We all know rotational energy from our bicycles. lighting used to come from a small rotational energy source attached to a wheel (dynamo light) which produced sufficient electricity to lighten a front and back light. The use of rotational energy, however, is much older than the application on the bicycles, which have been largely replaced by batteries and LED-lights. The first so-called Post-mills stem from Normandy as well as the Rhine riversides around 1200. It took about 800 years to make a splendid comeback as energy source in the age of the „All electric society“ of the 21st century in the making. The „Deutsche Museum of Technology“ in Berlin has great examples of such rotational energy sources on display in the museum‘s park. You can walk a path through the past and future of rotational energy sources.
