Here's what I do for my Slackware (It might help for you, too).
If you want the power down after a while, you must have APM compiled into your kernel and enabled on the desktop. I think SuSE ought to be fairly easy to do with this
2). If all you want is for the display to turn itself off after a period of inactivity, you must add the following line to your
/etc/X11/XF86Config file:
after "Section Monitor"
write
Option "DPMS"
This should enable Display Power management service. Then you can simply go to the control center in X and adjust how much time before you want the monitor to turn itself off.