Eating food
100 Years ago we would have cooked and cleaned our house. We would have needed energy only for cooking and keeping ourselves warm through winter. We would have also required energy for lights. Wood and coal would have been our basic supply. We would have used it for cooking and keeping ourselves warm. For lights we would have used terpentine oil lamps. Or candles. None of these sources of energy are used commonly now. Only Candles are used today.