A report out of US University Carnegie Mellon
), based on a study conducted throughout 2010, estimates that idling video game consoles were responsible for somewhere in the vicinity of 10.8 Terawatt hours of wasted energy consumption, with a rough cost of around US$1.24 billion over the course of the year.
The wastage is largely attributed to the average user's bad habits of leaving game consoles running while not in use and their device auto-off features not being enabled, as well as the high wattage that modern consoles consume compared to their predecessors.
Verge notes that an Xbox 360 firmware update last year has since enabled that console's auto-off functionality by default, but the PlayStation 3, which reportedly sucks the most idling juice of the current consoles (around 177 Watts), still requires users to manually enable its auto-off feature.
Turn your consoles off when not using them people!