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). The dam is
the largest operating hydroelectric facility in terms of annual energy
generation, generating 83.7 TWh in 2013 and 98.8 TWh in 2014, while the annual
energy generation of the Itaipú Dam in Brazil and Paraguay was 98.6 TWh in 2013
and 87.8 in 2014.
Except for a ship lift, the dam project was
completed and fully functional as of July 4, 2012, when the last of the main
water turbines in the underground plant began production. Each main water
turbine has a capacity of 700 MW. The dam body was completed in 2006. Coupling
the dam's 32 main turbines with two smaller generators (50 MW each) to power
the plant itself, the total electric generating capacity of the dam is 22,500
MW.
As well as producing electricity, the dam is
intended to increase the Yangtze River's shipping capacity and reduce the
potential for floods downstream by providing flood storage space. The Chinese
government regards the project as a historic engineering, social and economic
success, with the design of state-of-the-art large turbines, and a move toward
limiting greenhouse gas emissions. However, the dam flooded archaeological and
cultural sites and displaced some 1.3 million people, and is causing
significant ecological changes, including an increased risk of landslides. The
dam has been a controversial topic both domestically and abroad.
Dam:
The dam is the
most important component of hydroelectric power plant. The dam is built on a
large river that has abundant quantity of water throughout the year. It should
be built at a location where the height of the river is sufficient to get the
maximum possible potential energy from water.
Water Reservoir: The water reservoir is the
place behind the dam where water is stored. The water in the reservoir is
located higher than the rest of the dam structure. The height of water in the
reservoir decides how much potential energy the water possesses. The higher the
height of water, the more its potential energy. The high position of water in
the reservoir also enables it to move downwards effortlessly.
The height of water in the reservoir is higher
than the natural height of water flowing in the river, so it is considered to
have an altered equilibrium. This also helps to increase the overall potential
energy of water, which helps ultimately produce more electricity in the power
generation unit.
Intake
or Control Gates: These are the gates built on the inside of the dam. The water from
reservoir is released and controlled through these gates. These are called
inlet gates because water enters the power generation unit through these gates.
When the control gates are opened the water flows due to gravity through the
penstock and towards the turbines. The water flowing through the gates
possesses potential as well as kinetic energy.
The Penstock :The penstock is the long pipe or the
shaft that carries the water flowing from the reservoir towards the power
generation unit, comprised of the turbines and generator. The water in the
penstock possesses kinetic energy due to its motion and potential energy due to
its height.
