The hibernate option has been dropped from Ubuntu’s shutdown menu since 12.04 Precise. You can re-enable this feature by following the steps below. Tested on Ubuntu 13.04 Raring, 12.10 Quantal, and 12.04 Precise.
1.) Open a terminal window for running commands. To do it, press Ctrl+Alt+T.
2.) Copy and paste this command into terminal and hit run to create the hibernate configuration file:
sudo gedit /var/lib/polkit-1/localauthority/50-local.d/hibernate.pkla
3.) Copy and paste following lines into the file and save.
[Enable Hibernate] Identity=unix-user:* Action=org.freedesktop.upower.hibernate ResultActive=yes
Now restart your computer.