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 University
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. 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
Hydropower Condensation m Condensation and deposition and deposition niin 1111 thn Ice-\'Precipitation Evaporation A pRecipitation 二 Hydroelectric plant Evaporation …,…,mman: ∴…‘",,,," Underground,… Ocean ∴3. Figure 5.2 The hydrologic cycle. Electricity is produced in the hydroelectric plant by the action of water against a turbine connected to a generator. In this way the stored potential energy of the water in the reservoir becomes electrical energy 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan University
Hydropower Figure 5.2 The hydrologic cycle. Electricity is produced in the hydroelectric plant by the action of water against a turbine connected to a generator. In this way the stored potential energy of the water in the reservoir becomes electrical energy
eg. Calculate the flow rate of water(in liters/sec=kilograms/sec)required to provide lkw of electric power if the water falls a vertical distance of 90m Assume 80% conversion efficiency. (1.42liters/sec) 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan University
eg. Calculate the flow rate of water (in liters/sec = kilograms/sec) required to provide 1kW of electric power if the water falls a vertical distance of 90m. Assume 80% conversion efficiency. (1.42liters/sec)
Advantages No polluting emissions into the air or water No waste heat is rejected as thermal pollution Lifetimes of many decades small maintenance requirements Respond well to sudden changes in demand, making hydroelectricity well suited to matching peak loads The dams can serve multiple purposes Water stored for irrigation flood control municipal drinking water supply, power a hydroelectric plant 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan University
Advantages: No polluting emissions into the air or water No waste heat is rejected as thermal pollution Lifetimes of many decades small maintenance requirements. Respond well to sudden changes in demand, making hydroelectricity well suited to matching peak loads. The dams can serve multiple purposes; Water stored for irrigation, flood control, municipal drinking water supply, power a hydroelectric plant
In the late 1980s Boulder. 6MW.8% of electricity power used in the city The payback time for this system is 10 ears,the city is making a pI investment. Through sales of electricity to the electric utility Xcel Energy, this hydroelectric system earned revenue of $1. 7 million for the city in 2004 Figure 5.3 Hoover Dam and lake mead on the Colorado river at the arizona-Nevada border. This installation produces 2080 MW of electrical power as well as storing water for other purposes, including flood protection, irrigation, and recreation (source: Courtesy Bureau of Reclamation/ U.S. Department of Energy) 复旦大学环境科学与工程系 Department of Environmental Science and Engineering, Fudan University
Figure 5.3 Hoover Dam and Lake Mead on the Colorado River at the Arizona-Nevada border. This installation produces 2080 MW of electrical power as well as storing water for other purposes, including flood protection, irrigation, and recreation. (source: Courtesy Bureau of Reclamation/ U.S. Department of Energy) In the late 1980s, Boulder. 6MW, 8% of electricity power used in the city The payback time for this system is 10 years, the city is making a profit on its investment. Through sales of electricity to the electric utility Xcel Energy, this hydroelectric system earned revenue of $1.7 million for the city in 2004