I had a post a while back about what I was doing to cut costs.
- TLP: Adjusts CPU frequency scaling, PCI‑e ASPM, SATA link power‑management
- Powertop: Used to profile power consumption and has a tune feature sudo powertop --auto-tune
- cpufrequtils: Used to manage the CPU governor directly
- logind.conf: Can be used to put the whole server to sleep when idle
After doing all of that, which does help out during operational hours, I decided to save 10-12 hours of consumption by just shutting it down. The old 'turn the light out if you're not in the room' concept. Right now I am manually booting the server, and it doesn't take that long to resume operations. However, why not employ some automation and magic packets to fire it back up in the morning.
ETA: I do have a watt meter on the server.