The greatest challenge of our time is to build a world based on the sustainable use of renewable power. Our massive dependence on fossil fuels has upset the very climatic system that made human evolution possible. The global economy and its financial system are in jeopardy, running hot on overtly cheap yet increasingly costly and fast depleting oil. A 100% renewable world is seen by many as an impossible dream in anything but the very long term. But not only does a growing number of initiatives and plans dare to make the change but many have already achieved it.