emissions.
Researchers examined data from in-vehicle energy use monitors of eight hundred thousand vehicles registered in the EU between 2021 and 2023. The team found that actual CO2 emissions from PHEVs in 2023 were 4.9 times higher than official figures, increased from 3.5 times in 2021.
“Actual CO2 output are rising, while official emissions are falling,” said a senior analyst participating in the study. “This discrepancy is growing and poses a serious issue. As a result, PHEVs pollute almost as heavily as gasoline vehicles.”
Primary Factors Behind the Emissions Gap
Analysts attributed most of the gap to overestimates of the “utility factor” – the percentage of kilometers driven in battery mode relative to overall mileage. The team found that only 27% of driving was completed in electric mode, while lab estimates suggested over four-fifths.
Additionally, when operating in electric mode, emission levels were well above lab estimates. This occurred because electric motors were not strong sufficient to function independently, resulting to engines burning gasoline for almost a third of the distance covered in electric mode.
Regulatory and Economic Implications
Based on estimates, the underestimation of PHEV emissions enabled several large automaker companies to escape more than €5bn in penalties between 2021 and 2023, by falsely easing adherence with European Union average fleet CO2 targets.
Furthermore, drivers of PHEVs would pay about €500 more per year in running expenses than would be estimated under lab tests.
“The strong claims that manufacturers like to make about their plug-in hybrid cars are obviously way off the mark,” stated a automotive analyst. “Buyers are being misled into believing that by purchasing a PHEV, they are helping the planet and cutting money. In reality, PHEVs are little better than regular gas and diesel vehicles in terms of fuel consumption, CO2 emissions, and running expenses.”
Political Discussion and Automotive Pressure
Hybrid vehicles have recently been brought again into political discussions as carmakers have pressed the European Union to weaken CO2 targets. A planned prohibition on sales of new internal combustion cars in 2035 has faced heavy lobbying from the car industry and resistance from EU countries with large automotive manufacturing.
Some senior officials have proposed plug-in hybrids as a possible “flexibility” solution to introduce in the regulation.
An independent energy economics expert, who was not involved with the research, described the analysis a “very useful contribution” after a long period in which segments of the automotive industry argued there was insufficient data to properly assess actual CO2 output.
“The results show, beyond any doubt, that the gap between lab and real-world PHEV energy use and CO2 emissions is significantly greater than for gasoline or conventional vehicles,” they said. “All regulatory changes regarding PHEVs should be implemented with utmost caution and considering that evidence.”
