By default, hibernation is not enabled in Windows 8.
All systems with Windows 8
1. To enable Windows 8 Hibernation option, click battery icon in system tray and then select More power options.
Now, select “Choose what the Power buttons do” option from left sidebar.
2. Now select the option Change settings that are currently unavailable.
3. This will provide you with the option to enable Hibernation. Check Show Hibernate option to enable and click Save Changes.
3. Now you will be able to Hibernate your computer from Windows 8 Power options, which can be accessed from Charms Bar.