Hibernate actually works on many people's computers, to see if does on yours, test it at the cmdline:

$> sudo pm-hibernate

Then turn it back on. If everything works ok, you can permanently add it back to the system menu with these scripts:

https://github.com/repos-ubuntu/tweaks

Need two files:

https://github.com/repos-ubuntu/tweaks/blob/master/reenable-...

https://github.com/repos-ubuntu/tweaks/blob/master/reenable-...

Instructions and links to more detailed instructions in the .sh comments.