Greenpeace, the EPA is concerned about the energy uses of home consoles. They plan to introduce new energy requirements for home consoles starting July 1, 2010 as part of its Energy Star program. These new requirements include an auto off function, a sleep mode for television/display, power scaling and a wireless access point function that will use less than 10 watts of power.
Seeing as how the Wii already uses less power than its competitors, it shouldn't be too much of a hassle for Nintendo to include these functions. Why 2010 though? The EPA hopes that's enough lead time for console manufacturers to institute these new features.