It depends on what the computer is doing. My home server runs 24/7 and idles around 80W. I have a backup server at my parents house that uses about the same amount of power but it only needs to be one once a week for an hour while I run my backup. Why would I have it wasting power doing nothing the other 99% of the time? So I have a Raspberry Pi that sets up a reverse SSH tunnel to my house which idles under 2W. I use that to send the Wake On LAN packet to the server.