Engineering Greatness: Three Gorges Dam ; 长江三峡水利枢纽工程

Yangtze River

Scale of river

• Yangtze River (Chang Jiang)– Origins: Kunlung Mts. of Tibet (altitude: 16,000 ft)• Also source of Mekong and Salween

– World’s 3rd longest: 3,343 miles– Rapid waters; lots of sediment– Divides China North and South– 700 tributaries– About 50,000 dams along Yangzi and tributaries

The Need• Flooding– 215 catastrophic floods in 2000 years• 1931: 186 counties; 145,000 dead; • 1935: 142,000• 1998: 4,000 dead; 14 million homeless; $24 billion

economic losses– Dam to prevent 100-year floods

• Energy– Equivalent of 15 nuclear power plants

Wuhan Flood Memorial, 1954

Mao Zedong

SwimmingGreat plans are afoot:A bridge will fly to span the north and south,Turning a deep chasm into a thoroughfare;To hold back Wushan's clouds and rainTill a smooth lake rises in the narrow gorges.The mountain goddess if she is still thereWill marvel at a world so changed

The Benefits• Flood control• Energy

– 84.7BkWh/yr = • burning 50 million tons of coal or • 25 million tons of crude oil

– effect = annually cutting• 100 million tons of carbon dioxide• up to 2 million tons sulfur dioxide• 10,000 tons of carbon monoxide• 370,000 tons of nitrogen oxide and• 150,000 tons of particulates

• National Grid– Transmission lines to rest of country

Three Gorges Dam

• Biggest hydroelectric plant in world– Fierce current now a 400-mile long placid lake– Flood control– Increase shipping– Generate clean power– Divert water to parched north

• 2009 Reservoir reached maximum height– Milestone

• $30B

History• Sun Yatsen, 1919– International Development of China

• 1932, GMD preliminary work• 1939 Otani Plan by Japan• 1944 involvement by US Bureau of Reclamation• 1980s plans revived• 1992 approved by National People’s Congress• Dec. 14, 1994 construction started– 20k-30k workers in shifts on 24-hour schedule since– 1.3 million relocated

• 2009 initially expected completion date• Fully operational by 2011

Yangzi River and 3 Gorges Reservoir

The 3 Gorges

Great Wall across the Yangzi

• Dam itself (completed in 2006)– 594 feet high– Stretches 1.5 miles– Reservoir extends 410 miles upstream (1/2 length of

California) to Chongqing• river dam, spillway structures, powerhouse, and

buildings for navigation• Reservoir– 5 trillion gallons

Scale• 32 main electric generators– 26 shore (completed 2008)– 6 underground (2011)– 700MW capacity each

• 22,500 MW – 8+ times the electricity of Hoover Dam– Sent to Central and East China, Chongqing, Guangdong– Predicted to produce 1/9 of China’s electrical power

• 10,000 ton ocean going vessels to interior• 7.0 Richter scale (2008 Sichuan earthquake: 8.0)

Three Gorges: Symbol of Pride

Major Parameters of the TGHP units and abroad power plants

Parameters Three Gorges ProjectCHINA

Grand CouleeU.S.A.

Itaipu Brazil/Paraguay

GuriVenezuela

KrasnoyarskRussia

Turbine Maximum Head(m) 113.0 108.2 126.7 146 100.5

Rated Head(m) 80.6 86.9 112.9 130 93Minimum Head(m) 71.0(61.0) 67.0 82.9 111 76

Rated Output (MW) 710 612/716 715 610 508

Maximum Output(MW) 852 827 740/808 730 508(505)

Rated Spinning Speed(r/min) 75 85.7 90.9/92.3 112.5 93.8

Runner Diameter(m) 9.525(9.800) 9.86/9.22 8.45 7.163 7.5

Generator Rated Capacity(MW) 778 718 823.6/737.0 700 500

Maximum Capacity(MW) 840 710/825.6 823.6/766 805

Frequency(Hz) 50 60 50/60 60 50Cooling Water Cooling of

StatarWater Cooling of Statar

Water Cooling of Statar

Air Cooling Water Cooling of Statar

Rated Voltage(KV) 20 15 18±5% 18 15.75

Insulation Levels F B F B

Thrust Load(t) 4,050(4,100) 4,700 4,056&4,400 2,667

Inner Diameter of Stator(m) 18,500(18,800) 18,790 16,000 13,650 16,100

Source: http://www.ctgpc.com/benefifs/benefifs_a_2.php

Three Gorges

Annual Production of Electricity: October 2010, Targets Reached

Year Number of installed units TWh

2003 6 8.607

2004 11 39.155

2005 14 49.090

2006 14 49.250

2007 21 61.600

2008 26 80.812

2009 26 79.47

2010 26 84.37

2011 26

TOTAL 26 (32) 452.354

Dissecting a Megaproject

• Why?• Who?• Benefits?• Costs?