NVD-20 Firmware 0.2.168 and later support CEC control, which allows you to turn the connected monitor on and off over HDMI via the web interface.
This is a preliminary guide regarding display compatibility, please report any results to support.
-Samsung displays have no reported issues at this time.
-Please note that with some Sharp displays, you may have to enable the ARC (audio return channel) setting for the unit to be able to be powered back on via the CEC control.