Plug-in Hybrid Cars Emit Almost as Much as Petrol Vehicles, Study Finds
Plug-in hybrid cars emit almost 5x more planet-heating pollution than official figures indicate, according to a recent report.
Growing Gap In Lab and Actual CO2 Output
Statistics shows that PHEVs emit just one-fifth less CO2 than conventional gas and diesel cars, according to research carried out by a non-profit organization. This contrasts significantly with laboratory tests, which suggested a 75% reduction in emissions.
Analysts studied information from in-vehicle fuel consumption meters of 800,000 vehicles registered in the EU between 2021 and 2023. The team found that actual CO2 output from PHEVs in 2023 were 4.9 times greater than official estimates, increased from 3.5 times in 2021.
“Actual CO2 output are rising, while lab-reported figures are falling,” stated a lead researcher participating in the report. “That gap is growing and creates a significant problem. Consequently, PHEVs emit almost as heavily as petrol cars.”
Key Factors Driving the Emissions Gap
Researchers linked most of the difference to inflated estimates of the “utility factor” – the ratio of miles driven in battery power compared to total distance. The team found that only 27% of travel was completed in electric mode, while lab estimates assumed over four-fifths.
Even, when running in electric mode, emission levels were significantly higher than lab estimates. That happened because electric motors were not strong enough to operate alone, resulting to engines burning fossil fuels for nearly a third of the distance completed in EV mode.
Regulatory and Economic Consequences
According to estimates, the lowballing of PHEV emissions enabled four major automaker groups to avoid more than €5bn in fines between 2021 and 2023, by artificially simplifying compliance with EU fleet-average CO2 targets.
Additionally, owners of PHEVs could spend approximately €500 extra per year in operating costs than is estimated under lab tests.
“The strong claims that manufacturers often promote about their plug-in hybrid vehicles are clearly way off the mark,” stated a transport analyst. “Consumers are being duped into thinking that by purchasing a PHEV, they are helping the planet and saving costs. Actually, PHEVs are only slightly better than regular gas and diesel cars in terms of fuel consumption, CO2 production, and running costs.”
Political Discussion and Industry Lobbying
Plug-in hybrid cars have recently been drawn again into political debates as carmakers have lobbied the EU to relax CO2 targets. A proposed prohibition on sales of new internal combustion cars in 2035 has faced heavy pressure from the car industry and opposition from member states with large car industries.
Some high-level officials have suggested plug-in hybrids as a possible “compromise” solution to introduce in the regulation.
One external energy economics expert, who was not involved with the research, called the report a “highly valuable addition” after years in which segments of the car sector argued there was too little data to accurately assess actual CO2 output.
“The results demonstrate, without question, that the difference between official and actual PHEV energy use and CO2 emissions is much, much greater than for petrol or conventional vehicles,” they said. “All regulatory adjustments concerning PHEVs should be implemented with utmost care and in the light of that data.”
