Updating your console could help conserve energy. As you might know, this is "green week" at G4, where we all work together to help out the environment, so listen: According to a recent study, most of the energy your game console consumes is used when it's idle. Roughly 68 percent of all energy consumed by game consoles in 2010 was spent during idle time. In one year, we've wasted 10.8 TWh of energy — or roughly $1.24 billion.
The 360 has an auto shut-off feature, but it was only instituted back in May 2011, so you have to make sure your system is updated. The PlayStation 3, however, has no such feature as a default. You have to set it that way manually. Standardizing the shut-off would save a lot of money and a lot of energy.
The Nintendo Wii, it's worth mentioning, only uses a fraction of the energy of the other consoles.
Source: The Verge