

The smallest wave movements can be converted into electricity.
Air streams, meanwhile, power wind turbines. But their enormous blades take up a lot of space and only last for 15 years.
Instead of vibrating alternatives without blades, a founder from New York is backing a slender design whose vertical axis is divided into individual floors like a building.
Fixed blades mounted at intervals on the exterior guide the airstream inside, causing a horizontally installed paddle wheel on each floor to turn, and filling a hydraulically powered storage battery.
The energy can be used on the spot by companies or electric vehicles.
Wind turbines with warning systems could protect birds or (when decommissioned) provide a little something extra in playgrounds.