Depends on D20598
I like having it in the context menu. Putting it in the expanded pop-up I'm less sure about, because the icon isn't as recognizable and maybe we might be cluttering the view up too much?
Generally we start menu items with action verbs. And in this case we don't need ellipsis because no further input from the user is required as a part of the action. See https://hig.kde.org/style/writing/labels.html#using-ellipses-in-labels
So for this string, I would recommend "Show Energy Information"