Plug-in hybrid cars, long sold as the perfect bridge between gasoline and electric vehicles, are turning out to be far dirtier than manufacturers claimed. A sweeping new analysis by Transport and Environment, based on data from more than 127,000 plug-in hybrids across Europe, found that real-world carbon dioxide emissions are nearly five times higher than what official laboratory tests show.
According to the study, these cars emit an average of 139 grams of CO2 per kilometre, compared with the 28 grams claimed under the official WLTP testing procedure. The reason for the massive discrepancy lies in how manufacturers test their vehicles. Laboratory simulations assume drivers use electric power for about 80 percent of their trips. In reality, most drivers rely on the petrol or diesel engine almost three quarters of the time.
Many plug-in hybrids, marketed as clean, efficient commuter cars, are being used by company fleets whose drivers often skip charging altogether. With employer fuel cards covering the cost of petrol, there is little incentive to plug in. The result is a heavier, more complex vehicle burning more fuel than conventional models while carrying the extra weight of a large, mostly unused battery pack.
Transport and Environment researchers warn that lawmakers have been misled by optimistic testing data. “Real-world emissions are going up while official numbers go down,” said Sofia Navas Gohlke, co-author of the report. The organisation estimates that plug-in hybrids emit only nineteen percent less CO2 than traditional gasoline and diesel cars, far from the seventy-five percent reduction claimed when the technology was first introduced.
Manufacturers continue to market these vehicles as green choices, but environmental analysts now call plug-in hybrids a stopgap that delays the transition to full electrification. The revelations have rattled European regulators, who are debating whether hybrids should continue to qualify as low-emission vehicles.
