Archimedes Screw Turbine

An Archimedes screw turbine, also called an Archimedean turbine or screw generator, generates electricity from low head hydropower sites by reversing the action of the ancient Archimedes screw: rather than a motor turning the screw to lift water upward, water flowing downward through the helical screw pushes against its blades and turns the screw itself, driving a generator through a gearbox. French engineer Claude-Louis Navier first proposed generating power this way in 1819, and American inventor William Moerschell patented a hydrodynamic version of the design in 1916, though the screw mechanism itself dates back millennia, to water lifting devices recorded in Mesopotamia around 700 BC. The turbine works well at heads as low as 0.1 to 10 meters and flows from 0.01 to 14.5 cubic meters per second, conditions unsuitable for a conventional turbine, and its slow turning blades let fish pass through largely unharmed, earning the design a reputation as a fish friendly hydropower technology. Modern Archimedes screw installations range from small community scale projects to commercial hydropower schemes across Europe and North America.