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Hoover Dam's initial 1,345 MW power station was the world's largest hydroelectric power station in 1936; it was eclipsed by the 6,809 MW Grand Coulee Dam in 1942. [20] The Itaipu Dam opened in 1984 in South America as the largest, producing 14 GW , but was surpassed in 2008 by the Three Gorges Dam in China at 22.5 GW .
As of 2005, hydroelectric power, mostly from dams, supplies some 19% of the world's electricity, and over 63% of renewable energy. [74] Much of this is generated by large dams, although China uses small-scale hydro generation on a wide scale and is responsible for about 50% of world use of this type of power. [74]
A conventional dammed-hydro facility (hydroelectric dam) is the most common type of hydroelectric power generation. Chief Joseph Dam near Bridgeport, Washington , is a major run-of-the-river station without a sizeable reservoir.
An additional defining feature of small hydro is known as run-of-river, or that the physical impact of the project is relatively minuscule compared to major hydroelectric dams which require a water storage lake. Little water is stored behind the project, if at all, and the river is usually able to continue flowing.
Penstocks for hydroelectric installations are normally equipped with a gate system and a surge tank. They can be a combination of many components such as anchor block, drain valve, air bleed valve, and support piers depending on the application. [1] Flow is regulated to suit turbine operation and is cut off when turbines are not in service.
The ogee crest over-tops a dam, a side channel wraps around the topography of a dam, and a labyrinth uses a zig-zag design to increase the sill length for a thinner design and increased discharge. A drop inlet resembles an intake for a hydroelectric power plant and transfers water from behind the dam directly through tunnels to the river ...
Inside the Robert-Bourassa generating station, in northern Quebec, the world's largest underground power station, with an installed capacity of 5,616 MW.. An underground power station is a type of hydroelectric power station constructed by excavating the major components (e.g. machine hall, penstocks, and tailrace) from rock, rather than the more common surface-based construction methods.
A barrage dam can be used to divert water for irrigation needs or limit the amount of water downstream. In most cases, a barrage dam is built near the mouth of the river. The site of dam construction needs to be thoroughly investigated to ensure that the foundation is strong enough to support the dam and has low possibility of failing. [2]