Please turn on the light.
I told you not to leave lights on. You don't earn very much, so you'd better cooperate to save on the electricity bill!
When I was little I was afraid of the dark. Now, when I get my electric bill I’m afraid of the light.
Electricity energy is just a fancy way to say electricity.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.