On a standard desktop install of Ubuntu, you dont have the option for hibernating. This guide steps you through the process of enabling the hibernation option if your PC can support it.
Test hibernation to make sure it will work on your PC:
(Save any work before doing this test incase hibernation doesnt work and the PC just restarts)
Open a terminal window using ctrl + alt + t
Run the following command to test hibernation:
$ sudo pm-hibernate
If the PC automatically shuts down, and you can resume the system state successfully, you can continue and enable hibernation using the details below.
Create a policy file for the hibernation settings:
$ sudo touch /etc/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla
Open the above file in your favorite text editor
$ sudo vi /etc/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla
Paste in the following text:
[Enable hibernate support] Identity=unix-user:* Action=org.freedesktop.upower.hibernate ResultActive=yes
Save the file and exit the editor.
Restart the PC, or run the following command to kill the menu bar (it will automatically restart)
$ killall unity-panel-service
You should now have ‘hibernate’ as an option when you go to shut down your computer.