There was a time when no one had what we today call power. Fire and the sun provided light. Now though we all wake up and expect to have power, and we all are sometimes disappointed. We are accustomed to this convenience. In your creative nonfiction piece you capture the sense of loss, and sometimes even desperation we feel when power is taken away. You add the worrying factor of your roommate's absence. This reinforces the sense of being out of control in the piece.
It might be said that the piece has a weak arc, and is more about the report of an experience. However, you do manage to give your narrative an arc of sorts. The conflict, though not dramatic, is mostly a conflict with yourself and the regret about failing to plug in the phone.
Nicely told, @iskawrites.