Opera browser comes with a built-in battery saving feature. This is a great feature to have when using a laptop that’s unplugged or if want to conserve battery.
When battery saving is enabled, Opera will reduce the background activity of open tabs and also limit reloading or auto fetching of web scripts thereby consuming less power.
To enable this feature, access Opera settings through Menu > Settings or through keyboard shortcut Alt+P.
From the Basic menu tab, scroll down and enable all the options under Battery saver section.
The Always show battery icon on toolbar is a useful icon that can show the current status of the feature from within the browser when clicked.
All done. From now on whenever laptop is unplugged, this feature will be activated and conserve battery automatically.