Ubuntu 17.10 and 18.04 automatically suspend laptops running on battery… However, if the laptop is not using battery power, the computer will not automatically suspend..
If you want to save power, you should suspend your computer… not just when running on battery power…
When your computer is suspended, it saves the current state of the machine into the computer memory and power off most functions… a small amount of power is used to keep the content in the memory.. until the system resumes.
When the system resumes, the current state of your session will be restored to allow you to continue from where you left off.This brief tutorial is going to show students and new users how to automatically put Ubuntu desktop in suspend mode to save power and resources.
You can also manually suspend your computer manually… to do that click the system menu on the right side of the top bar. From there you may either hold down the Alt key and click the power off button, or simply long-click the power off button.
Automatically Suspending Ubuntu
If you want Ubuntu to automatically suspend you’re not using the desktop, even on electrical power, the steps below will show you how to do that…
Remember, only when running on battery power will Ubuntu suspend… You can also save power while running on electrical power to save cost… To do that, click the system menu and select system settings..
Then navigate to Power
Then select Automatic suspend and turn it on… After enabling it, click it again to change the power suspend option to automatically suspend on both battery and electrical power…
This will automatically suspend your computer when idle for 20 minutes on battery and 1 hour on electrical power… This
That’s it! This is how to configure Ubuntu to automatically suspend when idle after a specific time.