CHAPTER 7 HYDRO POWER
1 Hydro Power . Hydropower or water power (from the Greek: ύδρω,"water")is power derived from the energy of falling water. . Hydro power is the most widely used renewable resource in the world. . Hydropower is produced in 150 countries, with the Asia‐Pacific region generating 32 percent of global hydropower in 2010. . China is the largest hydroelectricity producer, with 721 terawatt‐hoursofproductionin2010,representingaround17 percent of domestic electricity use. . There are now four hydroelectricity stations larger than 10 GW: the Three Gorges Dam and Xiluodu Dam in China, Itaipu Dam across the Brazil/Paraguay border, and Guri Dam in Venezuela.
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 2 The Three Gorges Dam is a hydroelectric dam that spans the Yangtze River by the town of Sandouping, located in Yiling District, Yichang, Hubei province, China. The Three Gorges Dam is the world's largest power station in terms of installed capacity (22,500 MW).
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 3 Current World’s largest: Three Gorges Dam (14,000 MW)
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 4 Largest Hydro US: Grand Coulee, WA Largest hydro in US is on Columbia River Opened in 1942, expanded through 1974, capacity is 6.8 GW 380 feet hydraulic head; 125 sq miles reservoir 33 turbines, 112 MW to 800 MW size Can do pumped storage (6 x 50 MW units)
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 5 Grand Coulee Francis Turbine
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 6 What Could be Coming: Grand Inga, DR Congo Present Inga dams: 351 MW, 1,424 MW. Under development, Inga III 4,500 MW and Grand Inga 39,000 MW World Bank pledged support on 9/11/09 (est. $80 billion)
Total electric consumption in Africa for 2006 is 547 TWh (Canada = 594 TWh)
Take out RSA (228TWh) and Egypt (109TWh) 257 TWh for ca. 800 million people (321 kWh per capita)
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 7 Trends in the top five hydroelectricity-producing countries
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 8 Disadvantages of Hydropower . Large reservoirs result in submersion of extensive areas upstream . Three Gorges project displaced 106 people . Effects of natural flooding removed from system . Aquatic ecology: fish (esp. salmon) . Health hazards? Water chemistry changes (Mercury, nitrates, oxygen), bacterial and viral infections (malaria, schitosomiasis) . Limited Service Life (E.g., Three Gorges Dam has about 70 years lifetime for flood control at current rate of siltation)
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 9 Hydroelectric systems . Impoundment involving dams . eg. Hoover Dam, Grand Coulee, Three Gorges
. Diversion or run‐of‐river systems, . Run‐of‐the‐river hydroelectricity (ROR) is a type of hydroelectric generation whereby little or no water storage is provided . e.g. Niagara Falls
. Pumped storage? . two way flow: water pumped up to a storage reservoir and returned for power generation
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 10 Hydroelectric facility schematic
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 11 Racoon mountain = 1,532 megawatts (4 x 400MW) Z=100m
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 12 Hydro Setup
At top (station A): gross head (HG)=ZA
At bottom: net head (HN)
Losses: HN=HG‐HL
Potential Energy A
ZA Pressure v2 B Kinetic Energy 2g
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 13 Energy in Hydro Energy = Potential Energy + Kinetic Energy + Pressure Energy = 1 VgZ mv2 PV 2 Dimensional Analysis: kg m33 m ms 2 m kg() ms 12 N m 23 m kg m22 s kg m 22 s kg m s 2 m 2 m 3 kg m 22 s J
The power available from falling water can be calculated from the flow rate and density of water, the height of fall, and the local acceleration due to gravity. In SI
units, the power is: Where
P is power in watts η is the dimensionless efficiency of the turbine ρ is the density of water in kilograms per cubic metre Q is the flow in cubic metres per second g is the acceleration due to gravity h is the height difference between inlet and outlet in metres
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 14 Water turbine A water turbine is a rotary engine that converts kinetic and potential energy of water into mechanical work. Water turbines were developed in the 19th century and were widely used for industrial power prior to electrical grids. Now they are mostly used for electric power generation. Water turbines are
mostly found in dams to generate A Francis turbine runner, rated at nearly 750 electric power from water kinetic MW, being installed at the Grand Coulee Dam, energy. United States.
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 15 Kaplan turbine and electrical generator cut‐away view.
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 16 Water Turbine: Theory of operation Principal concepts in turbine operation: Kinetic energy of a moving fluid is converted to rotational motion of a shaft Momentum of fluid lost equals momentum applied to turbine blade if arranged in cylindrical symmetry, rate of change of angular momentum is torque transferred Turbine blades deflect fluid Impulse: energy transferred from “impact” of water on surface Reaction: energy transferred by “lift” effect
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 17 Water Turbine: Theory of operation Water turbines are divided into two groups; reaction turbines: Francis turbine Kaplan turbine Tyson turbine and impulse turbines: Water wheel Pelton wheel Screw turbine
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 18 Francis Turbine Developed in 1848 High efficiency conversion of high flow rate water
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 19 Kaplan For low head, very high flow (e.g., run of river) The head ranges from 10–70 meters and the output from 5 to 200 MW.
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 20 Pelton Wheel The original impulse turbine by Lester Pelton Water squirts out of nozzles onto sets of “buckets” attached to the rotating wheel Best for high pressure, low flow
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 21 Efficiency: Large modern water turbines operate at mechanical efficiencies greater than 90%.
Dr. Anwar Abu-Zarifa . Islamic University Gaza . Department of Industrial Engineering 22