Powercfg.exe is a command-line utility that is used from an elevated Windows Command Prompt to control all configurable power system settings, including hardware-specific configurations that are not configurable through the Control Panel, on a per-user basis. It was first introduced by Microsoft in Windows XP SP2 in 2003.
Power schemes are referenced by a GUID (globally unique identifier). When first installed, the default Power Scheme is the "Balanced" scheme. It has a standard GUID of 381b4222-f694-41f0-9685-ff5bb260df2e, which is the same on every computer. Below is an example of a batch script that duplicates the default balanced power scheme, renames it to Custom1, sets custom settings for the scheme, and sets it to be the active scheme. A workstation has multiple power schemes, each with its own custom settings, but only one can be the active scheme (the one currently being used).
POWERCFG -DUPLICATESCHEME 381b4222-f694-41f0-9685-ff5bb260df2e 381b4222-f694-41f0-9685-ff5bb260aaaa POWERCFG -CHANGENAME 381b4222-f694-41f0-9685-ff5bb260aaaa "Custom1" POWERCFG -SETACTIVE 381b4222-f694-41f0-9685-ff5bb260aaaa POWERCFG -Change -monitor-timeout-ac 15 POWERCFG -CHANGE -monitor-timeout-dc 15 POWERCFG -CHANGE -disk-timeout-ac 30 POWERCFG -CHANGE -disk-timeout-dc 30 POWERCFG -CHANGE -standby-timeout-ac 30 POWERCFG -CHANGE -standby-timeout-dc 30 POWERCFG -CHANGE -hibernate-timeout-ac 0 POWERCFG -CHANGE -hibernate-timeout-dc 0