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. But when the gas is gone and there is no more coal - what then? Scientists are finding new answers all the time. 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 ...