Powering the Future. The Stone Age did not end because the world ran out of stone, and the fossil-fuel age will not end because we run out of coal and oil. Alex Kirby explores a future in which all our energy needs are met from clean, renewable sources such as solar, wind and wave power. Cars are likely to run on hydrogen harvested from green algae- in otherwords, the garden pond could end up being used to power the family saloon and forests of willows might be fuelling thousands of local power stations. Producer Brian King