I'm going to do something today that I have never done before. Ever since I've had a "work" computer, starting in 1994, I've never turned it/them off. I've always left them on as personal testing/staging servers, "just in case" I needed to grab something. It's often been handy (and occasionally essential), being able to SSH into my work system, or run test web apps on it.
I've never given much thought to just how much juice must be sucked up by the systems, even when left running essentially idle evenings and weekends. Apparently, this habit costs US businesses $1.7 BILLION per year.
I really don't care about the financial cost. My portion is likely just a few pennies per day. The University can afford that.
I do care about the incremental effect this is having on the environment, though. In Calgary, much of our juice is generated by burning natural gas. So my leaving a computer on 24/7 is actually pumping CO2 into the air, and helping suck up more of the petro goo that drives this city.
So, when I leave the office this afternoon, I'm shutting down my quad G5 for the weekend. I'll have to modify some of my automated backup scripts, which assume they can run at 3am, but that shouldn't cause too many problems.
I've avoided doing the math to see how many watts drive the quad G5 + 20" Cinema + 17" Dell LCD + 500GB external drive + power to USB devices...