As we drive our cars, work on our computers, or even cook food on a wood fire, we probably do not stop to think about where the energy comes from. Right now, all over the world, people are using energy. Get ready for the children whose running feet make the energy to bring water to their village; for the power station that uses warm and cold water to make energy; for the car that saves energy by growing like a plant . But when the gas is gone and there is no more coal - what then? Scientists are finding new answers all the time.