run cmd as admin and there:
powercfg/hibernate ON
after that control panel>hardware>power options>change advanced power settings and hibernate is available
that did a trick for windows 2012 server on an old poweredge 1950 server. unfortunately wake on lan refused to work despite of:
in the control panel > network and internet > network connections for the lan interface in the power management > [ ] allow the computer to turn off this device to save power.
so i have to wake the server up via drac.