This document discusses hydroelectric power as a renewable energy source. It notes that hydroelectricity generates 16% of global electricity, with China being the largest producer. In India, hydroelectric power has a potential of over 84,000 MW, with the Ganges, Brahmaputra, and Indus rivers contributing 80% of potential. Currently India has harnessed only 15% of its hydroelectric potential. The document outlines benefits of hydroelectricity such as being renewable, providing reliable base load power, and enabling development in remote areas. However, it also lists challenges like difficult terrain, delays in land acquisition and permits, and potential ecological and fishery impacts.