Croxley Green pupils spent a day studying by candlelight as they went without electricity at their school last Thursday.
Staff and students at Little Green Junior School, in Lincoln Drive, had no electricity as part of an effort to educate the children about energy consumption.
Janice Tearle, headteacher, said: "Children and staff at Little Green Junior School set themselves the challenge of working in school for the whole day without using any electricity.
"The aim was to raise awareness of how much electricity we use in a day. The whole school joined in.
"Everybody was working without heating, lights or computers with lessons taking place by candlelight and everyone wearing extra layers to stay warm.
"Even the school kitchen joined in by preparing soup cooked on gas and sandwiches for lunch."
A speaker from a renewable energy company visited the school to talk about how wind turbines produce energy.
Instead of listening to music on a CD, children sang songs accompanied by a teacher on the cello.