Humans have been harnessing the power of water for thousands of years. The potential energy of water has been used to drive mills, pumps and for numerous other applications. Converting the potential and kinetic energy of water to electrical energy however, is a relatively new concept. Modern hydroelectric power plants represent the pinnacle of hydropower engineering, but how do they work? How efficient are they? Are they really 'green'? In this course we are going to answer all of these questions and many more!