The best way to practice is to leave your guitar out 24/7 where you can get to it.
If you have knowledge of midi or at the very least running MP3 files, keep your guitar by your computer at all times so you can start playing at a moments notice.

A lot of guitar players make the mistake of keeping they're guitars in the cases, all wiped down and put at the back of the closet like they're some kind of national treasure or something.

Figure out how to use midi and MP3 files... get a mixer so you can mix your guitar playing in with the background tracks... and any time you feel the urge, just pick it up and go nuts.

Who cares about the amount of electricty you're using by leaving your equipment on.
The important thing is to have everything ready when you need it.