This key in the registry controls the power profile for an individual login:
[HKEY_CURRENT_USER\Control Panel\PowerCfg]
The power schemes are listed in a subkey and numbered. Set the number of the
scheme you want in CurrentPowerPolicy. This doesn't prevent the user from
changing the policy's details in the control panel however. If you want to
force "Always On" to have a certain config, then you can set that in the
registry too. Set the policy in the control panel, then export the key for
the profile (e.g. Always On) to a reg file. You can then load this reg file
at login with a script.
