Small working Hydroelectric Cross-Flow Turbine with perfect efficiency. You can print this design with any 3d printer and make it work. This is only the fan of a full hydroelectric station. You can also buy the others pieces from my designs to build a full station. This build is design with small sanyo generators "https://www.ebay.com/itm/40W-Multipurpose-DC-generator-motor-wind-driven-hydroelectric-Hand-generator/273365503559?hash=item3fa5da8e47:g:-zgAAOSwmONbUf12&frcectupt=true".