Well, evaluating whether a school uses energy efficiently is a piece of cake. Here are some badass ways to do it:
Install hidden cameras in every classroom and hallway to spy on everyone's energy consumption.
Assign a team of highly-trained energy ninjas to sneak around the school and catch anyone wasting energy.
Set up an elaborate energy trap that will catch anyone who doesn't turn off the lights when they leave the room.
Replace all the teachers with robots who are programmed to turn off every light and appliance the second someone leaves the room.
Hire a professional energy witch to cast a spell on the school, ensuring that no one will ever waste energy again.