Hydropower has been used since ancient times to grind flour, pump
water and irrigate fields and perform other tasks. With the discovery of
electricity and electrical generators, by the late 19th century,
hydraulics began to be utilized to produce electrical power which in
turn started accomplishing even greater range of tasks. The world’s
first hydroelectric power scheme was developed in 1878 at Cragside in
Northumberland, England by William George Armstrong. It was used to
power a single arc lamp in his art gallery. Soon after, the first power
station came up in the Niagara Falls producing electricity in 1881.
Today,
hydropower is the most widely used form of renewable energy, but still
accounts for only 16 percent of global electricity generation. Lack of
accessible water sources is one of the main reasons why hydropower is
lagging behind alternatives such as fossil fuels and nuclear power. But
this is expected to change in the next few decades as several major
hydroelectric projects are underway mostly in the Asia-Pacific region,
that already generates 32 percent of global hydropower. China is the
largest hydroelectricity producer, with 721 terawatt-hours of production
in 2010, representing around 17 percent of domestic electricity use.
Paraguay produces 100% of its electricity from hydroelectric dams, and
Norway 98–99%. Brazil, Canada, New Zealand, Austria, Switzerland, and
Venezuela – all have a majority of the internal electric energy
production from hydroelectric power.
Let us take a look at some of the most biggest hydroelectric power plants in operation.
Three Gorges Dam, China
The
Three Gorges Dam that spans the Yangtze River in Hubei province, China,
is the world's largest power station in terms of installed capacity
(22,500 MW). Made of concrete and steel, the dam is 2,335 meters long
and 181 meters tall. More than 102.6 million cubic meters of earth was
moved to make way for 27.2 million cubic meters of concrete and 463,000
tonnes of steel, enough to build 63 Eiffel Towers. It cost the state US$
22.5 billion to build the dam.
When the water level is at its
maximum of 175 meters above sea level, which is 110 meters higher than
the river level downstream, the dam reservoir is on average about 660
kilometers in length and 1.12 kilometers in width, giving it an
effective capacity of 39.3 km3 and 1,045 square kilometers of surface
area.
The Chinese government takes huge pride in the project,
in its state-of-the-art large turbines, and its move toward limiting
greenhouse gas emissions, even though it displaced some 1.3 million
people, causing significant ecological changes as well as controversy
both domestically and abroad.
Itaipu Dam, Brazil and Paraguay
The
Itaipu Dam is located on the Paraná River on the border between Brazil
and Paraguay. Although the dam has a capacity of 14,000 MW, lower than
that of the Three Gorges Dam, it has a higher annual yield generating an
average of 91 ~ 95 TWh in comparison to 80 TWh by the latter. The plant
supplies 90% of the electricity consumed by Paraguay and 19% of that
consumed by Brazil.
The Itaipu Dam is actually four dams joined
together — from the far left, an earth fill dam, a rock fill dam, a
concrete buttress main dam, and a concrete wing dam to the right, giving
it a total length of 7235 meters. To build this massive structure, the
course of the seventh biggest river in the world had to be altered, and
50 million tons of earth and rock had to moved. To give you an idea, the
amount of concrete used to build the Itaipu Power Plant would be enough
to build 210 football stadiums; the iron and steel used would allow for
the construction of 380 Eiffel Towers and the volume of excavation of
earth and rock in Itaipu is 8.5 times greater than that of the Channel
Tunnel.
Guri Dam, Venezuela
The
Guri Dam is 7,426 meters long and 162 meters high and is located in
Venezuela on the Caroni River. As of 2009, the hydroelectric plant is
the third-largest in the world, with 10,235 MW capacity and
eighth-largest by volume of water. The Guri Dam alone supplies 73% of
Venezuela's electricity.
The dam has been the source of
controversy for a long time because the lake it created flooded some
4,250 square km of a forest that was renowned for its biodiversity and
rare wildlife, including the only place where the recently discovered
Carrizal Seedeater (a finch-like tanager) was ever found.
Tucuruí Dam, Brazil
The
Tucuruí Dam is a concrete gravity dam on the Tocantins River located on
the Tucuruí County in Brazil. The main portion Tucuruí Dam is 78 meters
high and 6.9 km long and made of concrete. The addition of the Mojú and
Caraipé earth-fill dikes increases the total length to 12,515 m. The
reservoir impounded by the dam has a capacity of 45 km³ with a live
volume of 32 km³. The main dam's Creager-type service spillway is the
second largest in the world with a maximum capacity of 110,000 m³/sec.
The dam is also used for navigation between the upper and lower
Tocantins River.
The Tucuruí Dam brings power to 13 million
people and 60% of the power is transferred to industries which create
just under 2,000 jobs. But construction of the dam attracted large
number of migrants to the area leading to deforestation and negative
impacts from increased cattle-raising. The dam also displaced between
25,000 and 35,000 people in the early 1980s, out of which 3,750 people
returned to live in the new islands created by the reservoir.
Grand Coulee Dam, the U.S.
Grand
Coulee Dam is a gravity dam on the Columbia River in the U.S. state of
Washington built to produce hydroelectric power and provide irrigation.
It was constructed between 1933 and 1942, originally with two power
plants. A third power station was completed in 1974 to increase its
energy production. It is the largest electric power-producing facility
in the United States and one of the largest concrete structures in the
world. Through a series of upgrades and the installation of
pump-generators, the dam now supplies four power stations with an
installed capacity of 6,809 MW. The reservoir supplies water for the
irrigation of 671,000 acres.
Sayano–Shushenskaya Dam, Russia
The
Sayano–Shushenskaya Dam is located on the Yenisei River, near
Sayanogorsk in Khakassia, Russia. It is the largest power plant in
Russia and the sixth-largest hydroelectric plant in the world, by
average power generation. The dam is constructed to "safely" withstand
earthquakes up to 8 on the Richter scale, and was recorded by the
Guinness Book of World Records for the strongest construction of its
type.
Longtan Dam, China
Longtan
Dam is located on the Hongshui River in Tian'e County in China. The dam
is 216.2 meters high and 849 meters long, and is the tallest
“roller-compacted concrete (RCC) gravity dam” in the world.
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