The International Council on Clean Transportation (ICCT) is behind the study.
Real-world fuel consumption numbers are 42%-67% higher than rated.
This isn’t the first time that studies reveal that plug-in hybrid vehicles are not the hyper-fuel-efficient vehicles they are marketed to be. The finding, or realization, comes from the fact that owners are not as inclined to plug in as often as they should to benefit from the presence of the large battery.
The most recent study, completed by International Council on Clean Transportation (ICCT), using self-reported fuel economy figures cumulated on Fuelly.com and data for engine-off distances traveled collected by the California Bureau of Automotive Repair (BAR), shows that ratings and real-world consumption rarely if ever align.
The bottom line is that the study found that “real-world electric drive share maybe 26%–56% lower and real-world fuel consumption maybe 42%–67% higher than assumed within EPA’s labeling program for light-duty vehicles.”
This investigation was spurred by some investigations into the real-world performance of PHEVs in Europe and China. As we’ve reported in the recent past, some countries have partially or completely cut incentives on the purchase or lease of new PHEVs.
The ICCT makes a few recommendations including a downward adjustment to the regulatory utility factor for PHEVs to reflect current real-world performance.