How to control electricity with computer

Manage electricity in which sense? do you want to control home appliances or anything else? If you want to control Home Appliances only then it is possible.

I haven't heard much about #-Link-Snipped-# controls recently, but they were all the rage some years ago.

And, of course, there are gobs and gobs of <a href="https://www.google.com/search?q=g+home+automation" target="_blank" rel="nofollow noopener noreferrer">g home automation - Google Search</a> sites that sell goodies you can connect up and control with.

What do you have in mind?