HOW: Schedule a Hibernation...

If your BIOS supports wake-up by timer, your computer could be setup
to automatically hibernate at say, 1AM and wakeup at say, 8AM (just in
time to run an alarm at 8:05). Your email could be waiting at 8:10.

Personally, I used Macro Express to setup a sleep timer script
programmable from the WinTV remote. Nice!

.
.
.
Anyway, the command-line utility that can initiate hibernation even when run under the task scheduler...
http://www.beyondlogic.org/consulting/shutdown/shutdown.htm
(You don't have to read all that, just search for the word "Download".)

.
Example of a schedule command... (NOTE: AT command uses 24-hour time format)

Code:

AT 01:00 /InterActive "C:\Program Files\CONSOLE\BeyondLogic.Com\ShutDown.Exe" -s hibernate -l 240 -m "Initiating 1AM Scheduled Hibernation."

.
Another example for a 1PM hibernation...

Code:

AT 13:00 /InterActive "C:\Program Files\CONSOLE\BeyondLogic.Com\ShutDown.Exe" -s hibernate -l 240 -m "Initiating 1PM Scheduled Hibernation."

.
.
To get more information on the command-line parameters supported by either AT or ShutDown, "AT /?" or "ShutDown /?".
To open the command prompt, go to "Start Menu" -> "Run" and type "CMD" followed by {Enter} button.