Energy use and power-saving settings

Every digital system uses electricity while it is on, and the amount depends on three things: the device (a large desktop draws more than a phone), its settings (a bright screen or active Wi-Fi uses more power) and how you use it (gaming or video streaming uses more than typing a document). A usage and settings policy is a set of rules or defaults that reduce this energy use and help a battery last longer between charges.

Automatic power settings

Auto power off schedules a device to shut down at a set time, so it cannot be left running overnight by accident, which saves electricity. Auto sleep (standby) puts a device into a low-power state after a period of non-use: the screen turns off and the processor slows right down, cutting power use while keeping your work ready. An animated screen saver does not save power, because the screen and system still draw almost the same current.

Everyday power-saving choices

• Lower the screen brightness: the display is one of the biggest power users, so dimming it reduces power consumption and the device needs charging less often.
• Turn off Wi-Fi and Bluetooth when not needed: these radios use power to search for networks and stay connected.
• Close unused tabs and apps: each open tab or app keeps the processor working and memory in use, so closing them means less processing and less power drawn.
• Use airplane mode or low power mode: airplane mode switches off the wireless radios, while low power mode limits non-essential tasks such as automatic updates and visual effects, so the battery lasts longer.

For example, a phone used on a long coach trip for revision videos and music might fall to 20% battery if the screen stays at full brightness, Bluetooth headphones stay connected and several apps are left open. A shorter idle time before standby, a dimmer screen, closed apps and low power mode can leave enough charge to last until arrival. Organisations often apply these settings across all their devices as a policy, rather than relying on each person to remember.