Hydropower a consequence of the natural cyclical transport of water between the earth's surface and the atmosphere Heated by sunlight, followed by precipitation and the downward course of the water in rivers and streams under the force of gravity In a sense the water is the working fluid in an enormous heat engine powered by sunlight 2 E= mgh Modern hydroelectric installations convert the potential energy of water to electric energy at an efficiency of 80 to 90% 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan UniversityHydropower A consequence of the natural cyclical transport of water between the earth’s surface and the atmosphere. Heated by sunlight, followed by precipitation and the downward course of the water in rivers and streams under the force of gravity. In a sense the water is the working fluid in an enormous heat engine powered by sunlight. E= mg∆h = Modern hydroelectric installations convert the potential energy of water to electric energy at an efficiency of 80 to 90%. 2 2 1 mv